cfm of cpi injection
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vortecfiero
New member
Re: cfm of cpi injection
when I first started planning my project I was going to stay with the CPI intake.
Rule of thumb math told me that the throttle body was the weakest link other
than the crappy popet style injector system... at 2.5 ID it will flow over 600cfm
in a turbo application which will support roughly 400hp. Of course the runners
could use a little tidying and opening up and the stock L35 heads will definatly
make that kind of power.
This manifold really wakes up the off boost midrange for those who have gone to a
larger AR ratio or larger later spooling set up.
Keep in mind the CPI was capable of 200 HP at 4500 rpm and 260 ft/lbs at 3500.
with the plenum tuning valve the torque curve was almost flat from 2000 to just
under 5000
Hope this helps
when I first started planning my project I was going to stay with the CPI intake.
Rule of thumb math told me that the throttle body was the weakest link other
than the crappy popet style injector system... at 2.5 ID it will flow over 600cfm
in a turbo application which will support roughly 400hp. Of course the runners
could use a little tidying and opening up and the stock L35 heads will definatly
make that kind of power.
This manifold really wakes up the off boost midrange for those who have gone to a
larger AR ratio or larger later spooling set up.
Keep in mind the CPI was capable of 200 HP at 4500 rpm and 260 ft/lbs at 3500.
with the plenum tuning valve the torque curve was almost flat from 2000 to just
under 5000
Hope this helps
scrape
New member
Re: cfm of cpi injection
thanks. i was guessing it was around 500 to 600 cfm stock. i plan on opening up the intake and gasket matching it and the heads and working the heads and possibly larger valves. i havent heard of anyone doing it, but i was also planning on polishing out the throat of the throttle body in front of the butterfly where it has that rough texture. i dont plan on boosting it although, i will probably go the bottle route. i want to keep it looking as stock as possible on the outside and under the hood.vortecfiero said:
vortecfiero
New member
Re: cfm of cpi injection
polishing did squat for me...
the biggest gain was 97 octane and advancing the timing 3 deg initial at the dist
and opening up the exhaust system. In a lighter car you can open the plenum
valve sooner and keep it open longer say 2600 up to 5000 rpm at WOT
I used a switch to open it manually.
my old setup
polishing did squat for me...
the biggest gain was 97 octane and advancing the timing 3 deg initial at the dist
and opening up the exhaust system. In a lighter car you can open the plenum
valve sooner and keep it open longer say 2600 up to 5000 rpm at WOT
I used a switch to open it manually.
my old setup
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scrape
New member
Re: cfm of cpi injection
i have been wanting to advance the timing, but im gonna have to get some stubby wrenches first. i cant hardly get my hand in between the firewall and engine to do it, and a socket with a wobbly extension wont get to it because of the angle it has to go. exhaust is pretty much open, but will be opened up more before long. im gonna cut it back to the muffler and put turndowns on it to get better flow plus i hate the way it sounds with the slash cut tips on it. i run 93 octane now and every chace i get to go to the drag strip i usually put a couple of gallons of 110 octane race fuel in the tank, if for no other reason i like the way it smells :rotf:.
well it will look cooler polished anywayvortecfiero said:
i have been wanting to advance the timing, but im gonna have to get some stubby wrenches first. i cant hardly get my hand in between the firewall and engine to do it, and a socket with a wobbly extension wont get to it because of the angle it has to go. exhaust is pretty much open, but will be opened up more before long. im gonna cut it back to the muffler and put turndowns on it to get better flow plus i hate the way it sounds with the slash cut tips on it. i run 93 octane now and every chace i get to go to the drag strip i usually put a couple of gallons of 110 octane race fuel in the tank, if for no other reason i like the way it smells :rotf:.