2006 Noble M400 #141

[A//// Guy]

It would be odd for both to go out at the same time though, id still think one would make some boost if one went bad. Report back with findings!

[cmspaz]

If it's a metallurgical issue, like what MAP had with the EF turbos where the flapper rod actually twisted under higher loads, adding preload to both could hypothetically cause both to exhibit the same failure simultaneously. Food for thought, but I like the idea of getting the DPs off and checking visually.

[Murlo26]

I know almost all of the evo guys running the newer BW EFR stuff ditch their wastegate or their so called "high pressure canister" or whatever they call it. Mainly as it just doesn't hold boost at all. Not sure if they are quality or not or just simply don't have enough spring pressure though.

Might be worth swapping those out if you find them to be the culprit.

[asshanson]

Yea, the Borgs come by default with the "medium pressure" wastegate actuator. Spring without preload is around the 10psi range, and adding preload can set tension anywhere between 10-17psi before it opens. For you crazy DSM/Evo guys on race gas, that's not enough to run 30psi on an internal gate, so they make a "high pressure" actuator that will open between 17-25psi just on wastegate pressure alone, depending on preload.

Obviously a boost controller can prevent the flapper opening until higher boost amounts, but you don't want a 10psi spring if you're running 30psi because exhaust pressure will force the flapper early, this just results in lower boost than desired.

However, this is not my problem, as I only want to run 15-17psi for the time being. And I have 0 psi.
I still have not had time to take the downpipes off, work is killing me. It's 3am and still at the office. Hopefully by Friday evening I will have time to visually inspect the flappers and turbine wheels..

EDIT: Spaz, these were some of the first BW EFR turbos, so it's definitely possible that it's a metallurgical issue with the arm to the flapper bending and now it's always open. Either that or the turbine wheel was taken out by a piece of exhaust manifold breaking off. Those are my two best guesses right now, will find out soon. The noble/rossion manifolds are notorious for taking out turbos.

[Goat Blower]

That seems a bit unlikely though as these were fully operational turbos on someone else's car recently. And the chance of both going out seems far fetched, there has to be something else.

[JET]

Can you do a boost leak test on the system? Any way that upper intercooler pipe change caused an issue? Maybe a coupler ripped?

[asshanson]

Well, it's been a year since I've driven the car, and I had zero time last year, so I sent it off to Ohio to get fixed. Just before the motor popped it started making boost, and the shop found rock pieces embedded in the pistons, and one compressor wheel had a couple nicks. So it looks like a rock or two must have lodged itself in the compressor causing it to not spin, thus the no boost, then broke free and toasted the motor.

Car now has a brand new motor and 1 new turbo, and went to the dyno today for a tune. One of the turbos seems to be not opening the wastegate, it's making too much boost so it'll be another week or two before it hits the dyno again. But this is the dyno graph from the only run (no tuning), it's a little lean but had zero knock at 25psi and 12.5:1 AFR, good sign that it should be a very reliable setup when it's back down to 16 or 17psi and 11.5:1 AFR.

Shootout (dynojet) numbers are 678hp/601tq. That's way too much for a street car that weighs 2400lbs (I'd never get traction), so he's going to shoot for 550whp at 16psi.
http://www.dsmstyle.com/photopost/data/687/noble_dyno.jpg

[1ViciousGSX]

Nice!

[turbotalon1g]

fuuucccc, that's so badass!!
low boost for road course and high boost for slicks and street fun!!!! :drool:

[A//// Guy]

So awesome, hope the wastegate fix is easy and its on its way back to you soon!