93egSLEEPER

IMO with the Victor X and it's large plenum volume I think its beneficial to have better velocity coming in the plenum vs. volume, which goes in line with what you are saying. I have shown with my dyno's a smaller TB on that intake manifold will hold it's own. It is almost like the reverse effect of the ultra street and big TB setup...at least in my head lol. I am only running a Omnipower 70mm and carry power to 9200. The real test would be to throw a 74mm on it and see what happens though.

PyroProblem

Or even a 68mm throttle body.
Yeah, I think people underestimate what kind of air can move through a 70mm opening. IDK when 70mm becomes a restriction, but if going to a 68mm TB helps in power, then it definitely isn't being maxed out. So your losing velocity in exchange for more flow that you don't need yet. Seeing some stuff on here makes me wanna test out some smaller TBs when my time comes. Street driving with a big TB is kinda a PITA to me as well, but im probably just getting old lol.

93egSLEEPER

LOL. I need to re-measure my TB. I think the omni 70mm might be a 70mm opening that tapers to 68...can't remember.

Wilka

iTrader: (1)

Bottom line is the car still made 238 whp with only thing being changed is ati pulley, and header and I moved backwards..

ChrisCoupe1

I thought you said injectors from dsm 440's to the 410rdxs ? Also as mentioned before even if injector duty cycle wasn't being stressed the higher fuel flow from upping the fpr psi could possibly help spray pattern

Wilka

iTrader: (1)

When I bought motor I put rdx injectors in, the throttle body and plm header and made 239, then put on radials, an ati pulley and hytech and came back for a clean up tune and made the 225

Wilka

iTrader: (1)

I figure a straight 2 liter with the best flowing factory head and second or third biggest cam skunk2 has to offer off the shelf and the fact I'm reving it to 9/9200 its going to want some air.

As to everyone else who suggest a fuel pressure issue with injectors, I'm at factory fuel pressure recommendations for b series, I still made 239 with the rdx injectors as they sit now, but could it be switching to the hytech header changed scavenging properties of the cylinder and they just aren't spraying optimally for it to all function as I'm ideally imagining it should? Should I change fp to the 55-60 psi and watch the wideband to see what its going to do?

PyroProblem

There was a guy named Greg/cheetah who used to work with Larry from Endyn building race engines. 1 engine they we're working on was a 92 by 84.5 b series. Larry kept telling Greg to lose the larger TB and go with a 68 (or something similar). Finally Greg did just that and picked up power. This was on a near 300 BHP b series engine.

Food for thought

93egSLEEPER

The thing is, going from a 68mm to 74mm TB may show a 4-5whp gain for peak power, but you have to look at the whole curve, not just peak. From what I have noticed, the larger TB might add a little peak, but you will lose more on the mid and upper mid half than you gain on top. If all you care about is a peak number then yea a larger TB may help you get that, but you could also suffer everywhere else aside from the last 300rpm of the powerband. I personally would rather miss a few up top and gains over the entire powerband.

Just throwing this out there. Was the dyno re-calibrated at any point? I wish we had more than a dyno number to work from. They are not the end all. Track numbers and the such are indicators as well.

$hawNPeeZyy

You are on factory fuel pressure recommendations for a b series engine, but you are not using b series injectors. The factory base fuel pressure on an Acura RDX is 55 psi.

Wilka

iTrader: (1)

I ran the car untuned or on previous tune before it was cleaned up and corrected to 228whp on this header with 219whp and went 13.0 with 1.9 60ft and trapping 105ish

Wilka

iTrader: (1)

Yeah, this light bulb just went off in my head when you or someone else mentioned it. I feel kind of dumb for not thinking of it on the dyno or that my tuner didn't think of it.

Wilka

iTrader: (1)

Tuner doesnt seem to think that being from 39 to 60 psi would do much for an explanation of my peak numbers or dip between 5600-7200ish

93egSLEEPER

Fuel atomization will effect the whole tune. Correct me if I'm wrong.

ChrisCoupe1

Yeah he may not have seen the need considering the power you were making 410cc/min would run a "safe" duty cycle in the 220whp range . But for your power goal and the setup you have the numbers point to wanting more fuel delivery to make 250whp at a reasonable duty cycle. I consider reasonable as no more then 85% so the injectors stay happy....the RDX's bumped to 55 ish PSi is around 500cc which should be good for 80% duty cycle at the 250 whp mark. So maybe the setup as it sits won't get to that but there's the rough numbers on what the fuel aspect.

Wilka

iTrader: (1)

Still don't understand how I made 239 whp on a plm, then put previous owners header on when the motor made 245whp. I'm moving backwards it seems.

$hawNPeeZyy

Trial and error is the name of the game, its all a learning experience my friend. Do you still have the previous owner's header? If so, try throwing it back on, throw the 68mm TB back on, turn the RDX injectors up to at least 55 psi and see what it does...

Wilka

iTrader: (1)

Yes, that's what I'm saying, I'm only getting 228 out of the previous owners header when I know for a fact it works.

ChrisCoupe1

Just reading back through this and see you say that your running a 3inch Axel back...so just curious but what's sitting between your header and the Axel back? If it's stock or even 2.5 inch mid pipe you could be loosing power there.

Wilka

iTrader: (1)

The header connects straight to 3 inch aluminum custom exhaust.

ChrisCoupe1

Very nice, well that clears that up.... So give any thought to when you'll attempt a retune run on the dyno?

Wilka

iTrader: (1)

Waiting on my federal car part stimulus package lol, and cutting some weight from the car, if we can get 250 or more out of it, then I'm aiming for 12 flat even though I know the car has 11's in it.

Wilka

iTrader: (1)

Anyone recommend an intake manifold other than my ported runner and throttle body matched gen 1 victor x?

93egSLEEPER

Only IM worth giving a shot over the Vic X IMO would be an ultra street w/ some spacers. Ported if possible. That's my opinion though.

PSI GUY

iTrader: (2)

I spent a lot of money to go to the ultra race ported with a 90mm throttle body and barely topped the ported victorx. Use your money elsewhere.