TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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Ive got a 91 z l98. The car has 53000 miles. If you have read about any of my other posts then you will know that I had a factory replacement short block in december of last year and that recently because of midas, the car is no longer "original paint, fenders, etc." with this being said ive decided since im planning on keeping the car for a long time maybe its time to start making some mods to the car. I just wanted to get some opinions on what and where should i start. the car is stock. and im on a budget build meaning either i buy a part and pay to have it installed or just save up to buy lots of parts then save for installations. I appreciate your comments and opinions in advance.
Part No. - HT-CAM92 - Ram Air Hood - $510.00
Part No. - N/A - Ram Air Box And Filter - $210.00
Wheels
Chrome SS 10 Spoke Wheels
American Racing Series No. 329
American Racing Series No. 333
American Racing Series No. 628
American Racing Series No. 629
Thanks in advance
Kevin
i've been thru modding my L98 so far from stock tpi to holley stealth ram. From my experience here's some advice.
suspension mods are good...but 219 bucks for lower control arms is not...stay away from edelbrock on that one...you can get good spohn ones for lots less than that. 115 for basic set...price goes up on from there.. shop around you can get good used ones for cheap.
I'm running mostly spohn stuff. i like it all so far. i have their adjustable torque arm...nice piece for 400 bucks i spent. do you need it? not really on a stock car... so i'd stay away from a torque arm at the moment if you dont race alot.
a good investment is shocks and springs...i went with eibach prokit...dropped the front almost 2 inches i'd say and the rear about 1 inch. very nice looking stance and handling but works good on the drag strip too.
Adjustable shocks are a nice feature to have..taylor your ride quality from drag racing to road racing. I got tokico adjustables for 400 bucks new on ebay from a good seller.
I got the power and amp pulley set from march..aluminum crank and steel alternator... very nice kit for 100 bucks from thunder racing. definately felt better throttle response and maybe gained some power..sorta felt like it at the track judging by the numbers
aluminum driveshaft may make some improved throttle response but i'm not sure getting a inland unit for 400 bucks is a good investment. stock LS1 fbody shafts work well for 100 bucks and are aluminum. they hold decent amount of power too
As far as engine mods, i went with hooker headers/ypipe and flowmaster exhaust... then switched to a custom catback with chambered tube muffler...didnt see a huge difference in power/ET's at the track but the sound is much better now. edlebrock headers arent bad and if you have dual cats and want to keep them, they are the only option... else i'd go with hooker as they seem to fit better from what i've heard..thats why i went with them. Plus their y pipe seems to be very nice compared to other manufacturers
muffler doesnt really matter much..go with what sounds best for you
I now have holley stealth ram on my L98 and the gains were HUGE. MUCH better than stock TPI. Now if I would have upgraded to runners/base over stock, i probly would have seen good gains as well but would have spent more money. Stealth ram is best bang for buck if you dont need to keep emissions. if you do, then keep TPI and run ported SLP runners and base of your choice...edelbrock is nice as its cheaper but could use some porting. you'll see good gains with some minor tuning.
Other than that i'd suggest upgrading gears to 3.42, and putting in some kind of converter... I run a Edge racing converter for 550 shipped, and custom build to my specs. 2800 stall speed. by far the best investment i made..next to the stealth ram. really wakes the car up from any speed. punch the gas and it swings the rpms up and takes off. at the strip, its why i can run low 13's at 100 mph on low 1.7 60 foots.
You might want to check out summit racing for these parts. In most cases they are cheaper and they only have a standard 10.95 handling fee, free shipping in most cases
agreed, summit can be a good place for large orders on parts...since they only charge 10.95 for handling for smaller items and only charge a little fee for oversized stuff liek wheels/tires
good place for ignition stuff, gears, some suspension, some intake/engine stuff, etc
Ill have to look into the headman headers, theyre not listed in the summit mag i have well the air compatable ones anyways, and yeah summit is like a 40 min drive for me cause theres one in mcdonough, ga so thats really convieanant. thanks for the info so far.
kevin
89rocz,
are you saying that a later fbody driveshaft would fit my car?? if so that is reall interesting news to me, and also if that is so, what years come with aluminum driveshafts, maybe i can shop the local salvage yards for one. thank for the help
kevin
yes, later year fbody shafts will fit. i do believe all 98+ cars came with aluminum shafts, but not sure about the 93-97's. Some probly had them in 96-97 from what i hear. 1LE thirdgens had the aluminum shaft as well.
do a search for 4th gen aluminum driveshaft and lots of threads will come up
hey thanks for the info... cause if i can find one at a salvage yard i could save a lot. id just like to have one cause i hear their lighter, and plus mine has surface rust so would like to have one that is clean. thanks
kevin
i have a question about ram air boxes.... i would really like to get the ram air hood for my car. rather than paying the extra 200 bucks could i pull one off at a bone yard for my car and if i could what year t/a/birds will fit my car? tia
kevin
i dont think any will fit...the only ones i can think of is a LS1 car that has factory RAM AIR... that you could have a chance of finding but i'm not sure it will fit
definately not. does a covnerter really wake the car up that much? i don't really understand what a looser converter will do for you or how much it impacts regular driving.
it does wake the car up alot! it more effectively multiplies torque and puts the engine into the power band quicker.
stock stall is like 1600 rpms. meaning, if you floor it from idle, the rpms will rise to about 1600 rpms and then the converter will tighten up and start turning the transmission. so the engine effectively is applying power that its making at 1600rpms to the trans which goes to the rear tires, and the car starts accelerating at that point.
add a 2800 stall like i have, and do the same. Floor it from idle, it will rocket rpms up to 2800 before it starts tranfering the power from the motor to the trans. There is a BIG power difference from 1600 to 2800 rpms on a TPI motor. The car now starts accelerating from 2800 rpm rather than 1600.
This is how some guys go from 1.90 60 foots down to 1.70 60 foots with just replacing the converter.
but its not just from idle. while rolling from 45 or any speed/mph in drive, you stomp on it. a stock converter car will just downshift gears and go from whatever rpm its at in that lower gear. A stalled car will flash up rpms while it downshifts so again, your starting acceleration with more power in the "meat" of the power band
You'll be VERY impressed once you convert over to a higher stall converter over stock. I know i was
Shift exstension is one of the major things a converter does. Meaning - the RPMs don't drop off as drastically after an upshift. In my LS1 car, it shifts at 6400-6500 and drops off to maybe 5200-5300 on a shift. With a stock converter it would lose 2200-2500 RPM on a shift. I peak at 6200, so I am making much better power to accelerate the car at say 5300 vs 4300 RPM. It makes the pull through the gear more seamless. You don't really feel the car fall off and pick back up again when it shifts. It's like a continuous pull from the instant you go WOT.
I'm a lil torn between a manual swap and playing with the auto that's in it.
I'm a twisty driver as much as a straightline racer, i'd like to autocross the car as well as dragrace it, but mostly it sees spirited highway and street driving.what is the downside of a higher stall converter in daily use, and does it have benefits over a manual trans other then consistancy?
Is there a way to cheaply modify a 700 r4 to make it shift swiftly and be in the best gear for acceleration?
how would i know what converter to buy that is one item i have no knowledge of and dont want to buy one i dont need. im trying to build my car up for me to enjoy even more when driving. i dont street race and dont plan on goin to the track, but everyonce in a while id like to get on it. more importantly i want heads to turn when i drive by. what are your opinions on first tpi? im considering buying their setup rather than buying edelbrock and slp. i mean in stead of buying 700 bucks worth of parts, i could spend an extra 150 or 300 if i want it painted, and i could have a brand new ported top end. their just so many different possibilities that i just cant make up my mind. tia
kevin
FIRST TPI is better than any aftermarket TPI stuff from TPIS/Edelbrock/SLP etc. their stuff is bigger and better and allows for more flow. probly comparable to a HSR for that matter for most setups. it willl still be good for cam/heads upgrade too for more power. If you want a serious TPI car, then go FIRST. you still can make good power off of other TPI stuff but good porting and port matching should be done to get the full benefit of the parts. they leave room for alot of work so take advantage. If you dont want to spend money on having it done, or do it yourself, then get First or HSR/Superram/miniram.
For a street car that doesnt see much track use or racing of any type, then i'd stick with a 2400-2600 stall. TPI cars make low end torque and dont need a real big stall so something like 2800-3000 is perfect for a car that has bolt ons and sees track time. Still very streetable if you keep the lockup feature like stock converters. once you hit a certain cruising speed, the converter locks and drives like stock. you'll never know its a higher stalled converter till you get on it.
good deal, any recommended brands on the converter, ill start looking through my summit mag tomorrow. im really impressed with first tpi, and more than likely will save up and buy their setup, the only thing i dont like is the mono blade tb, and thats just a personal preference, i have a bbk 58 mm sitting in the box i would like use one day and also if i do get the first tpi im gonna have to figure out what air box to get cause the fitting i have now is for the oval tb unit. but like i said eventually will have ram air just because i realy like the hood on the camaro. and all these bolt on might take a year plus for me to get but i just want to have a good plan to go by. im happy with the rearend ive got not plus it has factory posi traction (3.23 rpo g92 performance rear axle) after i do the top end then i plan to get headers and borla exhaust, and then eventually figure out which camshaft to get. but that later down the road. i appreciate all your help and info.
kevin
i have a Edge racing converter. Ordered directly from them setup to your specs. its a efficient 9.5" unit and 2800 stall. I love it. Summit carries the basic stuff like TCI, B&M and etc. they are cheaper converters because they are abit cheaper quality. some have had good success with them. But you definately shouldnt skimp out too much on a important part. My converter was well worth the 550 shipped.
the only probly with the First TPI with 58 mm blade TB, is on a stock car its gonna have poor air velocity and have abit of hesistation off idle. stock heads/cam L98s dont need a lot of air but more than stock TPI can give them. if you put on an intake with a huge amount of air flow with a big TB, you'll have some off idle problems that you can get rid of with some good tuning
lt4 hot cam possibly is an option, but i dont know much about them all i know is i want an agressive one but still have to remain emissions legal.
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also one more question before i leave.... hedman headers or edelbrock? those are the only two that i know of that make emissions headers for my car that will adapt to my dual cats.
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Last edited by tranceemotionz; 10-18-2007 at 11:41 PM.
Reason: Automerged Doublepost
not sure how far along you are in your build, but i see you were looking to get an edelbrock strut tower bar? i had one on my iroc, got maybe 500 miles but now the car is dead and im parting it out. send me a personal message if youre still interested and we can work out a deal
blower,turbo,or nitrous. turbos are fun on a tpi. there is a guy in car craft magazine with a stock tpi with a edelbrock base and a turbo set up running 10.74's @13x mph wild *** car. the engine is a stock *** 350 out of a 70's truck. trans is a turbo 400 and rear is a ford 9 incher. turbo setup shouldn't be that hard to achieve on a 3rd gen. hell i bet you can make a setup for under 500 bucks.
__________________ 86 Omni GLHT non vtec. almost stock.
turbonetics 50 trim and some bolt-ons.
For autocross, go T5/T56. Autos play havoc, with their up/down shifting, when THEY want to, not when YOU want to. Unless you put in a full manual valve body in your auto, go manual for autocross.
yeah first tpi doesnt even have an adapter for a twin blade throttle body, and the reason is they say it restricts their system which is understandable i guess. ive thought about manual transmissions but if i ever get one it will be on another project car. what are opinions on a shift kit? or would the coverter be enough that i need, except for the zr-1 vette, would a pair of aluminum heads off a 91 vette be compatible with my tpi? again this is another subject that im clueless on, head selection and camshafts. and solaris. i havent even started my build, im still trying to come up with a "build sheet" i guess you could say and buy one part at a time. budget builds suck. while im thinking about it has anyone third gen on here ever run the borla exhaust... im curious as to how aggressive sounding one is. wel thats all i can think of right now... so rocz would you say yes or no to the first tpi setup, or should i spend the 200 bucks less and get the edelbrock manifold, slp runners, and just have my plenum ported.... the first tpi flows 30% more than factory, and can handle up to 6200rpms, which is more than i would need but nice to know, runners are 1.75" inside diameter, and the tb flows 835cfm's, i guess thats good, i dont know the stats on the edelbrock/slp setup. thanks in advance
kevin
i tried that tb coolant bypass, and didnt notice any thing different other than the tb getting even hotter.. i have k&n's and plan to get an airfoil untill i get the first setup, dont have a clue about chip burning, and i guess the chip would advance the timing becuase mine is computer controlled, and eventually a shift kit. but step by step im getting my "parts list" in concrete. thanks for all your help.
kevin
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and what is AFPR? im guessing aftermarket fuel pressure regulator?
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Last edited by tranceemotionz; 10-21-2007 at 12:28 AM.
Reason: Automerged Doublepost
i'm gonna dissagree on tuning. I was running bone stock bin for my full exhaust L98 that had a Holley stealth ram on it and still ran very strong. Only used the fuel pressure regulator and base timing to "tune" it. it worked
However with some tuning to the prom, my driveability improved as well as some power. i picked up a tenth just from adjusting the timing curve abit in the chip and also leaned it out some as it was rich
point is with small modifications like ported TPI and exhaust, you can use base timng and fuel pressure to "get it close". depends on how well your car runs off the stock ecm/prom. my car was tuned well from the factory and was in good running order. If yours isnt, then more mods will make it worse.
i'm gonna dissagree on tuning. I was running bone stock bin for my full exhaust L98 that had a Holley stealth ram on it and still ran very strong. Only used the fuel pressure regulator and base timing to "tune" it. it worked
However with some tuning to the prom, my driveability improved as well as some power. i picked up a tenth just from adjusting the timing curve abit in the chip and also leaned it out some as it was rich
point is with small modifications like ported TPI and exhaust, you can use base timng and fuel pressure to "get it close". depends on how well your car runs off the stock ecm/prom. my car was tuned well from the factory and was in good running order. If yours isnt, then more mods will make it worse.
Changing from long tube to short tube intake runners, along with the other mods, I can see a need for PROM tuning.
First run of the season in my then freshly purchased GTA,15.1 1/4 et
Last pass of the season, after many minor mods, learning to launch, doing a good tune up and mainly a computer tune, 14.36 at 95 mph in a 3500 lb car. less then 200 in modifications, but 300 and change for tuning stuff, netted me 7 tenths and change. so yes i support chip tuning.
Oh and the other major thing i promote? suspensions mods. if you can't hook you can't go.
First run of the season in my then freshly purchased GTA,15.1 1/4 et
Last pass of the season, after many minor mods, learning to launch, doing a good tune up and mainly a computer tune, 14.36 at 95 mph in a 3500 lb car. less then 200 in modifications, but 300 and change for tuning stuff, netted me 7 tenths and change. so yes i support chip tuning.
Oh and the other major thing i promote? suspensions mods. if you can't hook you can't go.
You compared the first run of a season to the last...
Learning to DRIVE that car...how it launches, how it reacts, rpm limits/shift points, etc...I bet gained the most. Knowledge is power.
turbo setup shouldn't be that hard to achieve on a 3rd gen. hell i bet you can make a setup for under 500 bucks. 
