tpivette89

just thought you fbody guys might be a little interested in what us Vette guys are doing with the old L98s these days. with minor bolt ons (and i do mean minor) i ran my best E/T last night at Cecil County dragway: 13.17 at 103.79mph w 1.77 60ft.

almost everything on the car is stock: the entire TPI intake, exhaust manifolds, heads, cam, gears, trans, air intake. the only mods i have are: K&N filter, airfoil, AFPR, Exotic Muscle front ypipe, Borla rear ypipe, S10 stall converter, drag radials, and some of the free mods. the car has no weight reduction, and its an auto with 3.07 gears.

my goal is to hit 12.99 with the stock TPI intake setup. no aftermarket base or runners. with the colder air coming, and some more tuning, i think its possible

MdFormula350

:hail: that is awesome, great work.

i would be in the high 13s with a 60 foot like that. time to get some drag radials for my old rims.

88 IROC BOB

Very nice. I've been thinking about going with the s10 convertor to help with the 60 ft's.

Bob

SLP IROC-Z

iTrader: (1)

nice! thats what L98s should be doin, and ur right those are definitly some minor mods!

TexasLT1

Thats awesome man, good work.

And to think I had to do an engine swap to hit low 13's oh well, maybe if I ever have to time to fix all the little things I can hit the mid 12's.

Mad-Mic

yeah i seen the timeslips! that is one mean stocker vette

mine hit a best of 14.57 sun after getting tuned up in the heat at 225 water temp with a 2.07 60' i picked up 4 mph in my last run of 14.62 @ 97 mph with a suck *** 2.29 60'

best time fri night but still at over 210 water temp was a 14.42.

i think if i can get her cooled down with good cool air and low 2.0 60' she'll hit a 13.8 or 13.9

all stock except maf descreened, k&n filter, cut air box, air foil, and no mufflers. stock rear Y and stock front Y pipes.

damn 2.59 gear is killing me

BTW it was nice meeting Tony and his g/f sunday for the race. i did make it to the semi's and damn red lighted. 2nd year in a row at the corvette shoot out i made the semi's.

one of my runs was 14.70 @ 85 mph dialed in on a 14.69. i think if i would of stayed in that run it would of been a 14.20 or so at around 98 mph.

damn tune up with ac delco rapid fire plugs, cap, rotor, 8 mm wires and accel super coil picked up over 4 mph sunday in the afternoon at 85 degrees compared to friday nights runs at 75 degrees!

tpivette89

Mad-Mic... my brothers 2.59 geared 91' Vette ran consistant 13.8s at 101mph with the follwing simple mods:

- K&N filter w cut lid
- ported plenum
- 160* stat
- AFPR

when youre installing the AFPR i gave you, port your plenum and install a lower temp stat while youre in there. you can also try bumping your timing a bit to see if that helps (run 93 octane or better though!). i would only bump your timing if youre running the lower temp stat though... 9+BTDC doesnt like 200+ degree coolant temps!

i stage with the coolant temps between 150 and 160. i also ice down my intake between runs. after those mods, and with a 2.0 60ft, you should have no problems hitting high 13s

HighHopes85

TPI, you mind posting your runs?

Something appears to be happening to my setup after the 1/8th. I left my datalogging power cable at home since I went spur of the moment. I am just curious.

BTW, I have 2.73's (85 had em) and I was spinning the tires about 20 feet off the line, launching at idle since the one run I brought it up to 2,000, I cut a 2.5X 60' time.

Any input from anyone would be great.

85 Vette, chip, exhaust, Crane 2040 cam.

http://expert.ics.purdue.edu/~msandine/RUN.htm

RBMZ28

Those are some amazing times!!!!!The best I've ever seen with very minor bolt ons was 13.8x out of a 85 vet. Doing the math has your h.p. rating at least 80 h.p. above fact. rating.......
I'm not reading your post as I type but is it the original motor??

tpivette89

yep, original L98 with 82k on the clock. intake has never been apart (just the plenum), and the valve covers have never been off. it also still has the factory exhaust manifolds
i dont have the slips right in front of me, but ill post them later if youre still interested. with a LTR setup, the first 1/8 mile is going to be strong, but due to the restrictive intake design the 2nd half of the quarter is much slower. this is probably especially true for your car. the factory intake is definately holding back the power you should be making with the exhaust and cam changes you have

Mad-Mic

man you need to lower your tire pressure! 20-28 psi at most. i'm having traction problems hardcore now after my tune up and minor mods i've done.

do you have an after market stall converter? please list your mods.

i stall out at 1600 rpm. thats all i can get and when i launch i spin thru 1st and sometimes into second. my best 60' time is 2.04. best ET at 45 degrees around 40% humidity with a water temp of 160 when staged was 14.24 at 98 mph and some change. she was bone stock. if i can get some good air and the motor cooled down to 160 degrees at stage i think i can pull a high 13 pretty easy with lower tire pressure. next track run i'm going with 24 psi instead of 28 psi and see what that does.

sounds like we are in the same boat. stock for stock the 85 had 10 less hp and 10 less lbs of torque compared to 87 thru 90 models. 91 had 250 hp 350 torque.

camarojoe

How much does a stock 89 vette weigh aprox.? That is an awesome time anyhow. Just shows you how quick a tpi engine can be when they hook.

tpivette89

roughly 3300lbs. slightly lighter that a similarly equipped fbody, but its still by no means a lightweight car

smithtc

iTrader: (5)

What are some of the "Free" mods you have done?
Fuel Pressure?
What about the suspension, shocks/struts, etc.?
Have you owned the car since new?

Those are the best times I have ever heard of for a car in the condition stated.

tpivette89

ive owned the car for about 5 years now... when i bought it it had 37k on the clock. i purchased it from some older guy (in his 60s) who had bought it new. he only drove the car on nice days. it was 100% original in every way when i picked it up.

absolutely NO suspention mods. in fact, the shocks are original all the way around. there are C4 Vettes running 1.6/1.5 60fts on the stock suspention. the IRS setup has been in Corvettes since 63, so Chevy has had plenty of time to get it right. this is nowhere near like either a Supras or Cobras IRS setup

as for my "free mods" ive got:

- cut filter lid
- descreeened MAF (fins are still in place)
- grinded down EGR walls in plenum
- timing bumped from 6* to 9*
- removed "frisbee"
- 160* stat
- gutted converter
- mufflers eliminated (straight pipes bolted in place)
- throttle body coolant bypass

poncho@home

How much do you think the plenum work helped? I seem to be stuck a 99 mph for the longest time. My car works really well. I am cutting 1.9x 60ft times on garbage street tires and running 13.8s all day long but I notice that my MAF rate plateaus at 4600-4700 rpm untill 5000...I wonder if the plenum can help me out a little.

HighHopes85

TPI-If you don't already have them in on your computer, don't worry about the times. I'll be making another trip to the track here in the next week (with my VSS fixed and timing set this time) and see where I can go from there. I'll also give lower tire pressures a whirl as mentioned. Thanks!

freestylzz

Ahhhhh...........

tpivette89

i didnt record the runs on video, and i dont have a scanner to put the actual slips on here, but i can post them numbers from them. hope this helps:

RUN #1
R/T : .067
60ft : 1.77
330 : 5.37
1/8 : 8.39
MPH : 81.05
1000 : 11.00
1/4 : 13.19
MPH : 103.78

RUN #2
R/T : -.043 (oops!)
60ft : 1.78
330 : 5.38
1/8 : 8.39
MPH : 81.24
1000 : 10.99
1/4: 13.17
MPH : 103.79

run #1 was made after about a 45 minute cooldown, and my coolant temps were in the 170* range. run #2 was after an hour cooldown and temps were in between 150 and 160*. all runs are made in "D" with about 20psi in the rear tires. i also ice the plenum while in the staging lanes.
not all that much... this mod falls into the "every little bit helps" catagory. so far i have only grinded down the EGR walls behind the throttle openings. i am going to take it one step further and siamese the plenum to runner openings on both the plenum and the upper runners for a bit more air flow

HighHopes85

Thanks! It did help.

tpivette89

went back to the track last night, but only got 1 run in due to cars that kept breaking. went 13.16 at 103.58mph with a 1.76 60ft. so the other runs werent a fluke, the car seems to be very consistant.

still trying to track down my missing mph... last year i was trapping 104+, but this year ive only run a best mph in the high 103s. maybe its the weather (the 104mph runs were in 40* temps in late Oct/early Nov). its just kinda dissapointing that i added a stall converter, gutted my cat, and eliminated my mufflers only to gain about a tenth AND i lost 1 mph.

Mad-Mic

sweet!

smithtc

iTrader: (5)

Have you tried backing your initial timing back down to track down that mph?

tpivette89

the timing was set to 9* when i was trapping 104mph last year. my best time for last season was a 13.20 at 104.22mph with a 1.78 60ft.

over the winter i had swapped my modified stock air intake for a TPIS unit, and added a 2500 stall converter. went to the track that March and ran a tenth and 2 mph slower than the past season (13.3 at 102mph). however, my 60fts improved from high 1.8s to high 1.7s.

i then swapped the TPIS intake for the modded stocker, as well as gutted my cat and removed the flowmaster catback in favor of a larger Borla rear ypipe and straight pipes. this dropped my E/T a tenth (back to 13.2s) but no mph change. this was also in the dead of summer.

then when the weather cooled a tad in early Sept, i removed my rapidfire plugs and put in a set of standard Delcos with cut back ground electrodes. this improved my E/T and mph to what it is currently. then i thought fuel delivery may be a problem, so i replaced the fuel pump and changed the filter. no changes from that.

ive done just about everything i can think of. the only solution i am seeing now is that my 104mph runs were in late Oct when the weather was in the 40s and humidity was low. ill just have to wait and see if i can run better #s when it gets colder

poncho@home

Their might be more slippage in the new torque convertor on the top end accounting for your drop in MPH.

SLP_GTA

iTrader: (1)

do you have the stock #22 injectors? what is your fuel pressure settings vacuum unhooked.

Man I have Mods O'penty and have only run best 60 2.16
14.42 @ 97.8 with a full tank. yesterday I check my timming
6BTDC and checked the autoXray, no spark knock and isnt back off timming, the total timing was between 32-34 @ 2500-3000.

Does it seem like I can bump up my timming 3 or 4 degrees to get a total timming of 38. and Also would it make much of a performance diff.

tpivette89

stock 22# injectors, stock fuel pump, and i run 48psi w the vac hose disconnected

timing definatly helps for TPI cars. heres a little story why:

last year when i installed a front ypipe i went to the track and noticed no change in E/T or mph. i was pissed. so i checked everything... what it turned out to be was my base timing had slipped to 3*BTDC. i guess i didnt tighten the hold down bolt all the way last time i had adjusted it, and over the course of a few weeks it allowed the dist to move. sooo i bumped my timing up from 3* to 9* and went from a 13.40 at 102.78mph to a whopping 13.20 at 104.22mph!!

however, i wouldnt run too much timing unless you are running premium gas (93 octane or better), and have some way of keeping your coolant temps low. advanced timing + low octane and high coolant temps = detonation!

Mad-Mic

when i bumped my timing up i gained 6 tenths. my best run this year with all the mods in my sig besides the hi-flow cat and front Y pipe was a 14.47 with a 2.07 60'. best time ever was totally stock and was a 14.24 with a 2.04 60'.

bumped the timing from 6* BTDC to around 10-12* BTDC and went a 13.95 with a 3 mph gain. this year. best before this was dead stock and ran 98 mph.

so overall i picked up3 tenths and 1 mph. hopefully with the front Y pipe and hi-flow cat she'll run a low 13.7 or high 13.6 on street tires with a 1600 stall and a 2.59 rear gear. i only run 93 or 94 octane. if the station don't have atleast 93 (which is very rare) i'll run 92 octane but never less than that, never did never will. in my 82 Z/28 i can't run less than high octane or it'll ping bang and stay running after i turn the car off with alot of timing in that car where she barely starts but once she does you definetly notice it.

BTW vette's fuel systems are good for over 400 hp. anything over 450 hp you need a higher volume pump atleast.