Engine upgrade questions...
Thread Starter
Supreme Member
Joined: Oct 2002
Posts: 1,042
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From: Oklahoma City, OK
Car: 92 Z28
Engine: 357 TPI (L98)
Transmission: 700R4
Engine upgrade questions...
I've pretty much determined that I want to go with a Stealthram/AFR190 combo, but I've got a lot of questions about it.
(I know this first question is kind of asked all the time, so if you want to ignore this question that's cool, I just know nothing about cams.)
1) It'll be a daily driver, so I guess I need what you'd call a "mild" cam. Definitely not wussy but not so big that there's no driveability. Obviously I want as much power as I can get out of the cam without making the car a pain in the *** to drive every day. I don't want a cam that puts all the power WAY up there, and not one that's all down low. Like around 3000-6000rpm.
2) I'll probably be going up to about 6000 rpm, so I'm worried about my engine. How concerned should I be about my pistons, rods, etc.? I won't be road-racing so I wont constantly be up at 6000 rpm, but I still want it to be reliable enough. The last thing I need is engine destruction. The motor was rebuilt about 18 months ago, but that was before I owned the car so I didn't supervise it. I know they put "better" components than stock, and obviously they're not 10 years old from when the car was built, but as far as how good they are I'm regarding them as stock-quality. How concerned should I be?
3) Deciding on the AFR190's still left a lot of questions. I have a '92 L98 TPI, which may be important information.
a) Do I need straight plug, angle plug, or what? (Which AFR part#, basically).
b) What's a heat riser and do I need it?
c) Do I need new lifters? New pushrods?
d) Do I need a hydra-rev kit?
e) Do I need to upgrade the springs that come with the heads? I hear they don't work too well at higher rpms.
4) Assuming I get a new mild cam, I'm guessing I'll need new rocker arms. Which ones should I get if I want them to be acceptable but not expensive?
Thanks for reading, guys!
(I know this first question is kind of asked all the time, so if you want to ignore this question that's cool, I just know nothing about cams.)
1) It'll be a daily driver, so I guess I need what you'd call a "mild" cam. Definitely not wussy but not so big that there's no driveability. Obviously I want as much power as I can get out of the cam without making the car a pain in the *** to drive every day. I don't want a cam that puts all the power WAY up there, and not one that's all down low. Like around 3000-6000rpm.
2) I'll probably be going up to about 6000 rpm, so I'm worried about my engine. How concerned should I be about my pistons, rods, etc.? I won't be road-racing so I wont constantly be up at 6000 rpm, but I still want it to be reliable enough. The last thing I need is engine destruction. The motor was rebuilt about 18 months ago, but that was before I owned the car so I didn't supervise it. I know they put "better" components than stock, and obviously they're not 10 years old from when the car was built, but as far as how good they are I'm regarding them as stock-quality. How concerned should I be?
3) Deciding on the AFR190's still left a lot of questions. I have a '92 L98 TPI, which may be important information.
a) Do I need straight plug, angle plug, or what? (Which AFR part#, basically).
b) What's a heat riser and do I need it?
c) Do I need new lifters? New pushrods?
d) Do I need a hydra-rev kit?
e) Do I need to upgrade the springs that come with the heads? I hear they don't work too well at higher rpms.
4) Assuming I get a new mild cam, I'm guessing I'll need new rocker arms. Which ones should I get if I want them to be acceptable but not expensive?
Thanks for reading, guys!
Last edited by jamesbob02; Sep 25, 2003 at 09:17 PM.
Member
Joined: Sep 2003
Posts: 273
Likes: 0
From: Indianapolis, IN
Car: 87 Firebird Formula
Engine: 305 LG4
Transmission: Auto
What exactly are your goals for this car?
You say you want a daily driver, but will be taking it up to 6000...
So are you planning on drag racing it too? If so what sort of time/MPH range are you looking for...
Is the car an automatic or a manual?
What mods does the car already have? Exhaust, intake, chip?
You say you want a daily driver, but will be taking it up to 6000...
So are you planning on drag racing it too? If so what sort of time/MPH range are you looking for...
Is the car an automatic or a manual?
What mods does the car already have? Exhaust, intake, chip?
Thread Starter
Supreme Member
Joined: Oct 2002
Posts: 1,042
Likes: 0
From: Oklahoma City, OK
Car: 92 Z28
Engine: 357 TPI (L98)
Transmission: 700R4
My goals are to eventually be in the 12's. Like most guys, I'd like a daily driver that can compete with corvettes and smoke your average LS1. I want that surprise on the face of the guy who was sure his newer Z28 was faster than that old thirdgen! You know what I mean.
I guess I'm showing my lack of experience, but I figured that mid-to-higher rpms is what the stealthram wants, as compared to the tpi I have now. I know a lot of guys put this combo on their cars, and they're not all strictly drag cars I'm assuming.
If I'm wrong, tell me what I need to do and I'll do it!
The tranny is a 700r4 for now, but eventually it'll be a T56. That could be anywhere from 6 months to 2 years away, though. I honestly don't know what gears I've got in the rear. The guy I bought it from said they were 3.73 or 4.11, but I dont think it feels that high, and the tag is still on it that says 2.77. I thought stock for my car was 3.23 or something, though, so I really don't know. I'll try to take off the diff cover and see what I've got this weekend.
As for mods:
(current)
- NO emissions equipment
- Hooker catback (no cats)
- Hooker 2055 shorties Jet-hot coated (putting in this weekend)
- Performance Distributors (DUI) Ignition module and coil
- MSD cap, rotor, super conductor wires
- Alston SFC's and TDS Wonderbar (putting in this weekend)
- TB coolant bypass
What do you think? Thanks.
I guess I'm showing my lack of experience, but I figured that mid-to-higher rpms is what the stealthram wants, as compared to the tpi I have now. I know a lot of guys put this combo on their cars, and they're not all strictly drag cars I'm assuming.
If I'm wrong, tell me what I need to do and I'll do it!
The tranny is a 700r4 for now, but eventually it'll be a T56. That could be anywhere from 6 months to 2 years away, though. I honestly don't know what gears I've got in the rear. The guy I bought it from said they were 3.73 or 4.11, but I dont think it feels that high, and the tag is still on it that says 2.77. I thought stock for my car was 3.23 or something, though, so I really don't know. I'll try to take off the diff cover and see what I've got this weekend.
As for mods:
(current)
- NO emissions equipment
- Hooker catback (no cats)
- Hooker 2055 shorties Jet-hot coated (putting in this weekend)
- Performance Distributors (DUI) Ignition module and coil
- MSD cap, rotor, super conductor wires
- Alston SFC's and TDS Wonderbar (putting in this weekend)
- TB coolant bypass
What do you think? Thanks.
Member
Joined: Sep 2003
Posts: 273
Likes: 0
From: Indianapolis, IN
Car: 87 Firebird Formula
Engine: 305 LG4
Transmission: Auto
See now, the 12's is what's important here. My goal is low-14's to mid-13's. That's a big difference in horsepower requirements.
For instance, with my 87 'Bird, I'll probably need around 320 HP to go around 14.2, 370 HP to go 13.5, 450 HP to go 12.8, and nearly 500 HP to get into the low 12's. You can check out these approximations here http://www.fasttimesperformance.com/analyzer.html
Found this article that seems to accomplish what you want.
http://www.gmhightechperformance.com...holleystealth/
Looks like it would give you good power and a broad power band, which should give you good streetability.
The cam is a custom grind flat-tappet hydraulic from Competition Cams (218*/228* duration at .050-inch lift).
I'd be interested to see what the lift is for this cam. I'd contact the magazine, or see if you can find part 1 of the article. That's pretty conservative duration for the amount of power they're generating.
For instance, with my 87 'Bird, I'll probably need around 320 HP to go around 14.2, 370 HP to go 13.5, 450 HP to go 12.8, and nearly 500 HP to get into the low 12's. You can check out these approximations here http://www.fasttimesperformance.com/analyzer.html
Found this article that seems to accomplish what you want.
http://www.gmhightechperformance.com...holleystealth/
A recap of the test vehicle's combination of parts shows the IROC to have a 9.8:1 compression 355ci small-block with box-stock TFS G1 heads. The cam is a custom grind flat-tappet hydraulic from Competition Cams (218*/228* duration at .050-inch lift). Fuel is added by flow-balanced 24-pound SVO injectors. A homemade ram-air system utilizing K&N filters feeds the engine through a modified mass airflow sensor and 52mm BBK throttle body. The exhaust is comprised of 1 5/8-inch Hedman shorty headers a single 3-inch Race Series Dynomax muffler with dual outlets. The TH350 transmission, TCI 10-inch stall converter, stock 3.23 rear, and Auburn limited slip unit rounds out the drivetrain. Traction is supplied by 26x11.5 ET Streets with the only weight reduction coming from skinnies up front.
...
Any question whether the intake was going to work or not was put to rest during the initial three-minute test drive. The tachometer zinged to 6,000 rpm and unlike the TPI combination, the StealthRam allowed the car to pull from any speed you dropped the accelerator. Although there seemed to be a slight reduction in initial throttle response, it was unlikely the StealthRam would like the same initial timing and fuel pressure as the TPI/SLP intake system it had replaced. Normally, a few changes would have been made to the initial timing and fuel pressure to help determine best guess settings before going to the track. Nevertheless, there was just enough time to tune it at the track if we hurried. So no time was wasted getting to Tuscola Motor Sports.
Less than two hours after completing the installation of the StealthRam, we did our first burnout. As soon as the car launched you could tell the tune was off. It felt sluggish throughout its first pass and it showed with a somewhat disappointing ET of 13.120 at 105.43 mph. Knowing a much better ET was there, the initial timing was increased to 12* and the car was allowed to cool before the next run.
On the second pass, an uncapped Mustang with the top of the carburetor visible over its fender line pulled out and staged beside the IROC. Three seconds after the green light the Mustang was four car lengths behind and that lead was stretched throughout the quarter. The IROC responded favorably to the change with an ET of 12.990/105.90 and literally set the Mustang on fire! Thankfully the driver, believed to be the victim of a transmission leak, was able to douse the Mustang's flames without injury to himself or the car.
...
Any question whether the intake was going to work or not was put to rest during the initial three-minute test drive. The tachometer zinged to 6,000 rpm and unlike the TPI combination, the StealthRam allowed the car to pull from any speed you dropped the accelerator. Although there seemed to be a slight reduction in initial throttle response, it was unlikely the StealthRam would like the same initial timing and fuel pressure as the TPI/SLP intake system it had replaced. Normally, a few changes would have been made to the initial timing and fuel pressure to help determine best guess settings before going to the track. Nevertheless, there was just enough time to tune it at the track if we hurried. So no time was wasted getting to Tuscola Motor Sports.
Less than two hours after completing the installation of the StealthRam, we did our first burnout. As soon as the car launched you could tell the tune was off. It felt sluggish throughout its first pass and it showed with a somewhat disappointing ET of 13.120 at 105.43 mph. Knowing a much better ET was there, the initial timing was increased to 12* and the car was allowed to cool before the next run.
On the second pass, an uncapped Mustang with the top of the carburetor visible over its fender line pulled out and staged beside the IROC. Three seconds after the green light the Mustang was four car lengths behind and that lead was stretched throughout the quarter. The IROC responded favorably to the change with an ET of 12.990/105.90 and literally set the Mustang on fire! Thankfully the driver, believed to be the victim of a transmission leak, was able to douse the Mustang's flames without injury to himself or the car.
The cam is a custom grind flat-tappet hydraulic from Competition Cams (218*/228* duration at .050-inch lift).
I'd be interested to see what the lift is for this cam. I'd contact the magazine, or see if you can find part 1 of the article. That's pretty conservative duration for the amount of power they're generating.
Supreme Member
Joined: Jun 2001
Posts: 9,550
Likes: 5
From: Charleston, SC
Car: 91 Camaro Vert
Engine: 02 LS1, HX40
Transmission: 2002 LS1 M6
Originally posted by Keith_Indy
See now, the 12's is what's important here. My goal is low-14's to mid-13's. That's a big difference in horsepower requirements.
For instance, with my 87 'Bird, I'll probably need around 320 HP to go around 14.2, 370 HP to go 13.5, 450 HP to go 12.8, and nearly 500 HP to get into the low 12's.
See now, the 12's is what's important here. My goal is low-14's to mid-13's. That's a big difference in horsepower requirements.
For instance, with my 87 'Bird, I'll probably need around 320 HP to go around 14.2, 370 HP to go 13.5, 450 HP to go 12.8, and nearly 500 HP to get into the low 12's.
LMAO! dude, i hope you mis typed some numbers there!
with good driving, 320hp should put you in the 12s somewhere... you know, kinda like it does with LS1s....... now depending on other factors besides peak hp, it might be low 13s, but thats still alot faster then 14seconds.....
450 should put you in the 11s, no prob.
where the heck are you getting these numbers!?
Supreme Member
Joined: Sep 1999
Posts: 1,383
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From: Oakville, Ct
Car: 1991Firebird T/A
Engine: 350
Transmission: Modified Viper t-56
Axle/Gears: dana 44, 3.55
430 hp here and i'll let ya know oct 3rd what i do at the track...
here's my engine combo, its carbed however, but to give ya an idea...
ZZ3 shortblock
Trickflow 23* 64cc, cnc chamber heads (1300 from summit i belive)
XR288 cam- 236/242 dur at 050, 520/540 lift, 110 lsa..
hooker LT's
victor jr intake...
here's the dyno chart-
As far as driveability goes, its marginal on vacum, drives perfectly fine. so much for big cams being a pain in the *** to drive...
As for vacum, i wouldn't expect to see you go with anything higher than a xr276 cam or something close there of- so you'll be even better there.
Make sure ya get a cam to work with the 'puter too...
Transmision is also going to be of some concern of yours- an automatic is not going to be as tolerant of a bigger cam. I'm not experianced here, but most everyone will recommend a bigger convertor, so figuer that into your cost.
i run a WCt5 with a 342 rear, and its fine..
here's my engine combo, its carbed however, but to give ya an idea...
ZZ3 shortblock
Trickflow 23* 64cc, cnc chamber heads (1300 from summit i belive)
XR288 cam- 236/242 dur at 050, 520/540 lift, 110 lsa..
hooker LT's
victor jr intake...
here's the dyno chart-
As far as driveability goes, its marginal on vacum, drives perfectly fine. so much for big cams being a pain in the *** to drive...
As for vacum, i wouldn't expect to see you go with anything higher than a xr276 cam or something close there of- so you'll be even better there.
Make sure ya get a cam to work with the 'puter too...
Transmision is also going to be of some concern of yours- an automatic is not going to be as tolerant of a bigger cam. I'm not experianced here, but most everyone will recommend a bigger convertor, so figuer that into your cost.
i run a WCt5 with a 342 rear, and its fine..
Last edited by fb305svs; Sep 26, 2003 at 12:53 PM.
Thread Starter
Supreme Member
Joined: Oct 2002
Posts: 1,042
Likes: 0
From: Oklahoma City, OK
Car: 92 Z28
Engine: 357 TPI (L98)
Transmission: 700R4
Thanks for the replies.
Keith, yeah I don't think its going to be quite that tough to reach 12's. With the right traction and stuff, I should be able to get there with a little more than what LS1's come with, so 350 HP should get me there pretty easily, at least into higher 12's. I'm shooting higher than that for HP, though, because I'd like some room to work with and I know my suspension/traction isnt perfect.
I appreciate your looking up that GMHTP article, but I actually have both parts in print lol.
Anyways, like I was asking before, how concerned should I be about my internals? And will I need new lifters? Pushrods? Rockers?
Thanks.
Keith, yeah I don't think its going to be quite that tough to reach 12's. With the right traction and stuff, I should be able to get there with a little more than what LS1's come with, so 350 HP should get me there pretty easily, at least into higher 12's. I'm shooting higher than that for HP, though, because I'd like some room to work with and I know my suspension/traction isnt perfect.
I appreciate your looking up that GMHTP article, but I actually have both parts in print lol.
Anyways, like I was asking before, how concerned should I be about my internals? And will I need new lifters? Pushrods? Rockers?
Thanks.
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Member
Joined: Sep 2003
Posts: 273
Likes: 0
From: Indianapolis, IN
Car: 87 Firebird Formula
Engine: 305 LG4
Transmission: Auto
Anytime you change a cam you want new lifters. That's what the camshaft companies recommend.
Springs - depends on the lift of the cam.
Pushrods - don't know what comes stock.
I got the numbers here... so don't jump on me if they're wrong...
http://www.fasttimesperformance.com/analyzer.html
I was figuring for a 3500 lb car. HP at the flywheel not the wheels.
Not my car, but someone who's got some info...
http://www.personal.psu.edu/users/b/...rformance.html
Figuring 20% loss in the drivetrain he's putting out 345 HP at the fly wheel. Altitude corrected the ET would be 12.98 for his combo.
And of course, there's a lot of factors in ET's, his 60' times aren't to good considering he has DOT slicks on. So YMMV
Springs - depends on the lift of the cam.
Pushrods - don't know what comes stock.
I got the numbers here... so don't jump on me if they're wrong...
http://www.fasttimesperformance.com/analyzer.html
I was figuring for a 3500 lb car. HP at the flywheel not the wheels.
Not my car, but someone who's got some info...
http://www.personal.psu.edu/users/b/...rformance.html
My car Dyno'd 276.8 rwhp ~5200rpm and 317.7 rwtq ~2300 rpm.
Best time was 13.204 @ 105.83
Best time was 13.204 @ 105.83
And of course, there's a lot of factors in ET's, his 60' times aren't to good considering he has DOT slicks on. So YMMV
Supreme Member
Joined: Jun 2001
Posts: 9,550
Likes: 5
From: Charleston, SC
Car: 91 Camaro Vert
Engine: 02 LS1, HX40
Transmission: 2002 LS1 M6
Originally posted by Keith_Indy
Anytime you change a cam you want new lifters. That's what the camshaft companies recommend.
Anytime you change a cam you want new lifters. That's what the camshaft companies recommend.
unless its a roller cam... you can reuse roller lifters if they are in good condition..
flat tappets however must ALWAYS be replaced
Thread Starter
Supreme Member
Joined: Oct 2002
Posts: 1,042
Likes: 0
From: Oklahoma City, OK
Car: 92 Z28
Engine: 357 TPI (L98)
Transmission: 700R4
What's stock for my 92 TPI 350? I don't know whether I have roller or non roller camshaft and lifters. I do know I don't have roller rockers.
Member
Joined: Sep 2003
Posts: 273
Likes: 0
From: Indianapolis, IN
Car: 87 Firebird Formula
Engine: 305 LG4
Transmission: Auto
87+ are all roller cams (from what I've read.) You can change to flat tappets (you'll need longer pushrods), but roller cams give you an edge (less friction)...
Just make sure you get a roller cam, that your computer will handle.
Just make sure you get a roller cam, that your computer will handle.
Thread Starter
Supreme Member
Joined: Oct 2002
Posts: 1,042
Likes: 0
From: Oklahoma City, OK
Car: 92 Z28
Engine: 357 TPI (L98)
Transmission: 700R4
I don't understand what you mean by "get one the computer can handle", because basically any camshaft I get is going to require tuning, so is there a limit to what the computer can handle even with tuning? Or are you saying I should get a camshaft that will be kosher with the stock tuning? Just wanted to make sure.
As for the lifters, there's NO way I would go to flat tappets from roller.
Just to make sure, my lifters should be hydraulic roller, not solid roller, correct? Would this make a difference in my cam choice? Thanks guys.
As for the lifters, there's NO way I would go to flat tappets from roller.
Just to make sure, my lifters should be hydraulic roller, not solid roller, correct? Would this make a difference in my cam choice? Thanks guys.
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