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comparison of a turbo sohc vs turbo dohc

2K views 4 replies 5 participants last post by  NAPALM 
#1 ·
so check this out guys
me and ben have the same size injectors (rc 1000cc/min), same base fuel pressure.

he's got the HTA35r, ive got the gt35r similar turbos, hta is supposed to make a bit more power at higher boost.

anyway, at 20psi he's using 65% of injectors @ 6700~rpm (dunno why he';s not revving it higher), and at 18-19 psi with the stock sohc head, i was only using 54%, thats 540cc of fuel vs 650cc of fuel.. major diff!

shows you how efficient the evo head really is :]
 
#2 ·
Ahh, though you had your DOHC up and running!

Nice compariosn though. Assume you guys are running the same AFRs right? Can you log airflow as well the EMS?
 
#5 ·
Sup yos, heres the log that zee was looking at.
http://webpages.charter.net/bosorio/3G/tmep/boost.JPG

If I remember correctly zee you had the RPW stage 3 camshaft when you ran 18-19psi?

Also a couple other things;
My injectors came with the flow datasheet from RC and all were within 998-1005cc.

I was running 70-72% a couple of weeks ago when I had the timing cranked up real high (15-20° advance with 20psi). But it makes more power the way it is now, also uses less fuel, spools the turbo quicker, and theres no knock.

Not when you're running a MAP based cal.

is he using stock stock cam?

That can make a big difference. I'll definately post how mine goes with a SOHC, and a RPW cam when I get mine up and running.

I would personally like to see some dyno's sometime. the comparison only makes a perfect comparison if you two both had the exact same A/F ratio. Some people like to run leaner with less timing, and others like rich with more timing. It could be a big difference if one of you two were running like 11.0 and the other 11.8.

I think the best comparison would be to do a flow test on the two different heads. Intake and exhaust. I am certain the DOHC would flow more due to the larger intake ports, but it would be a good comparison. I was actually skeptical until I saw a comparison of the two intake gaskets, and the EVO intake dwarfes our SOHC one. I'm not so sure the exhaust will flow any different though, since we have the same exhaust gaskets....
Yes stock evo cams (100% stock evo head).
I run 11.2:1 AFR. I believe zee runs about the same.
 
#3 ·
is he using stock stock cam?

That can make a big difference. I'll definately post how mine goes with a SOHC, and a RPW cam when I get mine up and running.

I would personally like to see some dyno's sometime. the comparison only makes a perfect comparison if you two both had the exact same A/F ratio. Some people like to run leaner with less timing, and others like rich with more timing. It could be a big difference if one of you two were running like 11.0 and the other 11.8.

I think the best comparison would be to do a flow test on the two different heads. Intake and exhaust. I am certain the DOHC would flow more due to the larger intake ports, but it would be a good comparison. I was actually skeptical until I saw a comparison of the two intake gaskets, and the EVO intake dwarfes our SOHC one. I'm not so sure the exhaust will flow any different though, since we have the same exhaust gaskets....
 
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