305 TPI potential on "stock" long block
Thread Starter
Member
Joined: Apr 2001
Posts: 244
Likes: 0
From: Boyertown, PA
Car: 84 Z28
Engine: 91 L98 long block with Pro-jection
Transmission: T5
Axle/Gears: 91 10bolt w/ 3.42s and T2R
305 TPI potential on "stock" long block
I'm considering building a 305 TPI car at some point in the future to run in SCCA's ITR class. My question is about the power potential given the following parameters.
Must be a 305 from 87-92, and I must use the entire unit (can't mix and match heads/blocks/cams/etc.). I'm assuming 90-92 LB9 is the best starting point.
Can go up to .040" over, and use any pistons that are *stock configuration* and no lighter than stock.
Stock rods.
Stock crank.
All can be balanced and blueprinted.
Stock cam, stock cam timing.
Stock heads, with all stock pieces (valves, springs, rockers, etc.), can be portmatched 1" in. Can mill heads to "service limit", max gain of .5 for compression.
Stock intake and TB, can be portmatched at the head interface ONLY (also only 1"). Can lose the water to the TB.
Exhaust is essentially unlimited once you leave the head.
EGR/Air pump can be removed.
ECM is unlimited.
Fuel pump and regulator are free (stock injectors).
Can be MAP or MAF, but if MAF I have to run the stock unit.
Anything (other than MAF) in front of the TB is open, but no cowl/ram air.
Any ignition.
Any wet-sump oil system.
Stock flywheel.
Underdrive pulleys OK.
Given the above, run to the absolute limit, my gut tells me 225 RWHP (must use a WCT5) at most.
Thoughts?
Anyone have any dyno results of a truly stock LB9? Any LB9 builds like this?
Any other thoughts?
Must be a 305 from 87-92, and I must use the entire unit (can't mix and match heads/blocks/cams/etc.). I'm assuming 90-92 LB9 is the best starting point.
Can go up to .040" over, and use any pistons that are *stock configuration* and no lighter than stock.
Stock rods.
Stock crank.
All can be balanced and blueprinted.
Stock cam, stock cam timing.
Stock heads, with all stock pieces (valves, springs, rockers, etc.), can be portmatched 1" in. Can mill heads to "service limit", max gain of .5 for compression.
Stock intake and TB, can be portmatched at the head interface ONLY (also only 1"). Can lose the water to the TB.
Exhaust is essentially unlimited once you leave the head.
EGR/Air pump can be removed.
ECM is unlimited.
Fuel pump and regulator are free (stock injectors).
Can be MAP or MAF, but if MAF I have to run the stock unit.
Anything (other than MAF) in front of the TB is open, but no cowl/ram air.
Any ignition.
Any wet-sump oil system.
Stock flywheel.
Underdrive pulleys OK.
Given the above, run to the absolute limit, my gut tells me 225 RWHP (must use a WCT5) at most.
Thoughts?
Anyone have any dyno results of a truly stock LB9? Any LB9 builds like this?
Any other thoughts?
Joined: Aug 2006
Posts: 1,376
Likes: 7
From: Northern California - Bay Area
Car: 1988 IROC-Z
Engine: L98 - full intake & exhaust boltons
Transmission: Bowtie 700r4, 2400 rpm stall
Axle/Gears: Borg-Warner 9bolt, 3.45 gears, posi
Re: 305 TPI potential on "stock" long block
https://www.thirdgen.org/forums/memb...-91-z28-2.html
Check out this thread. This member has a '91 Z28 LB9/5-speed/G92 car. His car has the same cam that came in the L98's. Most of the car is stock with the exception of full exhaust from the headers back. I think he said his dyno results were 215hp at the rear wheels. Check the thread to be sure.
If you plan to do a stock 305 TPI and use it for your race build, make sure you use a cam that has the same specs as the L98. The 5-speed LB9 cars that have the G92 option should have the bigger cam.
The '91-'92 LB9/5-speed/G92 cars were rated at 230hp and 300 pound feet of torque at the flywheel.
For the '91-'92 model years the L98 was rated at 245hp and 345 pound feed of torque at the flywheel
Check out this thread. This member has a '91 Z28 LB9/5-speed/G92 car. His car has the same cam that came in the L98's. Most of the car is stock with the exception of full exhaust from the headers back. I think he said his dyno results were 215hp at the rear wheels. Check the thread to be sure.
If you plan to do a stock 305 TPI and use it for your race build, make sure you use a cam that has the same specs as the L98. The 5-speed LB9 cars that have the G92 option should have the bigger cam.
The '91-'92 LB9/5-speed/G92 cars were rated at 230hp and 300 pound feet of torque at the flywheel.
For the '91-'92 model years the L98 was rated at 245hp and 345 pound feed of torque at the flywheel
Thread
Thread Starter
Forum
Replies
Last Post
Sanjay
Engine/Drivetrain/Suspension Parts for Sale
1
Aug 12, 2015 03:41 PM
