.48 A/R turbine, .60 A/R compressor-Running out of juice at 5k--suggestions?

[WDRacing]

HACK the MAF...heh. Save the money for your new exhaust.

Lesson learned here, everyone who posted had valid points. We need to be able to see outside the box. I'm not Jesus when it comes to motors and boost. I might like to think so somtimes, which clouds my judgment. We can always learn a thing or two from the next guy.

Some manual BC's aren't very good, however I ran a TurboXS on my SKyline for 4 years at up to 28 psi with no problems.

WD

[TrunkMonkey]

Lesson learned here, everyone who posted had valid points. We need to be able to see outside the box. I'm not Jesus when it comes to motors and boost. I might like to think so somtimes, which clouds my judgment. We can always learn a thing or two from the next guy.

ain't this the truth.

MarkEmark, if you should happen to the nice gentleman who did your downpipe again, give him one of these :bash .

i'm glad you got your problem solved.

-demetrius

[huguetpj]

Mark... Summit sells some of those Y pipes. I believe up to 2 1/2". I would by one, but they ain't got them in 3" and I've already have my cat on flangers.

Since we are on the subject of exhaust. The other day I went to the track. Usually, on the street with my SBC off, boost goes up to 5PSI (maybe a few peaks at 5.3PSI). At the track I removed my cat in essence running an open 3" downpipe. What a sound!!! :pface Anyway, now my boost went up to 6.7PSI.

Should running an open downpipe do that? I mean, I thought I had purchased the 0,3Bar spring for my WG, I'm not sure anymore, but should boost change cause of the decrease in backpressure?

Sorry for the hijack Mark.

[MarkEmark]

I noticed mine increased about one psi as well, so I turned down the boost one pound. I think it may be a common side-effect.

Unfortunately, my problem is only diagnosed, not solved

And even though I know it's not the mbc that's creating the boost fall-off, I still would rather have a "more-refined" system of delivering boost--but cheaply. Who makes the best/most effective manual boost controller? I know they range from a simple needle-valve to something a lot more complex--What were you running WDRacing?!?

[huguetpj]

I don't think there is much diff between MBCs. But I would stay away from the bleeder types. The others most probably would work quite the same

[j-z]

so does the boost still drop off at the higher rpms?

[sil80drifter]

When you remove the restrictions from exhaust/intake, your boost goes up, no matter what the stock wastegate setting is (if it isn't controlled electronically). Think of it this way: The wastegate is made to produce 6 psi (example not actual number) under certain conditions, like a car that comes with a turbo has a certain exhaust, a certain backpressure to it, and etc. Now you modify the exhaust and let the turbo run free-er. The wastegate now sees less "buildup" of pressure and opens later, creating higher boost numbers. My friend ran his stock RX-7 (2nd gen) at 6.5 psi. Then he freed up his intake path with a custom air intake and his boost jumped to 9. That wasn't good so he had to undo the intake. Same with exhaust, my other friend just turboed a car with a turbo from another car which was supposed to run 6.5 psi stock. He did put a large exhaust on it, without a cat and the bost gauge read 10. Neither used boost controllers of any kind.

sil80

[huguetpj]

Thanks. Sounds about right

[j-z]

the thing that youre looking for for your exhaust is called an e-cutout. i think they have some on ebay. its electronically controlled so all you have to do is flip a switch. but i have heard some stories about these though. if its really cold where you live then stay away from these. they will cause problems.

[TrunkMonkey]

to sum it up in two words...boost creep.

remove your boost controller and let the wastegate do all of the work. depending on the wastegate your using, you should stay at or around the same boost level. do something as drastic as remove your exhaust without using a boost controller, and the wastegate now becomes too small to keep up with the amount of air being pumped through the turbine. how much more boost depends on the size of the wastegate. the larger the wastegate, the less boost you will create past the set psi.

-demetrius