Phoenix'97

I hope I am on the right forum for this question. To make a long story short, I am researching the notion of building my LT1 motor with the TPI intake granted I am optimizing the motor for the lower to mid-range torque as my daily driver and a car that won't be raced at the track.

I am having a hard time finding information about this possible modification to my motor since more often than not I have too many opinions trying to dissuade me from this research without really giving me a solid reason as to why I should not do it. I am now on this forum, among owners of TPI F-bodies, so that I may have your take on this, have an idea of what I would be getting myself into with a TPI intake that is often bashed for being restrictive, obsolete, and no longer relevant. For my build goals and criteria, the TPI seems to be a solid choice granted I have no other intake selection to swap onto my motor that suits my build goal and driving style.

So, with this said, I would appreciate your experience, wisdom, and technical knowledge applied to swapping a TPI intake onto an LT1. Also, can I use my stock camshaft with this intake or should I use a stock camshaft tuned for lower end and mid-range torque, like a B-Body LT1 camshaft with specs nearly identical to the L31 camshaft?

Tuned Performance

iTrader: (92)

Not sure if this is true or not but I have heard the vortec base will fit on lt1 heads. The coolant passages would not be used.

Phoenix'97

Yeah, I looked into it. The vortec base is taller than one required for the LT1 heads. I was thinking about asking Scoggin-Dickey if they might be able to fabricate a base for the LT1 based on their Vortec base. If not, I need to have a machine shop add more material to the TPI base and then fabricate it to match my LT1 intake base. It will probably need some port matching but it should be doable.

Tuned Performance

iTrader: (92)

Accel made a lt1 tpi base it’s extremely hard to find. I’ve only seen two one on eBay and a friend has one that he won’t let go of .

Phoenix'97

Yeah, I know about it but I am not that interested in it. I don't need torque performance beyond 5000 RPM for my daily driving experience and when I do launch from a green light for fun. From what I have seen of torque curves from TPI L98s compared to my LT1, the torque curve of the TPI falls within the RPM range I spend most of my time driving and falls off where I rev the motor the highest, around 5000 RPM. This is why I am more set on a TPI intake, unless someone has a strong case for why this is a bad idea.

For a pure street car, I don't see why the TPI intake would be a bad idea, especially if I equip one with AS&M big tube runners and have the entire unit extrude honed for that last bit of airflow before it starts to choke off.

BadSS

This guy was mating a FIRST intake up to LT1 heads. It looks doable without to much work. Would cost less and flows better than an extrude honed TPI also.

http://garage.grumpysperformance.com...1-build.11781/

Abubaca

iTrader: (3)

I am absolutely, 100% completely for you doing this.... ....but.... I'm still not completely sure why you would do this. Traditional 350s, LT1 350s, there all cheap and easy to work on, and available anywhere if ya wanted to pick up a regular 350, ...and stock LT1's aren't exactly slow. (compared to a TPI 350). Torque curves on a dyno are totally different than torque curves in real life. I never had trouble doing burnouts in a stock LT1 car. Plenty of torque, but certainly more revs. ...you're talking to a guy with a TPI on a 383, so you don't need to convince me of a reason to go TPI. ....but without a nostalgia card tugging my heartstrings, I'd never CHOOSE the TPI over another intake.

But I'd sure love to see you succeed, so good luck! I'm rooting for ya.

Phoenix'97

The only issue that may arise is the inability to fit the FIRST plenum under my very cramped engine bay with the wiper linkage cowl that sits directly over the intake manifold, a third of the way over the rear of the motor. My LT1 intake manifold is six inches tall and the stock TPI intake is nine inches tall at most. I have three inches of clearance before I am hitting the bottom-most part of the wiper linkage cowl.

I know the FIRST TPI intake flows better but airflow wise an extrude honed stock TPI is really all the airflow I should need up to 5000 RPM using my stock LT1 camshaft with 1.5 RRs or the B-body LT1 camshaft with more low end torque production.

Again, I am doing early research to piece together the right parts to put on this motor to give me the very mild performance I seek, something similar to driving an L98 TPI car.

Phoenix'97

Well it is really simple, I drive my LT1 car like it is a TPI L98. I don't race it, it is purely my daily driver and cruiser, but I want some more seat-of-the-pants feel when I take off launching from a green light. Yes, the LT1 should have comparable low end torque to the TPI L98, but I am still not happy with the car in it's stock form. Since I am not interested in high RPM torque production to take advantage of the GM copy of the TPIS miniram intake, it makes sense that I optimize the LT1 motor by swapping on a TPI intake. I just need to figure out whether I will be happy with my stock LT1 camshaft with 1.5RRs or whether I should swap that stock camshaft out for the B-Body LT1 camshaft which produces more low end torque to really give me what I am seeking in a very mild and stockish build without any major loss in my city mileage.

Orr89RocZ

iTrader: (20)

You are basically doing the reverse of LT1 intake swap to sbc. Guys have done that conversion, including myself.

You basically need to block off the dizzy hole and redrill the intake bolt holes to the heads. Fill in the old ones helps. You wont use the coolant ports in the intake so could block those off too if ya want

Street Lethal

iTrader: (16)

I don't agree with any of this. You're running an '97 LT1 and are looking to swap to a TPI intake manifold because you want a more obstructed intake charge for the RPM band you're more oriented with? If this is the case, drop the TPI intake manifold idea, and take advantage of the six speed by running either 4.10 through 4.56 gears out back dependent on your desired RPM and range. It's the same difference, except you won't need to go through the ridiculous hassle and process of going backward, fitting and adapting the TPI manifold, then tuning for it. Don't mean to sound harsh, but gearing is the way to go in your case, not intake manifolds...

- Rob

Abubaca

iTrader: (3)

I'm with Rob on this. ...although I'm still 100% for you doing it. Love to see it get done. I just don't think it's the solution to your problem, if you'd call it that. Put it this way, if your question is HOW....then I'm subscribing. If your question is SHOULD I, then no. You shouldn't. But my car is a 20 year compilation of things I probably shouldn't have done, so I'm with ya either way.

Orr89RocZ

iTrader: (20)

Will it even fit without cutting the windshield cowl?

Phoenix'97

It comes down to this, I hope a machine shop can add more material to the TPI base and fill in the drill holes. They would then have to match the drill angles to my supplied sample of LT1 intake. There is an aftermarket metal cover "delete" for the coolant hose so that is a simple screw-on deal. The distributor hole will not be seen as it will be tucked behind my motor and under that overhead cowl where even the TPI runners will block it's view! I am not worried about the distributor hole unless it will pose some problem I am unaware of.

You are not alone and you are not being harsh! This is why I am asking around forums! If I am wrong, I am wrong, but so far everyone is pushing their philosophy and notion of what is better on me, and this usually means building a race car, not a daily driver that is strictly a street car! I have guys on other forums arguing with me about this, suggesting I just stroke the motor and be done with it. However, I am unwilling to sacrifice city mileage for more displacement! I drive my car in the winter, I can't have it slurping gasoline with more displacement when I have been stuck idling in traffic with a commute that should have been 15-minutes lasting an hour or more! This is why I am focusing on other avenues to give me a taste of what that higher displacement motor would feel like while maintaining my fuel economy or even improving it a tad with the tow camshaft.

I have had guys immediately suggest lower gears such as 4.10, but again, I have no interest in driving my car in the high rpm band where it makes it's power! Futhermore, this higher RPM band driving will hurt my city mileage if I drive as such but it will also reduce my highway mileage because now on sixth gear I won't be driving 65 MPH at 2000 RPM, it will be more higher and this results in more fuel consumption, and I have a strict requirement to maintain my EPA fuel mileage, if not improve it if possible! So again, this is where the TPI intake paired with maybe that tow cam version of my stock LT1 camshaft, and my factory 3.42 gear ratio satisfies this criteria!


Just as long as you are willing to give me your impressions and not threatening to have me banned for asking this question! Yes, it is crazy to spend the money only to detune my LT1 in some respects. However, I drive my car like an 18-wheeler, I used to be a truck driver, it's a good habit, and I shift my car like it's a TPI L98, the highest I will go is 5000 RPM. The factory RPM limiter is set at 6500 and the car starts sounding like it's struggling after 6000 RPM, likely the limiter slowly getting ready to activate. So, I shift at maximum by 5000 RPM. The only fun I have is launches from a green light up to the speed limit, usually for this 45 MPH, and racing onto the expressway from a clear on-ramp up to 60 MPH. I want to feel more pull than I do from idle on up to where I shift the car, at 5000 RPM. So again, a tow cam version of my stock LT1 camshaft, that of the B-Body LT1, paired with a TPI intake, seems like the ideal set-up!

The stock TPI should fit, but the FIRST TPI may be a bit too beefy to fit. My LT1 intake is six inches tall and the stock TPI intake is nine inches at most. I have three inches of clearance with my stock LT1 intake which means the stock TPI intake is going to be a tight fit but it should fit under the cowl. If necessary, I can have a custom shop try to work their magic to get the TPI intake to fit comfortably and not act like some additional body support for the cowl area of the engine bay! Maintenance on the TPI intake for any future problems like the EGR valve or fuel pressure regulator may be a royal pain, but it should be doable! I am used to cutting my knuckles in the engine bay of my LT1 anyways, but I wish GM gave it the more spacious room of it's third gen predecessor!

Bow_Tied

iTrader: (1)

This is a really interesting conversation, I like the various view points.

Going from a 3.42 to a 4.10 will make 1st gear feel pretty short and depending on which T56 you have and driver preferences it could be too much for a daily driver. If you have the 2.66:1 1st it wouldn't be as bad as the 2.97:1 of course, but still short. Having had a car with 4.10s I can attest to the **** load of fun they are, but for regular daily use I could certainly see them getting old fast. Changing to a gear set in between could work, say 3.73s, but this isn't going to be as big of "seat of the pants" difference, some yes, but not as much as jumping into the 4s imo. For what I understand your needs to be, the gains in a gear swap seem marginal for the expense in the swap itself and the day to day economy.

For the cam - I get where you are going with the B-body cam. If you were planning to change cams, and I think you should consider it or at least investigate further, I humbly suggest that you not limit it to a B-body stock cam that is 20 years old in design. Check Lunati or others and see if there is a modern B-body cam that bumps up low end grunt like you want without the sacrifice of small lobe separation/overlap that makes power in high rpms. Perhaps that is what you meant, apologies if I misunderstood.

Is your budget fixed tightly? Something you could do to really improve options today/future is do a coil on plug and LSX ECM conversion with a kit from www.Torqhead.com. Lots of future opportunity to tune it to your needs, it eliminates the opti spark, and is a bolt on. The owner of Torqhead, Paul, owns a '96 Impala SS and knows these B body cars really well - he is super easy to talk to and very knowledgeable. I suggest you give him a shout and tell him what you are up to and he can talk you through some pros and cons of various things and let you decide what's right for you. He is not the type to try and sell you on something you don't need. Tell him I referred you.

I am interested to see how your build goes whichever direction you take.
Cheers.

articwhiteZ

iTrader: (56)

Oops

articwhiteZ

iTrader: (56)

forget about the supper ram for RPM..its done by 5500rpm..dont matter what cam..or how big you make the runners....

with a lingenfelter stage5 11.1 383sbc and the largest mech roller lingelfelter used with the super ram 383.. it was done by 5700prm...
I see guys still tryn to port the cr$p out the the super ram...the only way to get it to pull into the 6500rpm and make power..is NOS on it

pic of the stage5 383 with fogger nos 1992..been there done that.. got the T shirt..

now if you want RPM...Well

Orr89RocZ

iTrader: (20)

Not sure what you dont like about the lt1. I've tuned a half dozen of them from stockish bolt ons to heads cam. Always loved how they felt. Smooth broad torque curve. I've done many tpi cars as well, stockish, cam only, heads cam, blown, turbo etc. they definitely are peak torque winners but fall off pretty quick. I am not sure its gonna feel as good as you hoped cuz you will be losing 40-50 hp easily with stock base and runners. Stock lt1 is done by 5800 with stock cam. Thats already a nice tight power band.

Also had a lt1 swapped thirdgen with bolt ons and 4.10 gears in an 4l60e. It was a blast! But i can understand mileage concerns. You'll see a bigger hit in the highway than city tho


If anything i would consider 3.73 gears and a mild camshaft. Short duration somewhere around stockish plus 5-8 deg, but a aggressive fast lobe. Tighter lsa. Would really help quicken throttle response and low end power. Fast valve motion and abit more overlap will build torque much sooner on the lt1 intakes. Xfi260 cam would be cool to try but on a 109 lsa

Whatever you do do not swap stock lt1 cam for the B body

Phoenix'97

Well, as soon as I get my college loan debt paid off after I graduate, I was planning on taking out a loan to pay for the resto-modding of my car which would also include the motor build. However, some guys on other forums have me wondering if I should play it safe and slowly add the major parts on my LT1 before doing it all at once without knowing if I am happy with the results or not. So, I may go this route while paying down my student loan. I am awfully tempted to throw on a TPI intake first before a camshaft, since my stock camshaft is almost spec'd the same way as the 88-89 L98s with the 117 lobe separation. If I still crave more performance, I can then look into the B-Body LT1 camshaft, or rather, an improved version if one exists!

I have thought about the gearing issue for awhile and really, for the sake of optimal fuel economy and where the car spends most of it's time in the RPM range, I would really prefer to keep my stock 3.42 and focus on the torque production aspect to give me what I am seeking.

Oh yeah! I do intend to use a coil conversion kit, I have read about the LTCC coil conversion pack or the Deltec Opti-Direct, although they require the signal from the optispark to function. If I could actually replace the optispark with the direct ignition system off the LS motors, I would be so happy! I can't tell you how many botched repair jobs from mechanics shops I have had trying to replace failed optisparks and their install of my water pump lead to the failure of that brand new optispark! Honestly, I think the cam driven water pump is a very efficient and superior system with less parasitic drain on your motor's power than a belt driven pump, and if the belt brakes you still have the cam driving the water pump, but the LT1 water pump is notorious for leaking if seals are not perfectly installed and not enough TLC is given with lots of gasket sealer and ample time to cure!

Anyways, yeah, if I can delete the optispark I will! The coil conversion kits used by some owners result in better idle quality and marginal power increase by their account! If I am trying to improve upon my LT1, it is a great place to start! Thanks for pointing this out to me, I didn't know I could do it!

Phoenix'97

Well the problem is I am very stubborn and I am trying to have my cake and eat it too, so to speak. I have a daily driver, I don't race it, the only fun I have is gunning it from a green light up to the speed limit, usually any place that is 45 MPH or higher! Yes, it would probably be more fun with a lower gear but I need to be mindful of my fuel economy, and I already speed shift to keep my RPM at 2000 for cruising. It would bother me to hell to have to shift into higher gears to cruise at 2000 RPM. I would prefer to stay in gear longer! So, I have many reasons for why I don't want a lower gear ratio, my driving style is not compatible with it. So, how do I achieve that same feeling without the use of a lower gear ratio? More low end and mid-range torque?! This is why I am obsessed with the TPI intake, the more I read about it the more I realize that it is perfect for my driving style, my criteria, and my notion of "performance" with regards to a daily driven "muscle" car being mindful of fuel economy!

You have me worried, why exactly should I not swap in a B-Body LT1 camshaft with a lobe separation of 111 but spec'd to perform similarly to the F-Body/Corvette camshaft? Would you still recommend I not swap in this camshaft with a TPI intake on the LT1?! This is the reason I am asking around on many forums!

Street Lethal

iTrader: (16)

Just remember the original concept; it's your daily driver, and you don't race it. You just want more pull from a stop light, and in the lower RPM range. Don't get carried away with mismatching parts, because in the end you'll be chasing your tail to get it right, then you need to dyno tune it to bring it all in together, and you might not even be happy with the results. With the gear swap, the engine will have the same manners, but your RPM band and how fast you get to that sweet spot, as well as remain in that sweet spot, becomes the key. Here is an LS1 in a '99 Camaro running 4.56 gears with the six speed, which is essentially a similar scenario as your LT1 when compared to an L98. You will be much happier with the gear swap in your case, no need to open the engine whatsoever...

- Rob

Abubaca

iTrader: (3)

First of all....this forum is typically happy to help you with whatever you wanna do. You'll get lots of advice, and definitely not always the advice you want, but if you wanna do it, we're typically gonna be supportive.

As for your logic, regarding gearing, more torque, RPM band for street driving etc. etc., I think you're spot on. The issue is more what's the real world difference versus the difference on paper. There's no doubt that the short runner LT1 intake will flow more up high and lose torque down low. There's no doubt the opposite is true for the TPI. And there's no doubt that a street motor has different needs than a race motor. There's no doubt that deeper gears will have you shifting quicker. ....but the real world difference, for what you're building, I doubt it'd ever make a difference. The LT1 has MORE than enough torque to get you off the line and spin the tires if ya want. And if you DO feel ya need a little more, then move to a 3.73 gear, not a 4.10. Mostly stock cams, with mostly stock gear ratios on stock displacement motors.....you're not talking much of a difference. The dyno will see the difference. Your ETs if you were racing would see the difference, but for day to day.....bah.....just drive it.
I think you're talking about some pretty elaborate custom work for an absolutely minimal difference.

Orr89RocZ

iTrader: (20)

I am not sure i follow you here. T56 with 3.42, 4th gear is 44 mph at 2000 rpm. 5th gear is 60mph. 6th gear is 89 mph
With 3.73, 4th gear is 41 mph. 5th gear is 55 mph at 2000 rpm. 6th is 82 mph.

Your best mileage will come in overdrive gears at cruise. How fast are you cruising? Are you not using 5/6 gears??

4.10's in 6th gear cruises at 74 mph at 2000. Speed limit in most states highways (65-70). So your logic there makes no sense.


b body cam is 191/196. .418/.430" 111 lsa. Thats a babt duration cam. Fbody lt1 is 202/207 .450/.460 116. Tpi L98 was around 207/213 .415/.430 117 i think it was. Lt1 is much closer to tpi cam but abit more lift WILL be beneficial.

Phoenix'97

This is all I can ask for. This topic has drawn much hostility and many take offense when I am not persuaded to modify my car as per their suggestions. I drive my car year round and I have my own way to drive, so there are areas where I feel there can be improvements to make me happy with the motor in a stockish form. The question then becomes whether or not I have it right in my mind with the idea of using the TPI intake to satisfy this goal.

Yes, I realize that a simple change of the gear ratio may be all the modification that I need as far as easy thrills from the green light. However, even watching the youtube video from Street Lethal, I don't rev my motor that high! I would prefer to shift by 5000 RPM and have the torque come on sooner rather than later. So this is why I keep butting heads with others. After ten years of owning my car, I have developed my own driving style and I would prefer not to change it for the "fun" that I seek. The TPI intake once again seems to be a perfect match. So, I am really thinking I am going to go for it. I just need to figure out the camshaft since I am thinking I want more of a tow cam and it should be able to produce power up to 4500 - 5000 RPM.

Phoenix'97

I am currently using fifth gear as my "overdrive". I have encountered problems where on light inclines on the interstate I am forced to shift down from sixth gear to fifth, since my car lacks the torque under 2000 RPM to maintain speed. So, now I drive using fifth gear and set the cruise control. This started my desire to find a way to bump up my low end torque to address this issue. I used to be an 18-wheeler truck driver so I know all about downshifting to compensate for steep inclines, but I am not hauling a trailer and these are very minor gradual inclines where the car requires a downshift. It should not require a downshift on such a minor grade!

At 75 MPH in sixth gear I am hovering just above 2000 RPM when cruising. I seriously doubt that with a 4.10 gear ratio I will be cruising at 2000 RPM! That online calculator is not entirely accurate, either that or my speedometer is off!

Yeah, but the B-Body cam is spec'd to have similar performance to the F-body/Corvette LT1 camshaft, the B-Body cam merely produces more torque sooner. It would make perfect sense that a camshaft meant to propel a heavy Caprice/Impala or Fleetwood wagon giving them the same EPA fuel mileage rating as the F-Body and Corvette, would be excellent for a lighter weight F-body and even a Corvette driver wanting more down low torque! Then to pair this with the TPI intake on the LT1, they should compliment each other nicely! Do I have it wrong?

Abubaca

iTrader: (3)

Once again I agree with what you're saying, I just don't think it's gonna do what you think it's gonna do. My point being I could build you a mild LT1 with a 3.73 or 4.10 geared car, tell you it was a TPI...and I don't think you'd notice the difference without driving them back to back. I just don't think your "butt dyno" will be able to tell the difference, even when on paper, technically you will have achieved your goal.

I really think it's a cool idea, and it's the very essence of hot rodding, so I'm here to help. I just don't think you'll be happy with the outcome, or at the very least, you won't have really gained anything.

Phoenix'97

That is the risk I am taking! I won't know until it is done. However, if I can notice that my car has a hiccup in it's ignition, if I can notice subtle noises or feel subtle sensations that are not healthy from the car, I have confidence that I will be able to tell what changes have happened with a different camshaft and a different intake manifold. WILL IT GIVE ME WHAT I WANT? I hope so! My goal isn't to make this motor compete with the newer Camaro and Corvette, so whatever the result, I am consigning myself to it. At least it will be something to brag about having and it will make a nice picture to show off!

I do, however, need to get behind the wheel of a TPI car and just get an idea of how the intake works. A cheap thrill, pricey thrill, having the car pull hard to around 4000 RPM or so is really all the fun I am looking for. I just hope to piece together the right parts to make it happen.

Orr89RocZ

iTrader: (20)

Something is wrong on your end. Math is math, 25.7 inch stock size tire and those ratios it is what it is. Might want to verify the gear you have and the tach. Usually factory rev limit is 5800 not 6500 so that might be a sign your tach is off.

75 with 3.42's in 6th gear is 1670 rpm.

I honestly dont think the tpi intake is gonna solve that cruise on incline problem. Tpi builds torque in the 2800-3200 rpm range with a high peak. Below that its not gonna be noticeable from what i've seen on the dyno. But we typically dont pull below 2500.


B body cam being shorter duration and lift will be down on power everywhere.

You need more power to cruise at low rpm or more gear.

Tpi will give you better pants feel when going wot off idle once you get into that 2800-3200 range. Lt1 will feel continued pull all the way to redline. Tpi will fall off after 4200-4500 depending what intake runners and base (stock vs aftermarket)

aliceempire

iTrader: (14)

I didn't comb the whole thread but.... why not just leave well enough alone? You want more performance but you don't drive it for performance. So why make any changes? Not being sarcastic or anything of the like.

Abubaca

iTrader: (3)

Agreed.

My car is a 383 with an extensively ported TPI, and relatively small but efficient heads. ....with only 3.27 gears, it's an instant explosion of laugh inducing torque! ...and the whole ride is over by about 5000!

Phoenix'97

Well, if you were to look at the maintenance history on my car you would SWEAR these shops were intentionally milking me for more money while deliberately screwing my car up. This is most apparent with my Jasper reman LT1, but there will come a day when I get the whole motor reworked and hopefully that shop will be honest and fix my motor up right the first time. I don't think the tach is off but I do wonder about my speedometer. I do have the WS6 package with 17 inch wheels, not the 16 inch wheels!

I have been given plenty of torque graphs comparing the L98 with TPI intake against the LT1. Yes, I am aware that the TPI intake won't add to the off idle torque I am seeking, this is where the camshaft comes into play and where I should utilize a tow/mileage cam. This is why the B-Body camshaft seems like a good choice for a stock GM cam. I have checked out B-Body forums where guys have interchanged the cams in Vortec motors and their LT1s, and from my take on it, there isn't much difference short of the obvious lower torque production from the B-Body cam. However, I need to compare this information with what you say...

Well, if the B-Body camshaft is out of the question, I am thinking a custom grind now maybe based on the B-body? What about the ZZ4 camshaft?

Well, based on grumpyvette's site,
http://garage.grumpysperformance.com...ith-tpi.10494/

An extrude honed factory TPI intake with big tube runners seemed to produce the ideal torque curve with a 383 stroker. I realize my set-up won't be anywhere near this torque curve but it gives me some insight into how it would behave, a bit more continued torque than with stock. I could be wrong! Anyways, I wish to capitalize on that peak torque curve, so this is why the TPI intake is so appealing to me granted my driving style and where I am seeking the torque to kick in. Again, I need to solve the off idle torque problem and still be able to have power production within the powerband dictated by the TPI intake and by my criteria.


Well, all of the above should give you some insight into what I am looking for. The torque production of the stock LT1 does not do anything for me, but then again I drive the car wrong for the powerband it was designed for, for the powerband of the GM copy of the TPIS miniram intake manifold! It makes sense that I swap a TPI intake onto my LT1 to get to enjoy the powerband that I spend the most time in and one that is safe for daily driving/non-racing conditions. Just for me to have my smile without having a high horsepower beast or a stroker motor! Just a motor that is something that GM might have made had they not used the TPIS miniram intake on the LT1.

Orr89RocZ

iTrader: (20)

I just think with the long runner intake the torque curve shift will not be that noticeable, goin to the smaller cam. I actually think it might reduce power slightly. I think the concept of lower duration is good but i'd do it on a more modern lobe with abit more lift. You'll get faster valve motion and when timed correctly, you will see more power and torque everywhere. Its basically what the engine masters challenge was all about. Average power curve and they find fast valve motion is key to getting lower rpm power up

Orr89RocZ

iTrader: (20)

Heres a heads cam bolt on tpis tpi system on a stock bottom end L98. Torque curve kinda surprised me being as flat as it was. 351 trq. It was down on power over what i thought it would make but seemed to have more blow by than i expected so might be why it was down. But torque was pretty good for a hot cam 218-228 .525" 112 lsa cam. Drove like stock actually. And this is an automatic trans which is 10-20 whp less than a t56

Did another fresh rebuilt L98 all stock parts but a 218/224 comp cam and it only made 226 whp i believe it was. 309 trq. The tpi system didnt seem to respond much with the cam on stock heads like i thought it would. Its torque curve was much more peaky however and was rather low at the start of the pull. Could not pull it below 2700 rpm or it would downshift.

Phoenix'97

Now you lost me. Do you mean power as in torque or power as in horsepower?! I don't want to get too caught up in worrying about more power production to compensate for some that may be lost with the smaller cam. Honestly, this 1991 Corvette with a reproduction LT4 cam on 1.5RRs (an LT1 camshaft), seems pretty nice in this video.

After reading his parts list, I am now reconsidering long tube headers optimized for low end torque and just sticking with my aftermarket Hooker shorties currently on the car, even reconsidering any modifications to my exhaust, just keeping it a y-pipe to a cat-back. I do think I will benefit from Dart 180cc heads that are not altered.

So, the camshaft issue is still up in the air as I don't know how to go about this.

1. A custom grind tow/mileage cam with more lift
2. A ZZ4 style camshaft
3. A Crane 227 camshaft
4. Screw it and stick with my stock camshaft
5. Screw it and try using a B-Body LT1 camshaft

Orr89RocZ

iTrader: (20)

Power as in both trq and hp

Phoenix'97

Okay. Hopefully I make a good decision when the time comes to execute the build.

Abubaca

iTrader: (3)

I ran my TPI for years with a zz4 cam, headers and a 3.27 gear. First with a 2200 stall, then a T5.

Great set up in my opinion. -although I would've like to have seen it with a modern cam/lobe of similar spec.

Orr89RocZ

iTrader: (20)

I'd prolly just do the tpi intake for now and see if you like it. Then worry about the cam

Bow_Tied

iTrader: (1)

Glad I mentioned it then, I hope it works for you when the time is right. Give Paul a shout and he might have some suggestions that will help future proof what you do now for your later goals, as much as is possible.


When I was typing before I thought you had an LT1 in a 3rd gen, but I notice now your profile shows a '97. Is this a stock '97 LT1/T56/3.42:1 car? What size tire? Apologies if I missed that info.

Phoenix'97

I appreciate your comment, and thank you!

Yeah, I am the odd ball in this forum but it is not easy to find anyone willing to have this discussion about swapping a TPI intake onto a second gen LT1. The car is mostly stock, some replacement aftermarket parts here and there. The tire size is 275/40/17.

Phoenix'97

Yeah, I think I am going to have to talk to a custom grinder about my application and see what can be done. I keep forgetting advice I have received in the past, they make better camshafts now and I really should look into it before buying off the shelf outdated cam designs.

Well, I want low end grunt and I want it to compliment the TPI intake, maybe a little bit of a ZZ4 or maybe a little bit of a Crane 227. As far as addressing my concerns about fuel economy, maybe the tuning on the car paired with conservative driving will give me what I seek. So, I think that takes care of the camshaft question! I thank you for your comments!

Yeah, I won't have to tear apart the motor to put the TPI intake on it, but it will need a Dyno Tune along with the customization work to get it to fit. Ah well, it's a small price to pay before I have the camshaft put in, to get a feel for the car with the new intake on it and to compare mileage averages after the install. Thanks for the comments.

Orr89RocZ

iTrader: (20)

Crane 227 has been a proven performer. B body and f body alike. Something like that on a modern lobe design i think will do great

Street Lethal

iTrader: (16)

Listen to me, it's not about needing to rev the engine higher, as you control RPM with the stick shift. You need to understand how gearing works in conjunction with RPM and horsepower. The video I provided was to show you that swapping to 4.56 gears with a six speed is very common, and doesn't really hurt drive-ability. However, that was not meant to imply for you to shift the way the person in the video was shifting, he was doing that because that is what the LT1 intake allows for over the L98 intake. You can shift at any RPM you want to, you can keep it below 5000-RPM if you so choose to, it doesn't change the fact that the gearing will move you out much much faster from a stop light, which is what you said you wanted, not to mention move you out much faster at any RPM below 5000-RPM over the gears you have in there now. You're getting too caught up with fairy tales. People used to compare L98's and LT1's thinking a few horsepower really made the difference. It was gearing and stall speed that made the difference with the majority, as L98's coupled at a lousy 1500-RPM stock, and were lucky to flash up to 2000-RPM. The only reason why TPI's were considered low RPM's engines is because they couldn't breath, just like the BOP engines from the 70's, they were "torque motors" because they couldn't breath and were capped at 5500-RPM because of it. If you have your heart set on a TPI intake then go for it, I run one myself, and mine see's over 6000-RPM. But mark my words, you'll be disappointed when all is said and done. You're in New York I see, let me know if you're around the New York City area, I usually head back there every other weekend, and might be able to help you out one weekend...

- Rob

Abubaca

iTrader: (3)

Again, I agree with pretty much everything Rob just said.

You don't HAVE to shift a 4.56 geared car at 6500

Gears will provide mechanical advantage at ANY RPM you choose to run the engine.

People get caught up in the numbers...

TPI being a "torque" intake because that's really all it could do.

....fairy tales....being disappointed, etc. etc.

You gear/stall/set up your car for a TPI to make it driveable, because that's the intake you have. You don't have the car already set up -and then go ADD a TPI to change how the car performs. Much MUCH easier to set the gearing/shifting/cam up for the LT1 rather than make the TPI work on TOP of an LT1.

in 2018, anyone running TPI is doing so because of budget, originality, or nostalgia. It's not really a good performance intake.

Phoenix'97

I don't want this discussion to change topic, which it could very well be at risk for, but basically, the TPI intake is the next best thing to getting an LS intake put on my LT1. I have explored what it would take to do such a thing but I ran into a brick wall when the engine block to make it possible is only a SBC that isn't offered in a version with reverse flow cooling like the LT1. So, it was horribly disheartening to say the least...
http://www.superchevy.com/how-to/pro...-crate-engine/

http://www.hotrod.com/articles/hrdp-...own-ls-engine/

I don't have the resources to pay for someone to specially make me heads that will use the LS1 intake, the cost would be prohibitive to say the least, I imagine! So I am stuck trying to fabricate a TPI base to fit on my LT1 heads! Too bad GM doesn't offer a special head for the LT1 like the SBC Fast Burn heads. So, for the sake of optimizing low end torque, Dart 180cc heads that are unaltered should have to do!

For the type of driving I do, the TPI intake seems like the best route. I am not willing to sacrifice my highway mileage to boost mechanical advantage from a lower gear ratio! There is no need to zip to 5000 RPM in too much of a hurry. The slower acceleration I get from my factory 3.42 is sufficient enough, but it's the slower pull to 5000 RPM that I am seeking! Call me crazy!

Phoenix'97

Before I was advocating that I put a TPI intake on my LT1, I was looking at camshafts and I was considering just throwing on this camshaft and being done with it. Then my quest to modify the motor to better suit what I was looking for and wanting eventually took me to the TPI intake with some google search referencing lower end torque, and my curiosity on how to build a V8 motor for optimal fuel efficiency.
https://itstillruns.com/build-chevy-...e-7988109.html

Then I started worrying about the right camshaft choice that would work well with the TPI intake and not result in fuel economy loss, something that would work with 1.5RRs. I am not sure if the Crane 227 can work with 1.5s, everyone is using 1.6RRs that I have read about, so this is where I come full circle with the advice to talk to a custom cam grinder for my application. I am trying to have my cake and eat it too, so with the balancing act I may be able to do it, including a good tune!

bjankuski

I just want to point out that the reason an LS1 intake works well is because it runner length is optimized for power band from 2500 RPM to 6500 RPM and that is done with runner length. There is no magic to an LS1 intake other then it has a runner length designed for that RPM band. The closest intake design to the LS1 design as far as runner length is concerned is either the Superram intake, HSR intake or the FIRST. If you want the LS1 intake look at those to and see how to graft them on to a LT1. It should be fairly straight forward.

Orr89RocZ

iTrader: (20)

This is confusing me lol. You dont want a fast pull to 5000 but you want more torque for stop light to stop light so that implies a quicker pull in short rpm span

Gears amplify torque to the tire. You get faster acceleration that way. That leverage makes low power feel like alot more
Only way to improve current acceleration with the 3.42's is to add alot more power. But its gonna take away your mileage

Phoenix'97

This is where I confuse everyone with my choice of words! IF I use a TPI intake paired with a custom grind of the Crane 227, AND use a lower gear ratio than my stock 3.42, I am going to zip to 5000 RPM in a heartbeat, am I not right? This is what I am trying to avoid! Does this make sense?

Phoenix'97

Yeah but at that time I was looking into throwing on a truck LS intake like the Chevy Trailblazer intake to help improve lower end torque. Again, I don't see how I can fabricate such an intake to work on my SBC style heads with reverse flow cooling! The only way to do it is to use LS style heads on my block but this requires some expensive one-off customization! The TPI intake by this point is much better and cheaper to modify to get it to work on my LT1.

Hey, I am not complaining, the TPI is perfect for my driving style and I am sure I will be happy with it's torque curve before it starts to drop off by the time I shift.