Ok guys, I need some input badly. Heres my issue. I have a fully built ls/vtec that was for daily driving but i crashed my car blah blah but anyway now its in a eg im making into a race car. The first dyno session it made 250whp@8200rpm 167wtq@6500rpm on 91 arco poopoo gas. Took it home, broke it in a little more crashed the car. my set up was as fallows prior to the accident:
b18b1 85 x 89
LA open deck sleeves
11.7:1 Arias pistons
Eagle H beam rods
Bensens knife edged and balanced crank
Type R oil pump
Everything blueprinted and balanced
b16a2 head
alaniz square port
supertech everything
Skunk2 Pro2 with Pro series cam gears
Blox port match manifold (not ported, just port matched)
BDL 70mm TB
Hytech big tube ITR header
RC 550cc injectors
BDL fuel rail

Now, i got a custom made B16 intake manifold that was port matched and ported all the way through with a giant round grenade launcher plenum. The hytech got smashed in the accident so i got a used DTR big tube side exit header. HERE is the dilemma, put q16 in it first pull....110whp.....126wtq....messes with it and final run was 257whp@8300rpm 176wtq@7400rpm WHY DID I ONLY GAIN 7whp?!?!?!??!?!?!??! it was tuned at Erick's Racing and he said top end something is making it drop. He said its the intake manifold but it also could be the header. what do you guys think? i need help here, i would like to see this motor hit peak power at 9000rpm. please please please let me know of anything you guys can think of to help me reach my goal.

P.S. the 250whp dyno session the dyno graph shows it just climbing and he stops because it was a fresh motor and didnt want to rape it just yet, 257whp dyno it just flattens out and falls after 8300rpm.

 

He could be right about the manifold but if you're tuning on two different dyno's you can't really compare numbers like that now can you... Maybe it was only 7hp on that dyno, could be 27hp on another.

It would be helpful if we could see your dyno graph along with air/fuel ratio logs as well.

 

All was done at Ericks Racing. i have the 250whp one which i compared with my 257whp one. The 250whp has a much nicer power curve that is nice and even on the way up but the 257whp one has less power then the first run but just like at 7800 or so it hits over 250whp. One dyno you can see the line much but the 257whp you can see it perfect.

 

 

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I spoke with someone today about it and hes saying that its most likely my header thats making me lose top end because i dont have the back pressure needed. the header was off a race motor that had higher compression. I was told as long as i have fuel to compensate for the big manifold it shouldnt be the problem. I'm so confused, can anyone please help me??!?!?!!

 

I haven't had a lot of time to look at everything but the guy that told you you don't have enough back pressure is crazy. Contact DTR and find out if that header is a good match for your setup and go from there. I'm thinking the intake manifold may have something to do with the results.

 

I found out that header used to be on a 2.0L 15.5:1 compression race motor. that manifold was on a 2.0L 11.5:1 daily driver that made 289whp so now im just lost completely. i have my old intake manifold back and im going with a bisi header and see if maybe that will bring my power back.

 

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Well if you only changed the intake manifold and header, I would start there...
Perhaps the new parts changed the way the engine breathes at a particular rpm?
Personally, Id start with a different style intake, maybe longer runners to regain your midrange...
Sounds like a nice setup.Now stop crashing your cars!

 

If you can, just change out the intake manifold first. I would guess on the intake manifold giving you a problem before the exhaust manifold. Then do the header. Look at that monster dip in torque at 6000rpm. Try to do the intake manifold header seperate so you have an idea of what is happening. Good luck.

 

Thanks guys for the input. i got my old blox manifold back which im going to put back on and a hytech replica im going to try and see if i can gain some power back. I'm going to do the intake first then have him dyno it then the header. i think if i put both on itll be better since the 250whp was a light tune and on shitty 91 and now im on q16. Thanks guys for the help.