Budget TPI 350 build
10-18-2018, 06:54 PM
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Car: 1986 IROC-Z
Engine: 5.7 TPI, 113 heads, Comp Cam
Transmission: 700R4, 2500 stall
Axle/Gears: 3.42 Posi
Budget TPI 350 build
I put this together over 4 years ago, only driven about 500mi so far. Wanted to get some feedback on the setup and maybe what could be better. I datalogged a few weeks ago and calculated HP based on MAF, then Torque from there. Only ran to 4200rpm so I’m sure it will make a few more to 4800-5000. 235hp/300tq
Car is an ‘86 IROC LB9/Auto originally
Short block- stock rebuilt 1992 L98
Heads-ZZ4, mild port and bowl blend by me to clean up casting and smooth out the turns. Matched to 1204 intake gasket, new LT4 spring kit
Cam- Comp 08-412-8, 212/218, 110lsa, .487/.495 lift, stock rockers and lifters, ZZ4 timing set and pushrods
Stock base manifold, ported by High Flow FI, matched to 1204 and 1 3/4” inlets (MrGasket 146), stock runners, matched to gaskets, plenum ported and cleaned up inside, Stock TB, rebuilt, 52mm
SLP headers, custom Y, no cats, Flowmaster 3” single,
19lb injectors, Racetronix/Waldron 255, 3 wire O2, tuned by PCMofNC, AEM wideband
Emissions delete, Serpentine conversion, March pulleys
700r4, 2400 stall, Vette servo, hd rebuild, 3:42 Posi rear.
I have a set of AS&M runner to put on once they are cleaned up.
It runs great and feels good off the line and higher rpm. Kind of weak in the middle. May need timing ramped in sooner. Thought about changing the rockers, might help a little. What do you guys think? Should I expect more out of it?
Car is an ‘86 IROC LB9/Auto originally
Short block- stock rebuilt 1992 L98
Heads-ZZ4, mild port and bowl blend by me to clean up casting and smooth out the turns. Matched to 1204 intake gasket, new LT4 spring kit
Cam- Comp 08-412-8, 212/218, 110lsa, .487/.495 lift, stock rockers and lifters, ZZ4 timing set and pushrods
Stock base manifold, ported by High Flow FI, matched to 1204 and 1 3/4” inlets (MrGasket 146), stock runners, matched to gaskets, plenum ported and cleaned up inside, Stock TB, rebuilt, 52mm
SLP headers, custom Y, no cats, Flowmaster 3” single,
19lb injectors, Racetronix/Waldron 255, 3 wire O2, tuned by PCMofNC, AEM wideband
Emissions delete, Serpentine conversion, March pulleys
700r4, 2400 stall, Vette servo, hd rebuild, 3:42 Posi rear.
I have a set of AS&M runner to put on once they are cleaned up.
It runs great and feels good off the line and higher rpm. Kind of weak in the middle. May need timing ramped in sooner. Thought about changing the rockers, might help a little. What do you guys think? Should I expect more out of it?
10-18-2018, 07:16 PM
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Car: 1990 G92 IROC Z Miniram
Engine: 388cu 6.4 Liters
Transmission: G-Force T5
Axle/Gears: 3.73 Gears
Re: Budget TPI 350 build
I put this together over 4 years ago, only driven about 500mi so far. Wanted to get some feedback on the setup and maybe what could be better. I datalogged a few weeks ago and calculated HP based on MAF, then Torque from there. Only ran to 4200rpm so I’m sure it will make a few more to 4800-5000. 235hp/300tq
Car is an ‘86 IROC LB9/Auto originally
Short block- stock rebuilt 1992 L98
Heads-ZZ4, mild port and bowl blend by me to clean up casting and smooth out the turns. Matched to 1204 intake gasket, new LT4 spring kit
Cam- Comp 08-412-8, 212/218, 110lsa, .487/.495 lift, stock rockers and lifters, ZZ4 timing set and pushrods
Stock base manifold, ported by High Flow FI, matched to 1204 and 1 3/4” inlets (MrGasket 146), stock runners, matched to gaskets, plenum ported and cleaned up inside, Stock TB, rebuilt, 52mm
SLP headers, custom Y, no cats, Flowmaster 3” single,
19lb injectors, Racetronix/Waldron 255, 3 wire O2, tuned by PCMofNC, AEM wideband
Emissions delete, Serpentine conversion, March pulleys
700r4, 2400 stall, Vette servo, hd rebuild, 3:42 Posi rear.
I have a set of AS&M runner to put on once they are cleaned up.
It runs great and feels good off the line and higher rpm. Kind of weak in the middle. May need timing ramped in sooner. Thought about changing the rockers, might help a little. What do you guys think? Should I expect more out of it?
Car is an ‘86 IROC LB9/Auto originally
Short block- stock rebuilt 1992 L98
Heads-ZZ4, mild port and bowl blend by me to clean up casting and smooth out the turns. Matched to 1204 intake gasket, new LT4 spring kit
Cam- Comp 08-412-8, 212/218, 110lsa, .487/.495 lift, stock rockers and lifters, ZZ4 timing set and pushrods
Stock base manifold, ported by High Flow FI, matched to 1204 and 1 3/4” inlets (MrGasket 146), stock runners, matched to gaskets, plenum ported and cleaned up inside, Stock TB, rebuilt, 52mm
SLP headers, custom Y, no cats, Flowmaster 3” single,
19lb injectors, Racetronix/Waldron 255, 3 wire O2, tuned by PCMofNC, AEM wideband
Emissions delete, Serpentine conversion, March pulleys
700r4, 2400 stall, Vette servo, hd rebuild, 3:42 Posi rear.
I have a set of AS&M runner to put on once they are cleaned up.
It runs great and feels good off the line and higher rpm. Kind of weak in the middle. May need timing ramped in sooner. Thought about changing the rockers, might help a little. What do you guys think? Should I expect more out of it?
Last edited by VincentZ28; 10-18-2018 at 07:20 PM.
10-18-2018, 07:27 PM
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Car: 1986 IROC-Z
Engine: 5.7 TPI, 113 heads, Comp Cam
Transmission: 700R4, 2500 stall
Axle/Gears: 3.42 Posi
Re: Budget TPI 350 build
A/F is very solid 14.6/7 idle and cruise. Low 12’s under full throttle. The tune has been adjusted a few times based on datalogs. I know the injectors are not ideal but my duty cycle is well below maxed out. I don’t think it’s lean at all. And I only see a few knock counts above 3000rpm at WOT.
10-18-2018, 07:31 PM
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Car: 1986 IROC-Z
Engine: 5.7 TPI, 113 heads, Comp Cam
Transmission: 700R4, 2500 stall
Axle/Gears: 3.42 Posi
Re: Budget TPI 350 build
The cam was recommended by Comp but may be the culprit. A wider LSA would have helped the intake waves of the tpi from what I have read. In their cam Dyno software it really looked good but I did question the 110 lsa.
10-18-2018, 08:55 PM
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10-19-2018, 02:23 AM
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Car: 1986 IROC-Z
Engine: 5.7 TPI, 113 heads, Comp Cam
Transmission: 700R4, 2500 stall
Axle/Gears: 3.42 Posi
Re: Budget TPI 350 build
ASE Master & L1 Advance certified for 20 years. Yes, I know how to set timing.
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02-11-2021, 02:27 PM
#9
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Car: 1986 IROC-Z
Engine: 5.7 TPI, 113 heads, Comp Cam
Transmission: 700R4, 2500 stall
Axle/Gears: 3.42 Posi
Re: Budget TPI 350 build
Just an update for anyone who stumbles across this in the future. I changed some parts and the engine runs much better now, lots more power. I was hoping to have dyno or track #s but not yet.
First was changing to AS&M large tube runners, and porting the plenum to match. The base was almost a perfect match to them already. Also replaced the injectors with 22lb Bosch III’s from Southbay. Bought a chip burner and a few chips to start tuning myself. Used the 6E wideband hac bin to datalog, transferred all data from the custom chip to the new bin, changed the injector data for the new Bosch’s and re-baselined the iac, fuel pressure and spark. A few datalogs and MAF table changes later, this thing runs great! Way more torque and pulling through higher rpm. Still working out small details when time alows again. Big thanks to all the tech, tuning and injector info on this forum!
First was changing to AS&M large tube runners, and porting the plenum to match. The base was almost a perfect match to them already. Also replaced the injectors with 22lb Bosch III’s from Southbay. Bought a chip burner and a few chips to start tuning myself. Used the 6E wideband hac bin to datalog, transferred all data from the custom chip to the new bin, changed the injector data for the new Bosch’s and re-baselined the iac, fuel pressure and spark. A few datalogs and MAF table changes later, this thing runs great! Way more torque and pulling through higher rpm. Still working out small details when time alows again. Big thanks to all the tech, tuning and injector info on this forum!
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