rx slim

I posted a problem with boost creep a while back, and was seriously thinking about porting my wastegate. JyRO responed that he was designing some restrictor plates for placement in the exhaust to help limit boost creep. I took him up on his offer and he fabricated three different sized plates and shipped them to me for a reasonable price. The middle plate (forgot what size port it had) fixed my problem and now my boost controller can dial-in my desired boose like a champ. Just wanted to give him his props, and if anybody has similar problems (I don't want to put words in his mouth), maybe he will be willing to help you also. He's a freakin genius.

KaiFD3S

iTrader: (37)

congrats, I wonder how that plate would affect the actual power of the car since now you are restricting air flow...

rx slim

I'm sure it will reduce HP a small amount, but the amount I'm gaining now going all the way through third gear without the fuel cutoff will far out weigh the small amount I lose with a little bit of exhause restriction, I would think. Gotta find some nice long stretches of road to really redline through the gears now.

JyRO

iTrader: (3)

Wow, what can I say to this? I'm not too big on the props, I appreciate it though. But what I am big on is that I'm glad your car can be ran hard, like its meant to be. The middle plate is a ~ 2.25 inch port. I can make plate at in-between sized if needed.

KaiFD3s - Does it reduce power? That's a good question. I would say one answer would not be sufficient for every circumstance. What happens when you creep? Well, you're getting more air (overboost), so you're getting leaner. When you get to a certain point lean, you will lose power. So if you keep your car at a lower boost, you will keep a more desired AFR for power. So, at least in some cases, using this plate, and being able to stay at WOT and no creep will give you more power. Of course an AFR meter will be the ultimate answer.

If your a car has been 'tuned' for higher boost, and is adding fuel, and keeping a set AFR range, then adding any restriction would not be ideal. But in most of the cases I've read on this BB, these plates are going to improve your condition, give you more power, decrease the damage you can do to your engine by creeping, and allow you to keep your foot planted and not worry about boost problems, if your racing say, an S2000.

Advantages:

• They weigh like 2 oz. compared to what a cat weighs (~40 to 50 lbs?)
• No modification to the exhaust needed, compared to adding a cat
• These plates will never go bad, as compared to how frequently a cat will go bad
• Cheaper than a cat
• A truck load easier than wastegate porting work
• A truck load cheaper than wastegate porting work

I hope this helps!

- JyRO

audiobot7

Nice

Efini_7

iTrader: (1)

So if you're running the factory ECU that's probably a good solution. Otherwise i'm sure there are better ways to go. But good work. Seems like for this particular situation that was a very clever solution.

DigDug

Doesn't matter what ECU you run. If you're getting boost creep, and you don't want to port the wastegate, these plates are a great solution.

I bought a set of these from JyRO as well, and they're very nice! Much higher quality than I expected. They're stainless, so they'll stand up to condensation/corrosion just fine, and they appear to be thick enough to take the heat.

Interestingly enough, the 2.25" works for everybody I've heard from - that's the size I ended up using too, after trying the 2.5" and still getting some creep up top. The 2.25" completely eliminated my boost creep, even at 13PSI in very cold weather. I put it at the rear flange, between the midpipe and cat-back - I figured I might as well put it as far back as possible to minimize the heat it's exposed to...

Like I said, works like a charm. I just did a dyno session last week, and I've been running the car pretty hard since, and boost is rock solid. Nice work, JyRO!

BoostCrzy

i made my own plates about 2 years ago for my car...same problem.....but in the end i noticed the turbos would spool considerably slower with the restrictor plate in place....when i removed the plate the spool was much quicker....but the boost would creep of course.....you could also accomplish the same thing by using the stock airbox and filter...my current setup is @15psi and i no longer need to cope with these issues...but i figured i would share my experience.....i feel this is a great "temporary" mod to keep boost under control...but you can effectively do the same thing with either a stock cat-back or midpipe......

JyRO

iTrader: (3)

BoostCrzy - I put my stock filter and airbox back on. It didn't help me with my boost creep. I tried it with/without the stock filter and airbox with the big plate. It made no difference for me. When I put the intermediate plate on, boom the creep was gone. I haven't had my FD long enough (plus I'm battling cooling system problems since then) to judge the spooling.

rx slim & dig dug - Did you guys notice any difference with quickness of spooling?

- JyRO

BoostCrzy

yea....some cars are healthier breathers than others ....lol....either way....boost creep is bad.....but i feel the average loss in the midrange was a bit excessive.....of course...my setup is Non-Seq. so midrange was greatly improved with free flowing exhaust....

DigDug

Actually, since I was going from cat to midpipe, even with the addition of the plate, boost comes on much quicker.

People are always quick to point out that you're adding restriction to the exhaust, after opening it up by going to a midpipe. But it's important to remember that, even though you are restricting flow somewhat with the plate, you're still gaining a significant amount of flow simply by removing the catalyst from the equation. There's plenty of documentation out there which illustrates how restrictive a catalyst brick is, and you'd have to restrict the exhaust much more than the 2.25" plate does to match the restriction of a cat. FWIW, the metallic ones are better, but you're still running the exhaust through a screen...

If you're comparing the restriction of a wide-open midpipe to one with a restrictor plate, of course the plate adds restriction, but if you can't consistently control boost, what difference does the extra exhaust flow make? It's a loss, because without the plate, you have to shift at 5.5-6K to keep from overboosting and blowing your engine! (hypothetical value used here to illustrate a point)

Of course, the alternative is to port the wastegate, which is a lot of work and has its own side effects. I prefer not to go that route, at least as long as my turbos are working and don't need to be taken out.

It's unfortunate that we so easily hit the limitations of the stock turbo control system, but then again, the control system was never designed to be run without a cat! The stock wastegate port size is perfect for the factory configuration.

And BTW, I'm running RZ turbos, which apparently suffer the same wastegate port size limitation as the USDM turbos...

KevinK2

Interesting, as the oem dp, cat, and muffler flanges have built in (weld deposit) restrictions that measure about 2.25".

rx slim

I am still doing some tinkering with my boost controller to get it 100% perfect, but I haven't noticed any significant change in my spool rate. I am just so happy that after having my car for about 2 years, I've finally done something about this boost creep and can run my car. Great stuff, and an easy fix. Of course, in the future I am considering getting a FC Commander, and porting my wastegate, but that's a future time when I accumulate a little more play money I can hide from the wife. Right now, this is the quickest, easiest fix possible, and it works like a champ. Again, the man is a genius.

Narfle

iTrader: (16)

Im sure that this would reduce power seen at any given boost level
But! Now that the car no longer overboosts it can be set to say 13psi until redline whereas before it would have to be set to 10 to creep to 13 by redline and thus increasing power over the lower end of the band. But I am guessing that peak hp would be knocked down a notch or two due to the lower efficiency of the exhaust system.

JyRO

iTrader: (3)

Barban - I wouldn't be too sure about that. Because, in many cases as an engine starts to overboost, the ECM will not be adding more fuel to keep a set AFR (an AFR that achieves maximum power). And as you get leaner away from the optimum AFR, the power will drop off. The proof of this is, how many engines have been damaged from running too lean (especially combined with when it was able to boost over 10 lbs.)?

Admittedly, I'm not 100% sure on the above train of thought, but it makes sense, explaining why these engines fail from a leaness/overboost issues.

- Jason

BoostCrzy

the rotary engine loves to stay rich....but wil make more power as it gets closer to stoich..(14.7/1)....unfortunately the rotary also is prone to failure as the combustion temps soar(getting lean)...so the only way to keep the internals happy and safe is to keep them wet(rich) and cool.....i personaly opted to add 2 extra 720cc injectors with a controller to work seperately from the stock ecu so that i could retain the great driveability of the stock maps and add fuel for those 15psi hits....the injectors in conjunction with a supra fuel pump and a blitz sbc-id allow me to maintain a consistant AFR of 11.0-11.2 to 1.....all the way to redline.....and i tweaked the map to dump right before the stock boost sensor hits the top(16psi) keeping things wet just in case.....duty cycle on the turbos are set to 54 and they are in non-sequential.....i have been running this setup for 3 years and can say it works FLAWLESSLY for me....i dynoed once in 92 degrees @12psi (clutch would slip after 12psi...have since replaced with act) and a heat soaked SMIC with no fan yielded 309whp...

never underestimate the stock ecu....just give it a friend or 2 to play with

Narfle

iTrader: (16)

Right, The optimal a/f is 14.7 for power. For reasons of detonation our cars chill between about 10-12afr's under boost. As one boosted past the 10 or 11psi potential of our ecu you would lean out and lose power. But the period between overboost and a blown engine is of little relevance as this would result in one run per engine. So forget losing power due to a lean tune. What I am saying as that at any given boost level on the engine the effect of exhaust restriction will be a loss of power.

BUT, for that you get to keep your engine
AND you can hold this psi to redline without tuning for surge which I beleive would net you a much broader powerband. Which is what were all really after right? Safe, predictable power. I'm going to use a ristrictor plate to set my turbos for 13psi and a pettit ecu. Without the restrictor I would have to tune my boost control to 10psi so that it would creep to 13psi by redline which risks overboosting. With this restrictor I can just set the boost to 13psi and not sweat because I have enough exhaust restriction not to creep past 13psi.

JyRO

iTrader: (3)

I can't argue with any of that ... makes sense to me. I know that for me I want to keep ~10 psi so that I can keep my foot to the floor to get all the power for as many times as possible. My restrictor plate helped me achieve that.

- Jason

rx slim

I'm planning on adding a flux capacitor to run 10.21 gigawats through a gyrocoil on the distributor flipper flapper. Should reduce my metabolic pressure rate by 30%, causing an influx of hyperspin thus resulting in 2 extra whp.

Just kidding. You guys are a little over my head, but I enjoy the read, and am learning all the time. I do know that I had a major problem with boost creep since I bought the car, with a lot of mods completed before I bought it. This 10 minute fix was a dream come true.

BoostCrzy

lol...yea...it can be confusing at first....but i gaurantee you will come back to this thread later and understand...lol

JyRO

iTrader: (3)

Guys - I was on vacation the end of last week. A couple of guys were PM'ing me. If anybody has any questions for me, ask away.

- JyRO

silverTRD

iTrader: (37)

[QUOTE=rx slim]I'm planning on adding a flux capacitor to run 10.21 gigawats through a gyrocoil on the distributor flipper flapper. Should reduce my metabolic pressure rate by 30%, causing an influx of hyperspin thus resulting in 2 extra whp.QUOTE]

lmao...

jyro, pm sent

JyRO

iTrader: (3)

silverTRD - I worked for TTC previous to my current employer :yuck: . If you happen to know what TTC is, then I am assuming your Torrance location and TRD is related. Do you work at TRD?

- JyRO

Narfle

iTrader: (16)

Im running a downpipe to a midpipe to the greddy SP2 exhaust. Needless to say I was the victim of a little boost creep. I pm'ed JyRO after seeing this thread and he hooked me up with three restroctor plates. I got up under the car and in about 5 minutes I defeated my boost creep. I noticed an increase in low end power. No decrease in spool time. And only a slight loss of power through the midrang. I can floor my 7 whenever, wherever in whatever gear care free. I run 13psi to redline. Its a beautiful world. You can try your hardest to clog it up with cats or resonators but when it comes down to it this is the cheapest, simplest, most effective method to never worry about boost creep again.

JyRO

iTrader: (3)

Glad it worked for you Barban. Seriously, try the next larger port size ... you'll get your midrange back and I doubt it'll creep. Its definitly worth a try.

- JyRO