Swapping TPI system into my Nova street/strip car
09-04-2013, 07:35 AM
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Swapping TPI system into my Nova street/strip car
I am about to begin my carb to TPI conversion on my nova this weekend this weekend. I purchased the complete wiring harness and TPI system from a speed density 350 donor. The computer has a mail order tune from the previous owner who used trick flow heads and a .444 lift cam.
The goal for my Nova is to have improved street manners over the carb, better throttle response, maybe a few more mpg's on long trips, and would like mid 13's in the 1/4.
My 70 nova has 3:73 gears, TH350, and a 3000 stall converter in it now. I ran a best of 14.20 in the quarter with a temperamental 670 holley street avenger.
I will be adapting the TPI to my existing GenI 74' 350 block and heads. There is currently a .480 lift cam in the car that I know won't mesh well with the stock TPI intake for now but plan to upgrade to a high flow intake down the road. I purchased header collectors with provisions for the O2 sensors.
My questions to this board are what pit falls/frustrations do I have ahead of me. Any suggestions on cam size for a mild performance engine that see's occasional track time?
The goal for my Nova is to have improved street manners over the carb, better throttle response, maybe a few more mpg's on long trips, and would like mid 13's in the 1/4.
My 70 nova has 3:73 gears, TH350, and a 3000 stall converter in it now. I ran a best of 14.20 in the quarter with a temperamental 670 holley street avenger.
I will be adapting the TPI to my existing GenI 74' 350 block and heads. There is currently a .480 lift cam in the car that I know won't mesh well with the stock TPI intake for now but plan to upgrade to a high flow intake down the road. I purchased header collectors with provisions for the O2 sensors.
My questions to this board are what pit falls/frustrations do I have ahead of me. Any suggestions on cam size for a mild performance engine that see's occasional track time?
09-04-2013, 06:14 PM
#2
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Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Re: Swapping TPI system into my Nova street/strip car
What are the specs on the cam it was tuned for ?
The cam duration , LSA and valve overlap are what cause problems for computer controlled engines ; not the valve lift.
There are cams that are perfectly at home in a carb engine that are almost impossible to tune for on a EFI setup.
Same cam rules still apply ,
obviously more lift and duration to support a higher rev range than the TPI but the cam specs still limited by what the computer can control
This is why roller cams are so popular ; you can runs lots more valve lift without having the extra duration needed if you tried the same cam duration on a flat tappet cam like you have in the '74 engine
Last edited by vetteoz; 09-05-2013 at 07:56 AM.
09-05-2013, 06:12 AM
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Re: Swapping TPI system into my Nova street/strip car
The cam specs are: duration 230int./230exh.(@050), 110 degree lobe separation. I am prepared to change out the cam. I will be limited to flat tappet cam selections.
What are the spec on the cam you are using ?
What are the specs on the cam it was tuned for ?
The cam duration , LSA and valve overlap are what cause problems for computer controlled engines ; not the valve lift.
There are cams that are perfectly at home in a carb engine that are almost impossible to tune for on a EFI setup.
Same cam rules still apply ,
obviously more lift and duration to support a higher rev range than the TPI but the cam specs still limited by what the computer can control
This is why roller cams are so popular ; you can runs lots more valve lift without having the extra duration needed if you tried the same cam
duration on a flat tappet cam like you have in the '74 engine
What are the specs on the cam it was tuned for ?
The cam duration , LSA and valve overlap are what cause problems for computer controlled engines ; not the valve lift.
There are cams that are perfectly at home in a carb engine that are almost impossible to tune for on a EFI setup.
Same cam rules still apply ,
obviously more lift and duration to support a higher rev range than the TPI but the cam specs still limited by what the computer can control
This is why roller cams are so popular ; you can runs lots more valve lift without having the extra duration needed if you tried the same cam
duration on a flat tappet cam like you have in the '74 engine
09-05-2013, 06:18 AM
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Re: Swapping TPI system into my Nova street/strip car
The cam specs are: duration 230int./230exh., 110 degree lobe separation. I am prepared to change out the cam. I will be limited to flat tappet cam selections.
What are the spec on the cam you are using ?
What are the specs on the cam it was tuned for ?
The cam duration , LSA and valve overlap are what cause problems for computer controlled engines ; not the valve lift.
There are cams that are perfectly at home in a carb engine that are almost impossible to tune for on a EFI setup.
Same cam rules still apply ,
obviously more lift and duration to support a higher rev range than the TPI but the cam specs still limited by what the computer can control
This is why roller cams are so popular ; you can runs lots more valve lift without having the extra duration needed if you tried the same cam
duration on a flat tappet cam like you have in the '74 engine
What are the specs on the cam it was tuned for ?
The cam duration , LSA and valve overlap are what cause problems for computer controlled engines ; not the valve lift.
There are cams that are perfectly at home in a carb engine that are almost impossible to tune for on a EFI setup.
Same cam rules still apply ,
obviously more lift and duration to support a higher rev range than the TPI but the cam specs still limited by what the computer can control
This is why roller cams are so popular ; you can runs lots more valve lift without having the extra duration needed if you tried the same cam
duration on a flat tappet cam like you have in the '74 engine
09-05-2013, 08:10 AM
#5
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Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Re: Swapping TPI system into my Nova street/strip car
but the 110 LSA might be a problem.
Computers like > 112 ,110 needs a good tuner who knows his stuff
Check out the cam specs offered by this EFI vendor as a guide
http://www.tpis.com/parts/view/99
http://www.tpis.com/parts/view/84
http://www.tpis.com/parts/view/93
http://www.tpis.com/parts/view/100 ( the flat tappet cam version of above )
09-13-2013, 10:00 PM
#6
Supreme Member
Re: Swapping TPI system into my Nova street/strip car
As Vette said,, the 230/230 - 110 is a little tricky to tune,, especially with the Speed Density system,,, but doable. The overlap for the 230/230 - 110 is fractionally more than a 230/236-112 cam,, or about the same as a 232/236-112 cam.
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