TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
Welcome to ThirdGen.org!
Welcome to ThirdGen.org.
You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!
My car curently run's 12's, I'd like to hit 11's N/A but dont know if its got it in it. It was actualy built to run boost thats why the compression is only 9:1, I just cant aford the charger yet, lol
I did some tuning so it drives normal now and changed the gears to 3:73's, but never got it back to the track this season to see what it run's now, defenetly seat of the pants faster.
Stock W/C T-5 is comming out and I got a T-56 from a 95 T/A going in this spring, hoping to swing a 9" with 3:90's at the same time but will have to see how the $ is
This ad is not displayed to registered members. Register your free account today and become a member on ThirdGen!
Last edited by Hawk92z-TDZ; 10-29-2006 at 05:15 PM.
Sponsored Links
Registered users do not see this ad. Click here to register for free!
13.8 @ 104.25MPH. That was with a stock 305 TPI that was cammed, supercharged, and a 3:73 gear.
The car now has a 383 that I hope to have at the track next year.
Stock W/C T-5 is comming out and I got a T-56 from a 95 T/A
Selling this I would assume? I might be swapping from auto to 5spd so this would be a good starting point. From the 1/4 times you listed it seems this trans has held up with no problems? What did you use to tune your TPI?
well driven the stock L98's should be mid 14's. some i have heard doing lower 14's stock. several dozen cars doing low 14's with just a catback and k/n filters. those aint much in mods
what kills the 350 isthe auto trans and stock converter. my car with just converter/full exhaust on street tires with stock 2.77 gears went 1.89 60 foot and 13.89 at 97. slicks would have been deeper 13.8s probly 13.7s in good weather. they are strong motors, just need converter/tires to wake them up
a manual stock L98 will do low 14's cuz of the better gearing and ability to launch at higher rpms than stock converter in the autos. i am willin to bet a bone stocker with 3.42 gears and T5 on slicks/drag radials would have broke into high 13's well driven. quite possible on street tires it might have gone high 13's as well.
That's how it goes from the factory. SD cars can usually pull mid to low 14's MAF cars are usually high to mid. They supposedly switched to lighter pistons in the SD cars, and they didn't have the MAF restricting the intake. This combined with a better computer makes them 2 to 3 tenths faster on average (in stock, or close to stock form).
the 87-88s seem to be weaker than the 89-92's. mid higher 14's for the earlier L98's and mid lower for the 89+.
90+ did have lighter pistons or so but also a slightly weaker cam but on a tighter LSA so the power diffs might be minimal. 89 L98s are fairly strong tho. they are rated just 5hp shy of the SD cars. but from what i seen and my own experience, they are just as strong if not stronger than SD
1987 iroc
350 L98, ported stock heads edelbrock 1 5/8 headers with 3 inch catback system 2 chamber flowmaster
TCI streetfighter 700 r4
arizona speed and marine large tube runners, ported plenum, ported stock base plate 52mm throttle body
stock injectors at time of run
ZZ3 camshaft ,crane roller tip 1.5 rockers
MSD 6AL, blaster 2 coil ,modded mass air flow sensor ,ADS offroad chip
stock 3.27 rear
best et 13.59@103mph
steve
What kind of camshaft is good with a stock TPI. Made me think, I used LTx cams in the past but they bring your redline 6k+ So I imagine on tpi it would not be beneficial to use such a cam.
Perhaps this should be it's own topic though. I'm going to search a bit.
im not sure what mine will run. i just got my new motor in, still breaking it in. Suppose to take it to the track this sunday. I got a 357, 11.5:1 compression, better cam(not sure on specs) flat top forged pistons, balanced internals, 36# injectors, twin 58mm tb, ported plenum, better heads, 8.8 wires, accel high performance cap and rotor, msd 6al box, ram air hood(functional!), shift kit in the rebuilt 700r4, 2400 stall, electric water pump, aluminum pulleys, and i know those probably more, just cant think of anything else right now. Just got a 3.73 posi unit to slap in there next weekend. Any ideas of my times before and after the new rearend??? Thanks
There's also a difference between the MAF and the SD cars, the SD cars are usually a few tenths faster than the MAF cars for a few reasons.
No they aren't . Mine went 15.1 stock ( 305 5 speed w/ 3.08 lsd ) with 227'000km's on it. while another 1992 ( 305 5 speed w/ 3.23 lsd) ...and pulllies and headers and full catback , and tuneing . It went 14.7. The reason why the SD cars seem faster than the other modles ...is becasue they had more hp than the earlier ones. But in 1989 ... it was close in hp and tq. They perform the same.
regardless of MAF or SD .... they run about the same .... depending on driver. Now I have an untuned ZZ4 cam ( 353 cid)and all the stuff in my sig . I went 14.4 @65 mph . But I need to tune it and learn how to launch these finicky TPI cars. Couldn't get under a 2.2 60 ft.
regardless of MAF or SD .... they run about the same .... depending on driver. Now I have an untuned ZZ4 cam ( 353 cid)and all the stuff in my sig . I went 14.4 @65 mph . But I need to tune it and learn how to launch these finicky TPI cars. Couldn't get under a 2.2 60 ft.[/quote]
is that a typo are did you runn 14.4 at only 65 mph
mine did the same thing as far a traction. i just babied it off the line (with slight wheel hoop) bettered it to a 2.0 60' that led to a 14.2
No they aren't . Mine went 15.1 stock ( 305 5 speed w/ 3.08 lsd ) with 227'000km's on it. while another 1992 ( 305 5 speed w/ 3.23 lsd) ...and pulllies and headers and full catback , and tuneing . It went 14.7. The reason why the SD cars seem faster than the other modles ...is becasue they had more hp than the earlier ones. But in 1989 ... it was close in hp and tq. They perform the same.
regardless of MAF or SD .... they run about the same .... depending on driver. Now I have an untuned ZZ4 cam ( 353 cid)and all the stuff in my sig . I went 14.4 @65 mph . But I need to tune it and learn how to launch these finicky TPI cars. Couldn't get under a 2.2 60 ft.
I ran a 14.4 @ 95 as purchased with 135,000 miles. The only mods on the car were K&N's and some hack job cat-back with a 2 3/4" intermediate pipe. A Flowmaster Cat-back, TPIS Airfoil, Free mods and cool Fall air dropped mine down to 14.1 @ 98 with a 2.0 60ft.
My friend's 1990 Formula ran 14.3@95.4 last night with a 350, stock TPI, 230/230 cam, 305 heads, and 4.56 gears. I know...
I
__________________ '91 GTA L98
"What does matter is that the current GTA carries on the idea of the first Trans Am proudly and deservedly. It's still the most mature and
sophisticated ponycar. It still has character. It still has muscle. And it's still worthy of the name." -Car Craft, 1991
I recently picked up a 92Z28 with a TPI305/700R4 for my son. It has an LT1 rearend under it. I'm guessing 3:23 gears. 275/40/17's all the way around. It appears to have the free mods done, paper air filters, dumped exhaust with a flowmaster and no cat.
Best run at Kennedale(1/8 mile) last night was:
2.311
9.567
74.10 mph
just recently added headers and a little more timing but didnt get a chance to run it at the track... i've run a few low-mid 13 sec vehicles and stayed dead even with them... so im guessing with a good launch i should see high 13's... not bad for a now 203,000 KM 305 with free mods and headers
some suspension work could go a long ways, could be a decent differential?
423 RWHP is not too questionable. 02 firehawks run low 13's with 335 flywheel hp from the factory. I do not find it very doubtful. just my opinion.
i ran a 12.9 @ 108mph with a 1.9 60' earlier this year. i have a 350 tpi with edlebrock alu heade crane cams cam borla (no cat or smog) and 100 shot of no2
ONLY mods at the time...2.5" flowmaster catback, high flow cats, slp runners and 255s street tires on the rear + all free mods...untouched suspension.
This year ive done a boat load to my suspension and the T56 swap of course...no new times and i wont see the strip till next spring. Looking at doing heads/cam swap this winter and keeping TPI. Also gonna go either 3.42s or 3.73s in the rear.
The ported base, LS1 injectors, and ported air box got me my 13.5 today. I ran a 13.522 at 97.57mph, and my friend who's lighter than me ran a 13.546 at 100.39 so it hit a 13.5 and broke triple digits. I made 2 spray runs on a low bottle and got 12.2's both times once at 108 and once at 110. A pin hole in the upper radiator hose ended the day early but it still drove the 60 miles back home, I couldn't be more proud of her. I have a cell phone video of a few of the runs I'll post up when I get back to the cable to port them over.
He has no special system, this guys running a corvette with 4+3 tranny.
Same here...Ran my 85 4+3 Corvette coupe today for first time ever...
No burnout, just slipping the clutch to launch and smelling clutch all the way down track....and return road, LOL...
First pass: 14.20 @ 100.0 w/2.26 60 foot
Second, and best pass:
1/4:
13.93 @ 99.5 w/2.07 60 foot
1/8:
8.96 @ 78.7
Stock intake to oilpan 75,000 mile L98 w/12* base timing, de-screened maf, TB bypass, airfoil, K&N w/open lid, underdrive crank pulley, high flow catalytic converter and stock replacement mufflers...
its interesting to see how much relatively stock L98s differ in 1/4 times even if they have similar mods. ive seen some guys do 13.9s with STOCK cars, maybe exhaust, and ive seen guys with all kinds of bolt ons struggling to break 13.9s. i guess its all about tuning. im happy with my 13.9 sec L98, hopefully i will touch 13.4s with gears, stall converter, serious porting/tuning and ET drags....
Both sets of time slips are mine, the first set is off spray, the second set is on spray, the car did 13.5's off spray ,12.2's on spray. The car had 2 numbers because there were 2 people driving, 122 and 123 are both my car, the run that broke 100 was with the other driver who weighs about 80 pounds less than me. The LS1 injectors need a slight modification to get the TPI fuel rail clips to fit, I wrote a post about it a while back just do a search for LS1 injectors.
i did in quarter mile with my car was 0.5 seconds ;-) couple NASA rockets and rocket fuel easy to do but WARNING: these products may blow you to smitherines!!!
My 86 Trans Am
14.1@99mph with 2.3 60'
305LG4 converted to SD TPI with Crane Cams camsahft, stock 87 TPI heads, SLP Dual CAI, MSD 6A, MSD Blaster 3 Coil, shorty headers, 3" Pacesetter Catback, 3.42gears, T5 with Ripper Shifter and CF dual Friction clutch.
My 88 Formula
15.2@93mph with 2.1 60'
305TPI with HSR, stock manifolds, stock Y & I-Pipe, flowmaster muffler, T5 with Pro 5.0 shifter, 4.10 gears (these gears are too much for the T5), K&N cone filter.
I went 14.08 @96mph with extractors, exaust maf screens cut out and air pump delete in 350 88 GTA 82000mile Apparently it was pinging which could make sence as i just removed the stuffed air cleaner. Ran 14.2's the rest of the night
my new times!! changed they jaets in my nitrous system to 150 bhp and used it off the line to run an 11.9 @ 114 with a 1.8 60'. i did do a 1.7 60' the same day but only ran a 12.0! without the gas i ran a 13.6 @ 100. now i have new slp runners! watch this space......
1985 IROC 700R4 305 TPI with a few minor mods. Air foil, throttle body coolant bypass, descreened MAF. 3.42 open rear and spinning all through first gear ran a 15.26 and backed it up with a 15.27. 1985 has the good cams though. I want to get the 305 into the 14's without ever touching the internals. May have to get headers to do it.
I ran a 14.4 @ 95 as purchased with 135,000 miles. The only mods on the car were K&N's and some hack job cat-back with a 2 3/4" intermediate pipe. A Flowmaster Cat-back, TPIS Airfoil, Free mods and cool Fall air dropped mine down to 14.1 @ 98 with a 2.0 60ft. 
'91 GTA L98
