300 hp out of my stock tpi
12-11-2012, 05:04 AM
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Car: 91 gta ws6
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300 hp out of my stock tpi
Third gen i need your advise.I just brought a 1991 ws6 gta.The motor has 137,000 miles on it. everything is completely stock except for the 22 pound performance injectors that the seller has replace the original injectors with.now my goal is to get 300hp without having to do a cam change.I am open to suggestions.so you guys think that its possible without a cam change or cyclinder head work.
12-11-2012, 06:34 AM
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Re: 300 hp out of my stock tpi
Sure.
A 100 HP nitrous kit would just about do the trick.
A 100 HP nitrous kit would just about do the trick.
12-11-2012, 08:38 AM
#3
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Re: 300 hp out of my stock tpi
If you're talking about HP at the wheels, I think that would be pretty tough. 300 HP at the flywheel is possible.
When my 91 Vette (L98) still had the stock engine, I managed to get to 272 HP/370 ft lbs. (at the wheels) with just bolt-ons. The car still had the stock untouched 113s and the stock cam.
When my 91 Vette (L98) still had the stock engine, I managed to get to 272 HP/370 ft lbs. (at the wheels) with just bolt-ons. The car still had the stock untouched 113s and the stock cam.
12-11-2012, 10:45 AM
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Re: 300 hp out of my stock tpi
what are you guys considering bolt on's a different intake or keep the tpi sysytem i would be curious thanks
12-11-2012, 11:25 AM
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Car: 91 gta ws6
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Re: 300 hp out of my stock tpi
If you're talking about HP at the wheels, I think that would be pretty tough. 300 HP at the flywheel is possible.
When my 91 Vette (L98) still had the stock engine, I managed to get to 272 HP/370 ft lbs. (at the wheels) with just bolt-ons. The car still had the stock untouched 113s and the stock cam.
When my 91 Vette (L98) still had the stock engine, I managed to get to 272 HP/370 ft lbs. (at the wheels) with just bolt-ons. The car still had the stock untouched 113s and the stock cam.
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12-11-2012, 10:36 PM
#9
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Re: 300 hp out of my stock tpi
I had an acell intake, ASM runners, a ported plenum, 1.6 RRs, 24 lb FMS injectors, an AFPR, low temp fan switch, PCMforless tune, and full exhaust (headers, duals w/ X-pipe, no cat). I'm sure there was more, but I did it piece by piece over the years. The heads had never been off the car and the cam was stock. I took it from running 14.00 at 100 (stock) to a best of 12.49 at 108 before I pulled the engine for a new 383.
12-12-2012, 12:10 AM
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Re: 300 hp out of my stock tpi
You need to upgrade to at least 24 lb injectors just to feed 300 flywheel hp at 80% duty cycle. Alternatively, you can increase fuel pressure to 55 psi and effectively change your injector rating to 24.7 lb/hr. This calculator comes in handy for figuring what size you need to feed your desired power output: http://witchhunter.com/injectorcalc1.php4
Even if staying with the same heads and cam, you can upgrade to higher lift rockers if the heads allow, and roller rockers will reduce friction allowing a little gain in performance (and much more longevity of the engine due to reduced friction and thermal load). Headers and a free flowing exhaust will also help, 3rd gens have notoriously restrictive exhaust. Port/polish/port match your TPI system to remove as much restriction as possible. An aftermarket setup will change your powerband, which can be either a positive or negative based on your heads and cam. Use the CompCams Camquest free dyno software to play with different setups and see what your theoretical output might look like.
I highly recommend against nitrous as a bolt on, and never for use on a street car. Nitrous is very hard on an engine, and really requires the engine to be specifically set up for it, from the bottom up. It also various widely in its output - a 100 hp shot is really a 70 - 130 hp shot, due to the erratic ay the nitrous oxide molecule reacts, even under tightly controlled laboratory conditions. It's highly illegal to have a bottle hooked up on a street car, and can lead to your car being seized and crushed. Lastly, nitrous is only good till the bottle is empty, then you have to go to a licensed shop for a refill.
You might want to look into forced induction. Unlike nitrous, forced induction is power on demand, reliably consistent, and if kept at 1/2 atmosphere requires no engine mods to bolt on. Considering each full atmosphere effectively doubles your hp, this would easily put you over 300 hp. It is expensive, but it might be the easiest solution.
Even if staying with the same heads and cam, you can upgrade to higher lift rockers if the heads allow, and roller rockers will reduce friction allowing a little gain in performance (and much more longevity of the engine due to reduced friction and thermal load). Headers and a free flowing exhaust will also help, 3rd gens have notoriously restrictive exhaust. Port/polish/port match your TPI system to remove as much restriction as possible. An aftermarket setup will change your powerband, which can be either a positive or negative based on your heads and cam. Use the CompCams Camquest free dyno software to play with different setups and see what your theoretical output might look like.
I highly recommend against nitrous as a bolt on, and never for use on a street car. Nitrous is very hard on an engine, and really requires the engine to be specifically set up for it, from the bottom up. It also various widely in its output - a 100 hp shot is really a 70 - 130 hp shot, due to the erratic ay the nitrous oxide molecule reacts, even under tightly controlled laboratory conditions. It's highly illegal to have a bottle hooked up on a street car, and can lead to your car being seized and crushed. Lastly, nitrous is only good till the bottle is empty, then you have to go to a licensed shop for a refill.
You might want to look into forced induction. Unlike nitrous, forced induction is power on demand, reliably consistent, and if kept at 1/2 atmosphere requires no engine mods to bolt on. Considering each full atmosphere effectively doubles your hp, this would easily put you over 300 hp. It is expensive, but it might be the easiest solution.
12-12-2012, 12:56 AM
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Re: 300 hp out of my stock tpi
Now this is an excellent thread... Would there be any sense using a holley stealth ram on a stock engine with maybe a set of headers??
The 383 build I was planning is probably dead (daughter may need braces!!)
I was also wondering with increased ratio rocker (1.6) would the stock heads need maching?
I don't what to hijack this thread, but would the stealth ram on a stock engine even make sense and would this help the OP reach his goal of 300 hp?
The 383 build I was planning is probably dead (daughter may need braces!!)
I was also wondering with increased ratio rocker (1.6) would the stock heads need maching?
I don't what to hijack this thread, but would the stealth ram on a stock engine even make sense and would this help the OP reach his goal of 300 hp?
12-12-2012, 01:11 AM
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Car: 1988 Camaro IROC-Z
Engine: LB9 (305 TPI)
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Re: 300 hp out of my stock tpi
The aftermarket intakes might help move the powerband up higher, but on a stock engine they're not really worth the gains factored against the investment. You really need to match the flow characteristics of the cam, heads, intake and exhaust to really maximize power potential, otherwise you're just wasting money.
The 1.6 rockers depends on the head and cam. Some stock heads are limited on their max lift, like the Vortecs, which require machining to exceed .470" lift. Others can take the extra lift without issue. I have GM Goodwrench crate motor heads that while capable of handling the .525" max lift of my LT4 hot Cam, had to have the spring buckets machined for LT1 valve springs to handle the extra pressure. Stock springs just weren't rated for it. My problem now is finding 1.6 roller tip fulcrum style rockers that will fit under stock height centerbolt valve covers, but not break the bank.
One thing about the aftermarket intakes: A lot of people overlook the basic science of the stock TPI intake and immediate assume the runner size is too small, and replace it with larger runners, aftermarket lower intakes, or completely new systems. The TPI cross section size was selected to maximize bottom end torque, specifically for the 305, as the resonance of the airflow at lower through mid rpms produces a mild pressurization effect not unlike forced induction. The problem comes in people expecting the system to do something it simply was not designed to do, which is feed larger displacements into high rpms. If this is where you want to make your power, you need a tunnel ram design with larger cross sectional area. The trade off here is your bottom end torque, as this shifts your powerband up and loses the long runner pressurization effect. The same goes for people trying to run too large an intake runner on their heads on a smaller displacement. Even though the volume of air is higher, the actual airflow is lessened due to the loss of velocity that a small runner produces. What this means is that Stealth Ram, although having much larger runners, is going to feed less airflow at low rpms because you lose the pressurization effect of the smaller cross section, resulting in a loss of bottom end torque even though you may gain high end horsepower. The net result in the quarter mile could be devastating, especially on an otherwise stock engine.
The 1.6 rockers depends on the head and cam. Some stock heads are limited on their max lift, like the Vortecs, which require machining to exceed .470" lift. Others can take the extra lift without issue. I have GM Goodwrench crate motor heads that while capable of handling the .525" max lift of my LT4 hot Cam, had to have the spring buckets machined for LT1 valve springs to handle the extra pressure. Stock springs just weren't rated for it. My problem now is finding 1.6 roller tip fulcrum style rockers that will fit under stock height centerbolt valve covers, but not break the bank.
One thing about the aftermarket intakes: A lot of people overlook the basic science of the stock TPI intake and immediate assume the runner size is too small, and replace it with larger runners, aftermarket lower intakes, or completely new systems. The TPI cross section size was selected to maximize bottom end torque, specifically for the 305, as the resonance of the airflow at lower through mid rpms produces a mild pressurization effect not unlike forced induction. The problem comes in people expecting the system to do something it simply was not designed to do, which is feed larger displacements into high rpms. If this is where you want to make your power, you need a tunnel ram design with larger cross sectional area. The trade off here is your bottom end torque, as this shifts your powerband up and loses the long runner pressurization effect. The same goes for people trying to run too large an intake runner on their heads on a smaller displacement. Even though the volume of air is higher, the actual airflow is lessened due to the loss of velocity that a small runner produces. What this means is that Stealth Ram, although having much larger runners, is going to feed less airflow at low rpms because you lose the pressurization effect of the smaller cross section, resulting in a loss of bottom end torque even though you may gain high end horsepower. The net result in the quarter mile could be devastating, especially on an otherwise stock engine.
12-12-2012, 09:02 AM
#13
Re: 300 hp out of my stock tpi
My car saw huge gains with holley stealth ram over stock tpi but i am willing to bet full ported aftermarket tpi and big tube runners would have made just as much gains, as my race friend at the track showed with his 88 bird, with fulll bolt on tpi. Ran just as hard as i did with hsr.
However hsr swap can be done for 650 bucks. Aftermarket tpi was typically 400 base and 300-400 for runners so hsr was cheaper to do. And much easier to work on.
However hsr swap can be done for 650 bucks. Aftermarket tpi was typically 400 base and 300-400 for runners so hsr was cheaper to do. And much easier to work on.
12-12-2012, 11:07 AM
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Re: 300 hp out of my stock tpi
One thing about the aftermarket intakes: A lot of people overlook the basic science of the stock TPI intake and immediate assume the runner size is too small, and replace it with larger runners, aftermarket lower intakes, or completely new systems. The TPI cross section size was selected to maximize bottom end torque, specifically for the 305, as the resonance of the airflow at lower through mid rpms produces a mild pressurization effect not unlike forced induction. The problem comes in people expecting the system to do something it simply was not designed to do, which is feed larger displacements into high rpms.
The main thing to increase HP and torque is cylinder filling along with adding compression. Do those things and you will achieve your goals.
The trade off here is your bottom end torque, as this shifts your powerband up and loses the long runner pressurization effect. The same goes for people trying to run too large an intake runner on their heads on a smaller displacement. Even though the volume of air is higher, the actual airflow is lessened due to the loss of velocity that a small runner produces.
Over 350 @ 2500 RPMs and 430 @4600, 250 HP @2500 and 400 @ 5500 RPMs. (to the rear wheels)
Like was said, it's all in combination. (see modded runners)
12-12-2012, 11:26 AM
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Re: 300 hp out of my stock tpi
Tagging along!
I'm thinking, ported base, big runners, closer to 10:1 and something like a hot cam for mine.
I'm thinking, ported base, big runners, closer to 10:1 and something like a hot cam for mine.
12-12-2012, 04:36 PM
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Re: 300 hp out of my stock tpi
Some of us didn't believe that and set out to prove otherwise.
The main thing to increase HP and torque is cylinder filling along with adding compression. Do those things and you will achieve your goals.
My own combination disproves that theory, with a modded base flowing over 300 CFM and shortened SLP runners, my car puts down 400 HP & 430 TQ, (355 cu in)
Over 350 @ 2500 RPMs and 430 @4600, 250 HP @2500 and 400 @ 5500 RPMs. (to the rear wheels)
Like was said, it's all in combination. (see modded runners)
The main thing to increase HP and torque is cylinder filling along with adding compression. Do those things and you will achieve your goals.
My own combination disproves that theory, with a modded base flowing over 300 CFM and shortened SLP runners, my car puts down 400 HP & 430 TQ, (355 cu in)
Over 350 @ 2500 RPMs and 430 @4600, 250 HP @2500 and 400 @ 5500 RPMs. (to the rear wheels)
Like was said, it's all in combination. (see modded runners)
12-12-2012, 04:54 PM
#18
Re: 300 hp out of my stock tpi
Can't change compression without changing heads or bottom end, which precludes the OP's original stipulations, and pretty much proves my point as well. Within the stock LB9 or L89 configuration, simply changing the intake is not going to perform miracles. Everything much be matched properly or you're just wasting money.
Good 20-30 hp with intake mods and supporting bolt ons on stock cam
12-12-2012, 05:06 PM
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Re: 300 hp out of my stock tpi
While I understand the desire, IMO the longblock will likely need a rebuild in the near future for most stock tpis left out there these days anyway.
Good time for cam, increased compression, and head work.
You don't have to go wild, and many people simply want the tpi look. You just have to accept there is a limit to this design.
There are clearly a few guys here who are testing those limits. Follow their advice!
There are also clearly a lot of tpi haters, don't worth about them.
Good time for cam, increased compression, and head work.
You don't have to go wild, and many people simply want the tpi look. You just have to accept there is a limit to this design.
There are clearly a few guys here who are testing those limits. Follow their advice!
There are also clearly a lot of tpi haters, don't worth about them.
12-12-2012, 07:17 PM
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Re: 300 hp out of my stock tpi
Don't mistake my stance for hatred. I'm running a modified TPI off an 85 Corvette on a roller .040 327, with milled GM Crate motor heads modified for LT1 valve springs and .525" lift, 10.5:1 compression, LT4 Hot Cam, 30 lb/hr injectors, and Megasquirt EFI. I've built my engine around the capabilities of the TPI system, not tried to fight against it.
My above posts outline that the OP can only do so much within the confines of a stock bottom end to increase power. 20-30 hp is not an adequate trade off for a lot of the expense. It's also why I advocated forced induction as a viable route, as it gives the biggest "bang for the buck" increase in power, even with limiting the boost to 1/2 atmosphere in a bolt on configuration.
My above posts outline that the OP can only do so much within the confines of a stock bottom end to increase power. 20-30 hp is not an adequate trade off for a lot of the expense. It's also why I advocated forced induction as a viable route, as it gives the biggest "bang for the buck" increase in power, even with limiting the boost to 1/2 atmosphere in a bolt on configuration.
12-12-2012, 07:26 PM
#21
Re: 300 hp out of my stock tpi
To each his own I guess. I know people including myself that have spent ALOT more for ALOT LESS hp gains 
Forced induction done right isnt exactly cheap but really depends on your fab skills and what boost method you choose. Supercharger kits are WAY overpriced for the gains. Turbo is only way to go but thats all custom fabrication.
Forced induction done right isnt exactly cheap but really depends on your fab skills and what boost method you choose. Supercharger kits are WAY overpriced for the gains. Turbo is only way to go but thats all custom fabrication.
12-12-2012, 07:39 PM
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Re: 300 hp out of my stock tpi
To each his own I guess. I know people including myself that have spent ALOT more for ALOT LESS hp gains
Forced induction done right isnt exactly cheap but really depends on your fab skills and what boost method you choose. Supercharger kits are WAY overpriced for the gains. Turbo is only way to go but thats all custom fabrication.
Forced induction done right isnt exactly cheap but really depends on your fab skills and what boost method you choose. Supercharger kits are WAY overpriced for the gains. Turbo is only way to go but thats all custom fabrication.
http://www.ebay.com/itm/T04E-15PC-T3...3c1d67&vxp=mtr
http://www.ebay.com/itm/NEW-Small-Bl...67bbb3&vxp=mtr
http://www.ebay.com/itm/T04E-T3T4-24...973096&vxp=mtr
http://www.ebay.com/itm/SBC-SMALL-BL...1bd1e0&vxp=mtr
Considering that any aftermarket intake is going to also incur the costs of new fuel rails, larger injectors, and a custom tune, I don't figure these into the cost comparisons. But at the end of the day any of the above kits is going to give WAY more performance than any other bolt on, and allow for future increases.
12-12-2012, 08:42 PM
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Re: 300 hp out of my stock tpi
Talk about getting off base........................
The OP asked about the possibility of getting to 300HP with the stock cam and we've now escalated into talking about twin turbo kits
The OP asked about the possibility of getting to 300HP with the stock cam and we've now escalated into talking about twin turbo kits
12-13-2012, 09:10 AM
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Re: 300 hp out of my stock tpi
Don't mistake my stance for hatred. I'm running a modified TPI off an 85 Corvette on a roller .040 327, with milled GM Crate motor heads modified for LT1 valve springs and .525" lift, 10.5:1 compression, LT4 Hot Cam, 30 lb/hr injectors, and Megasquirt EFI. I've built my engine around the capabilities of the TPI system, not tried to fight against it.
My above posts outline that the OP can only do so much within the confines of a stock bottom end to increase power. 20-30 hp is not an adequate trade off for a lot of the expense. It's also why I advocated forced induction as a viable route, as it gives the biggest "bang for the buck" increase in power, even with limiting the boost to 1/2 atmosphere in a bolt on configuration.
My above posts outline that the OP can only do so much within the confines of a stock bottom end to increase power. 20-30 hp is not an adequate trade off for a lot of the expense. It's also why I advocated forced induction as a viable route, as it gives the biggest "bang for the buck" increase in power, even with limiting the boost to 1/2 atmosphere in a bolt on configuration.
I think the op's goal of 300 hp is attainable with the TPI system and he would be pleased.
12-13-2012, 04:11 PM
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Re: 300 hp out of my stock tpi
The OP asked how to reach 300 hp (did not specify flywheel or rear wheel) with a TPI with the restriction of using the stock cam and heads. This means he is very limited in what he can do to boost power output, and why I suggested forced induction. For the level of performance gain it is the most economical that can be done in a purely bolt-on fashion, if boost is kept at or below 7 psi.
12-13-2012, 05:21 PM
#27
Re: 300 hp out of my stock tpi
I dont know of any cheap bolt on turbo kits tho. ebay stuff may work but still alot of fab work to do it, depending on where you place things. If you want to keep AC or not or any of the smog stuff...really changes with the application but I agree its a very nice upgrade for the money when done but alot of work required.
12-13-2012, 09:49 PM
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Re: 300 hp out of my stock tpi
how much horsepower do yall think can be had if i were to get rid of the smog pump.I am really thinking about getting rid of it
Last edited by kad5118; 12-13-2012 at 09:57 PM.
12-14-2012, 12:55 AM
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Re: 300 hp out of my stock tpi
None, legally. In reality, about 5 hp. I'm in a non-emissions controlled county, and my car doesn't have any emissions on it. However, I am technically in violation of Federal law, even with my car's age.
As for the turbo, agreed, nothing with performance is ever truly hassle free. And the cheap bolt-ons rarely offer much actual added performance. I'm still running N/A right now because I can't afford to go forced induction, so I appreciate full well the investment I'm suggesting. I still however feel that within the confines of the OP's challenge, this is the best dollar per hp route to get to his goals. Without being able to change or re-work his existing heads, compression ratio, or cam, he's just too limited on choices. Let's consider the true costs of bolt-ons, all things considered this time;
Stealth Ram - Intake only, no fuel rails or throttle body (meaning he still has to use his stock 48mm TB) $300
30 lb /hr Accel fuel injectors, set of 8 (minimum required to feed 300 flywheel hp), $300
Fuel rails for Stealth Ram, $260
High Flow fuel pump, $100
Custom tuned chip, $100 (minimum)
Shorty Headers, $100
Y-Pipe, $150
We're already well over $1000, and I've listed the bare bones cost on the above (assuming Summit Shorty Headers, MSD 46 gal/hr fuel pump, Flowtech Y-pipe, and the minimum cost for a custom tuned EPROM based on the price list in my Year One catalog). If he goes with an aftermarket ECM the price jumps by $450 minimum for MS-II, others being far more expensive. All for how much actual gain? 30 hp? 50 hp? Let's even assume that this $1,310 investment nets him 100 hp. Factor that against $1,592 for the first Ebay turbo kit I listed, plus the fuel injectors, fuel pump, and y-pipe, with a horsepower gain of at LEAST 100 hp, probably closer to 150, at only 7 psi, plus the ability to upgrade later to a full atmosphere or more and double his hp.
Again, I'm basing all of this on not being allowed to touch the stock heads or cam and still meet his goals.
As for the turbo, agreed, nothing with performance is ever truly hassle free. And the cheap bolt-ons rarely offer much actual added performance. I'm still running N/A right now because I can't afford to go forced induction, so I appreciate full well the investment I'm suggesting. I still however feel that within the confines of the OP's challenge, this is the best dollar per hp route to get to his goals. Without being able to change or re-work his existing heads, compression ratio, or cam, he's just too limited on choices. Let's consider the true costs of bolt-ons, all things considered this time;
Stealth Ram - Intake only, no fuel rails or throttle body (meaning he still has to use his stock 48mm TB) $300
30 lb /hr Accel fuel injectors, set of 8 (minimum required to feed 300 flywheel hp), $300
Fuel rails for Stealth Ram, $260
High Flow fuel pump, $100
Custom tuned chip, $100 (minimum)
Shorty Headers, $100
Y-Pipe, $150
We're already well over $1000, and I've listed the bare bones cost on the above (assuming Summit Shorty Headers, MSD 46 gal/hr fuel pump, Flowtech Y-pipe, and the minimum cost for a custom tuned EPROM based on the price list in my Year One catalog). If he goes with an aftermarket ECM the price jumps by $450 minimum for MS-II, others being far more expensive. All for how much actual gain? 30 hp? 50 hp? Let's even assume that this $1,310 investment nets him 100 hp. Factor that against $1,592 for the first Ebay turbo kit I listed, plus the fuel injectors, fuel pump, and y-pipe, with a horsepower gain of at LEAST 100 hp, probably closer to 150, at only 7 psi, plus the ability to upgrade later to a full atmosphere or more and double his hp.
Again, I'm basing all of this on not being allowed to touch the stock heads or cam and still meet his goals.
12-14-2012, 01:54 AM
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Axle/Gears: 3.23
Re: 300 hp out of my stock tpi
None, legally. In reality, about 5 hp. I'm in a non-emissions controlled county, and my car doesn't have any emissions on it. However, I am technically in violation of Federal law, even with my car's age.
As for the turbo, agreed, nothing with performance is ever truly hassle free. And the cheap bolt-ons rarely offer much actual added performance. I'm still running N/A right now because I can't afford to go forced induction, so I appreciate full well the investment I'm suggesting. I still however feel that within the confines of the OP's challenge, this is the best dollar per hp route to get to his goals. Without being able to change or re-work his existing heads, compression ratio, or cam, he's just too limited on choices. Let's consider the true costs of bolt-ons, all things considered this time;
Stealth Ram - Intake only, no fuel rails or throttle body (meaning he still has to use his stock 48mm TB) $300
30 lb /hr Accel fuel injectors, set of 8 (minimum required to feed 300 flywheel hp), $300
Fuel rails for Stealth Ram, $260
High Flow fuel pump, $100
Custom tuned chip, $100 (minimum)
Shorty Headers, $100
Y-Pipe, $150
We're already well over $1000, and I've listed the bare bones cost on the above (assuming Summit Shorty Headers, MSD 46 gal/hr fuel pump, Flowtech Y-pipe, and the minimum cost for a custom tuned EPROM based on the price list in my Year One catalog). If he goes with an aftermarket ECM the price jumps by $450 minimum for MS-II, others being far more expensive. All for how much actual gain? 30 hp? 50 hp? Let's even assume that this $1,310 investment nets him 100 hp. Factor that against $1,592 for the first Ebay turbo kit I listed, plus the fuel injectors, fuel pump, and y-pipe, with a horsepower gain of at LEAST 100 hp, probably closer to 150, at only 7 psi, plus the ability to upgrade later to a full atmosphere or more and double his hp.
Again, I'm basing all of this on not being allowed to touch the stock heads or cam and still meet his goals.
As for the turbo, agreed, nothing with performance is ever truly hassle free. And the cheap bolt-ons rarely offer much actual added performance. I'm still running N/A right now because I can't afford to go forced induction, so I appreciate full well the investment I'm suggesting. I still however feel that within the confines of the OP's challenge, this is the best dollar per hp route to get to his goals. Without being able to change or re-work his existing heads, compression ratio, or cam, he's just too limited on choices. Let's consider the true costs of bolt-ons, all things considered this time;
Stealth Ram - Intake only, no fuel rails or throttle body (meaning he still has to use his stock 48mm TB) $300
30 lb /hr Accel fuel injectors, set of 8 (minimum required to feed 300 flywheel hp), $300
Fuel rails for Stealth Ram, $260
High Flow fuel pump, $100
Custom tuned chip, $100 (minimum)
Shorty Headers, $100
Y-Pipe, $150
We're already well over $1000, and I've listed the bare bones cost on the above (assuming Summit Shorty Headers, MSD 46 gal/hr fuel pump, Flowtech Y-pipe, and the minimum cost for a custom tuned EPROM based on the price list in my Year One catalog). If he goes with an aftermarket ECM the price jumps by $450 minimum for MS-II, others being far more expensive. All for how much actual gain? 30 hp? 50 hp? Let's even assume that this $1,310 investment nets him 100 hp. Factor that against $1,592 for the first Ebay turbo kit I listed, plus the fuel injectors, fuel pump, and y-pipe, with a horsepower gain of at LEAST 100 hp, probably closer to 150, at only 7 psi, plus the ability to upgrade later to a full atmosphere or more and double his hp.
Again, I'm basing all of this on not being allowed to touch the stock heads or cam and still meet his goals.
12-14-2012, 02:07 AM
#31
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Car: 1988 Camaro IROC-Z
Engine: LB9 (305 TPI)
Transmission: 700R4
Axle/Gears: 2.73 Positraction
Re: 300 hp out of my stock tpi
It's quite the sticker shock. Performance = money, no way around that. Even "free" mods require some form of investment, even if its just labor and time. At some point if you really want to make more power with your current setup you're going to have to pull the heads and either rework or replace them, and do a cam swap. But again, this is going to require more investment in fueling and engine management to run properly (I.E. injectors, fuel pressure, and ECM mods/tuning).
If I don't stick with my Gen I SBC, I'll eventually upgrade to an LS motor. The 5.3L swaps have dropped in overall cost, but the piecemeal nature of the swap can still run up a bit. My plan is to find a wrecked (but running) 99-02 LS1 Camaro or Firebird on Craigslist, pull the entire drivetrain from it to swap, part out everything else salvageable from the car on Craigslist and Ebay, and ultimately scrap what's left. This way the cost is kept down because there is no piecemeal purchasing of various parts (accessories, fuel tank, transmission, etc), everything will fit an F-Body without issue (save an aftermarket crossmember), and by parting out the car and scrapping the remainder I can recoup some losses. Ideally I hope the project costs between $2000-$3000 when all is said and done.
If I don't stick with my Gen I SBC, I'll eventually upgrade to an LS motor. The 5.3L swaps have dropped in overall cost, but the piecemeal nature of the swap can still run up a bit. My plan is to find a wrecked (but running) 99-02 LS1 Camaro or Firebird on Craigslist, pull the entire drivetrain from it to swap, part out everything else salvageable from the car on Craigslist and Ebay, and ultimately scrap what's left. This way the cost is kept down because there is no piecemeal purchasing of various parts (accessories, fuel tank, transmission, etc), everything will fit an F-Body without issue (save an aftermarket crossmember), and by parting out the car and scrapping the remainder I can recoup some losses. Ideally I hope the project costs between $2000-$3000 when all is said and done.
12-14-2012, 05:11 PM
#33
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Car: 1988 Camaro IROC-Z
Engine: LB9 (305 TPI)
Transmission: 700R4
Axle/Gears: 2.73 Positraction
Re: 300 hp out of my stock tpi
That's actually not a bad deal, if I currently had the case. Between the go fast parts I wouldn't be using and could resell, and the car not being wrecked, it would give more to part out to offset the cost. But a great example of exactly what I meant.
01-07-2013, 02:59 PM
#34
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Car: 1986 Camaro, 2004 9c1 impala
Engine: TPI 350, previous owner hackjob
Transmission: built out 700r4
Axle/Gears: 4th gen, 373, LSD, GIRDLE
Re: 300 hp out of my stock tpi
Does anyone have some real experience with an EBay turbo kit? 1500 and 150hp sounds really fishy. And then the question is what are you really getting? How long will it last?
01-07-2013, 06:53 PM
#35
Member
Re: 300 hp out of my stock tpi
I really wish I would have kept the dyno graph of the last budget Stealth Ram motor we built a few years ago. I'll see if my buddy still has it; LT's, SVO injectors, 1.6 RR's on a stock lt1 cam and port matched to stock heads.
The combo performed very well, and the power per dollar was well spent. The customer had requested 300 flywheel HP and this modest combo does it. Anyone that says an intake swap isn't worth while has no real world experience building, or dynoing these motors, and is talking out of their ***.
Some more head work and a better cam, and 300whp wouldn't have been hard. Stock fuel pump is fine at 300hp also. Shop some used parts and you'll come in WAY under the cost of forced induction.
The science of the LTR TPi intake setup on a 350 is...it's too small. Hence L98's show great improvements to both intake and exhaust mods. Now I'm not saying that the SR is idealy tuned for the stock cam and heads...it's not. But, it will still show improvement over the LTR setup across the power band.
Might I remind you, GM paired a miniram (also a short runner, high rpm intake) up with almost the same head and cam package as the L98. They reverse cooled it, updated the ignition to the optispark and called it an LT1
The combo performed very well, and the power per dollar was well spent. The customer had requested 300 flywheel HP and this modest combo does it. Anyone that says an intake swap isn't worth while has no real world experience building, or dynoing these motors, and is talking out of their ***.
Some more head work and a better cam, and 300whp wouldn't have been hard. Stock fuel pump is fine at 300hp also. Shop some used parts and you'll come in WAY under the cost of forced induction.
The science of the LTR TPi intake setup on a 350 is...it's too small. Hence L98's show great improvements to both intake and exhaust mods. Now I'm not saying that the SR is idealy tuned for the stock cam and heads...it's not. But, it will still show improvement over the LTR setup across the power band.
Might I remind you, GM paired a miniram (also a short runner, high rpm intake) up with almost the same head and cam package as the L98. They reverse cooled it, updated the ignition to the optispark and called it an LT1
Last edited by Anti-Venom; 01-07-2013 at 07:11 PM.
01-07-2013, 09:25 PM
#36
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Car: 91 gta ws6
Engine: L98
Transmission: 700 R4 TRANS
Axle/Gears: 3.23
Re: 300 hp out of my stock tpi
I really wish I would have kept the dyno graph of the last budget Stealth Ram motor we built a few years ago. I'll see if my buddy still has it; LT's, SVO injectors, 1.6 RR's on a stock lt1 cam and port matched to stock heads.
The combo performed very well, and the power per dollar was well spent. The customer had requested 300 flywheel HP and this modest combo does it. Anyone that says an intake swap isn't worth while has no real world experience building, or dynoing these motors, and is talking out of their ***.
Some more head work and a better cam, and 300whp wouldn't have been hard. Stock fuel pump is fine at 300hp also. Shop some used parts and you'll come in WAY under the cost of forced induction.
The science of the LTR TPi intake setup on a 350 is...it's too small. Hence L98's show great improvements to both intake and exhaust mods. Now I'm not saying that the SR is idealy tuned for the stock cam and heads...it's not. But, it will still show improvement over the LTR setup across the power band.
Might I remind you, GM paired a miniram (also a short runner, high rpm intake) up with almost the same head and cam package as the L98. They reverse cooled it, updated the ignition to the optispark and called it an LT1
The combo performed very well, and the power per dollar was well spent. The customer had requested 300 flywheel HP and this modest combo does it. Anyone that says an intake swap isn't worth while has no real world experience building, or dynoing these motors, and is talking out of their ***.
Some more head work and a better cam, and 300whp wouldn't have been hard. Stock fuel pump is fine at 300hp also. Shop some used parts and you'll come in WAY under the cost of forced induction.
The science of the LTR TPi intake setup on a 350 is...it's too small. Hence L98's show great improvements to both intake and exhaust mods. Now I'm not saying that the SR is idealy tuned for the stock cam and heads...it's not. But, it will still show improvement over the LTR setup across the power band.
Might I remind you, GM paired a miniram (also a short runner, high rpm intake) up with almost the same head and cam package as the L98. They reverse cooled it, updated the ignition to the optispark and called it an LT1
02-11-2013, 03:56 PM
#37
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Car: 1988 Pontiac Trans Am GTA
Engine: L98 TPI
Transmission: 700R4
Re: 300 hp out of my stock tpi
Rule #2 You get what you pay for. I often say, "Free has its own inherent value."
Rule #3 If it seems too good to be true, it probably is.
In the end, if you bought this, had to spend $$$$$$$$ fabricating it, probably have little to no customer support, and if it all blows up...you have no one to go after.
I am looking at the same question as the OP. 300 ponies with little extreme modification. I am not looking to do a heart transplant - that is why I have the LT1 Firebird 'vert. I don't want to carve up the TPI and the car...the motor is barely broken in!
It is just cheaper to get both!
I know forced induction is pricey as I am looking at it for my 88 GTA, but I am not going to ever put some eBay job on my girl...warranty, support, and reliability is what I am paying for...
Otherwise, live within the limits of the engine IMO. Realisticly (and reading this thread only cements my thoughts), unless you are planning on doing a hell of a lot - well - enjoy the classic for what she is and the time she represents. The biggest boob job and tummy tuck won't disguise that my better half is...er...20 years old again + a few...and I love her still.
Just my $0.02
02-11-2013, 10:39 PM
#39
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Car: 67 ******mobile
Engine: 385 Solid roller
Transmission: T-56
Axle/Gears: 4.11
Re: 300 hp out of my stock tpi
Dont put that cheap ebay garbage on your car if you value it.
Youll have plenty of fab stuff $$ on top of it.
Nothing aftermarket (almost) is truly bolt on theres always something that needs tweaking. It adds up.
Youll have plenty of fab stuff $$ on top of it.
Nothing aftermarket (almost) is truly bolt on theres always something that needs tweaking. It adds up.
02-11-2013, 11:36 PM
#40
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Car: 89 RS 89 iroc 87 firebird
Engine: 3.1 Turbo/ 355 twin turbo
Transmission: a4 w/ 4500 stall/ a4 / t5
Axle/Gears: strange s60 /w 3:42's
Re: 300 hp out of my stock tpi
depends on the kit and what turbos they come with
i have ebay turbos that are going strong after 8 years and over 100,000 miles.
i ahve used tons of them and never had a single failure except for 1 that was my fault
only ebay blow off valve worth a dam thing is the rfl knockoff
and most of the wastegates work just fine
the bar and plate intercoolers work friggen great i have them on all of my cars and have done testing to compare them to high dollar brand name units the difference was about 7 hp on a 400 hp v6
when it comes to ebay stuff take advice from ppl who have actually used the stuff, not from ppl who have never had there hands on the stuff or used it.
tons of ppl here have used ebay stuff with out ever having an issue
02-22-2013, 08:12 AM
#41
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Car: '91 Z28
Engine: L98 5.7L TPI
Transmission: 700R4
Axle/Gears: 323's
Re: 300 hp out of my stock tpi
interesting thread... cuz i was sorta' wondering what mine is gonna do when it goes to the dyno for tuning in another week or two. i've installed the LT4 hotcam and had the heads machined for the springs and 1.6 rockers, have 1-3/4 headers w/flowmaster exhaust. also added an afpr, but may be lacking in the injector department. i replaced them once before but with other gm's and can't even recall the p/n, but iirc, the flow was close to 24 when they were cleaned... do you think there'd be a need to replace those before i put it on the dyno? i don't really want to dyno it twice to make sure it's done right, even tho that might be twice the fun. next time around i'll focus on the intake and heads...
02-22-2013, 08:51 AM
#42
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Car: 91' Firebird SOLD
Engine: 350 TPI +bolt-ons
Transmission: 700r4
Axle/Gears: 3:42
Re: 300 hp out of my stock tpi
interesting thread... cuz i was sorta' wondering what mine is gonna do when it goes to the dyno for tuning in another week or two. i've installed the LT4 hotcam and had the heads machined for the springs and 1.6 rockers, have 1-3/4 headers w/flowmaster exhaust. also added an afpr, but may be lacking in the injector department. i replaced them once before but with other gm's and can't even recall the p/n, but iirc, the flow was close to 24 when they were cleaned... do you think there'd be a need to replace those before i put it on the dyno? i don't really want to dyno it twice to make sure it's done right, even tho that might be twice the fun. next time around i'll focus on the intake and heads...
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