Ran the car today
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Car: 1989 Iroc Z L98
Ran the car today
Hey guys,
So I ran the car today, I only got 2 good passes as 2 consecutive cars oiled the entire track and I wound up leaving.
My car is a close to stock 1989 Iroc Z with:
350TPI
9 bolt with 2.73 gears
3600 lbs w/ driver
Magnaflow 3" muffler
No cat
K&N filters
Radial Tires on stock 16" wheels
My first pass was as follows:
60' 2.275
ET: 14.93
MPH: 93.19
Second pass:
60' 2.201
ET: 14.87
MPH: 92.91
I really didn't have much trouble with traction rolling into the throttle. I am wanting to get this thing down to the high 13's with bolt-ons. What should my next mod(s) be? I am pretty much undecided between 3.42's or headers...
So I ran the car today, I only got 2 good passes as 2 consecutive cars oiled the entire track and I wound up leaving.
My car is a close to stock 1989 Iroc Z with:
350TPI
9 bolt with 2.73 gears
3600 lbs w/ driver
Magnaflow 3" muffler
No cat
K&N filters
Radial Tires on stock 16" wheels
My first pass was as follows:
60' 2.275
ET: 14.93
MPH: 93.19
Second pass:
60' 2.201
ET: 14.87
MPH: 92.91
I really didn't have much trouble with traction rolling into the throttle. I am wanting to get this thing down to the high 13's with bolt-ons. What should my next mod(s) be? I am pretty much undecided between 3.42's or headers...
#2
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Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Ran the car today
Gears. Those 2.73 gears are really hurting performance. Along with the gears, get some sticky tires.
#3
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Car: 1989 Iroc Z L98
Re: Ran the car today
Thanks!
#4
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Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Ran the car today
I had a hopped up 383 through a TH350 and 3.27 gears and ran very high 11's. The gearing was wrong but I still ran good times with only 3.27 gears and 26" tall slicks.
Changed to a 10 bolt, 4.10 gears and 28" tall tires and got into the low to mid 11's.
3.70 may be a little too much with a 700R4. The starting ratio would be very low. On the highway, even with the overdrive, you will notice a loss of fuel mileage but stoplight to stoplight driving will be fun. The TPI doesn't like high rpms so gearing for higher rpms won't gain much performance.
Changed to a 10 bolt, 4.10 gears and 28" tall tires and got into the low to mid 11's.
3.70 may be a little too much with a 700R4. The starting ratio would be very low. On the highway, even with the overdrive, you will notice a loss of fuel mileage but stoplight to stoplight driving will be fun. The TPI doesn't like high rpms so gearing for higher rpms won't gain much performance.
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Car: '02 Z06
Engine: L33 5.7
Transmission: T56
Axle/Gears: Stock IRS
Re: Ran the car today
Can't go wrong with gears or headers. Whatever you can get a good deal on first is what I would do. I know headers are possibly the single best mod you can do to the engine for instant 1/4 mile gains.
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Car: 1989 Iroc Z L98
Re: Ran the car today
That's the kind of answer I was looking for . So you think 3.70's won't be too steep for a TPI motor? I don't care about RPMs on the freeway as much as 1/4 mile performance.
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#8
Re: Ran the car today
I'd do drag radials and a 2800 stall converter...then headers and a mild tune. Try giving it 2-3 deg more base timing or get the software/chip burner and really do some good work.
You'll gain MUCH more with a converter than any of the other mods at this time. 2.73's arent great but with converter you'll have 13's capable car. I went 13.89 at 97 with 2800 stall and 2.77 gears on street tires. Eventually added 3.42's and slicks and went 13.63 so not much more gained.
Your 60's should come down from 2.2's to 1.8's without much effort and likely hit high 1.7's
You'll gain MUCH more with a converter than any of the other mods at this time. 2.73's arent great but with converter you'll have 13's capable car. I went 13.89 at 97 with 2800 stall and 2.77 gears on street tires. Eventually added 3.42's and slicks and went 13.63 so not much more gained.
Your 60's should come down from 2.2's to 1.8's without much effort and likely hit high 1.7's
#10
Re: Ran the car today
Dont forget with headers/tune, you may start to approach 96-98mph plus! I know my car with full exhaust was in the 96-97 range but changed to 3.27 gears and it went 99-100mph in good air. Back to 3.42's and slicks it went back down to 97mph...not sure why
3.42's are best IMO but 3.70's/3.73's can work ok. They work better with siamesed runners or aftermarket intakes
3.42's are best IMO but 3.70's/3.73's can work ok. They work better with siamesed runners or aftermarket intakes
#11
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Car: 1989 Iroc Z L98
Re: Ran the car today
Thanks for all the replies guys, sounds like my next mod will be a torque converter! Any recommendations on a budget converter? Anything I should do since my car has 90k miles on it as far as the transmission goes if I am upgrading the converter?
#12
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Car: '02 Z06
Engine: L33 5.7
Transmission: T56
Axle/Gears: Stock IRS
Re: Ran the car today
I've learned that budget converters are no good. Get a real good one and never look back. Vigilante and Edge come to mind.
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Car: 1989 Iroc Z L98
Re: Ran the car today
I hear you, I had a Hughes in my TH350 and loved it. I have reservations about putting a $500-$1000 converter in a transmission with 90k miles on it though... Thoughts?
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Car: 1987 Pontiac Trans Am
Engine: 350 Vortec
Transmission: 700R4
Axle/Gears: 3.42
Re: Ran the car today
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Car: 87 IROC
Engine: LB9
Transmission: T5
Axle/Gears: 3.70 9 bolt
Re: Ran the car today
Do you have a 9 bolt or do you have 2.73s, because those don't go together. Definitely get better gears, 3.70 would be 9 bolt and 3.73 would be 10 bolt.
Also don't forget that you likely need a different carrier for higher gears since your stock set is the highway gears.
Also don't forget that you likely need a different carrier for higher gears since your stock set is the highway gears.
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Car: 1989 Iroc Z L98
Re: Ran the car today
Yeah the carrier is really what is holding me back, 9bolt.com sells them for like $400, so it is something I will have to score used from someone on here or ebay. There are zero on ebay right now too. Oh well looks like I am going converter first now.
#18
Re: Ran the car today
If it was a 2.73 10 bolt you can get 3.73's designed for 2 series carrier and run those. Thats what I did on my 99 TA.
But being an 89 iroc its likely a 2.77 9 bolt. Thats what I had. Gears are harder to find for those and carriers even harder. I thought the company in australia was recently re-started that imported 9 bolt stuff since it was still used over there. not sure tho
But being an 89 iroc its likely a 2.77 9 bolt. Thats what I had. Gears are harder to find for those and carriers even harder. I thought the company in australia was recently re-started that imported 9 bolt stuff since it was still used over there. not sure tho
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