Just wondering if anybody has experienced this:

The car is able to hit full boost (which is @ 5psi) around 4Krpm in 2nd gear.. but by the time it hits redline, boost is down to 1 or 2psi.

I've checked all the hoses and couplings.. all good. the only thing left is the internal wastegate. it's a TD04 mistu turbo ... if the wastegate was bad, could this happen?

Thanks all!

 

 

last time

 

I have the same thing with my TD04h greddy kit!

where the hell is the leak>? but I hold full boost on the highway!! 8-9PSI!!

Tyler

 

fuel problem I'd say. does it seem to bog after 5 psi if you floor it, but you can get full boost if throttle is applied gradually? then you need a fuel pump.

 

ummm I have a fuel pump??? 255 intank

Tyler

 

I have a similar problem. I am putting in my DSM 450cc's in a couple days though, so I'll find out then. Anyone else have any suggestions?

jB

 

I have a FMIC, and I had a similar problem... it turns out that where the charge pipes come up thru the chassis after the IC, the frame had rubbed a hole into the pipe (my pipes run thru the hole where the airbox used to go thru), causing it to peak boost, then loose pressure. You may want to check that.

 

my money would be on the internal WG


Rob

 

Woulnd't a boost controller fix that though? I installed mine today, and it's still doing the same thing. I have a little faster of a spool now; and the controller is controlling the flow now, not the WG.

jB

 

no, not if there is an internal malfunction going on with the WG, just replce it and go from there


Rob

 

I know what you are looking for, it is the same problem that GReddy has on most of the housings where the wastegate opening is. there is a Crack in your housing where the wategate opens. I would amost guarentee that is the problem. The cast iron gets very hot and cracks the wastegate opening on the housing. I have two td05-18g GReddy turbos with the same exact problem. I have a pic of my crack if anyone wants to take a closer look at what i am talking about

 

Yewah he's got a valid point... Ive seen quite a few turbo's cracked on the WG hole in the exhaust housing side...

 

yes, please email me the pic or post it up: bryanrheem@yahoo.com

 

Ya post a pic, I wanna see this!! is there any way to weld your crack?

Tyler

 

 

if the waste gate was the problem, it wouldnt be opening,
and that would lead to too high boost. check all your clamps, but on the other hand if the spring was collapsed then i can see that, but usually when a waste gate fails, it doesnt open causing a high boost problem,
also check the mounting flange in the manifold.

 

i found some cracks in my couplings so hopefully that's it.. if not, i'll be checking the wastegate


[Modified by brcivic411, 5:43 AM 9/27/2002]

 

You can take a punch/chisel and pound along the crack to (in effect) seal it up and stop it from getting worse, or you could get it welded, but that is kind of costly (on cast iron) and then it would have to be machined down to seal with the flapper. I have a few small cracks in mine and it doesn't make a lick of a difference.

I would also say that I don't think there is any way it is a fuel problem if it is running smooth, but just looses boost. that does sound like a minor leak...come to think about it. I doubt it's the waste gate...make a MBC and up the boost a few psi (to 7-9 or so) and see if it still drops off or if it holds a higher level. I'd think if it holds the same boost lever (after spiking to 7-9) that it is a boost leak in the piping/IC...

 

here's the deal.. i 'fixed' the small cracks in the silicone couplings and ran out again... boost still drops off in 2nd gear.. but holds steady in 3rd and 4th gear! any clue why boost would only be dropping off in 2nd gear but not the others?

even if i use a MBC, it's still bleeding off to the internal wastegate so boost will drop off ...

also... my hose that connects to the wastegate actuator came off... i didn't realize this until WOT in 2nd gear was boosting past 10psi!!!! i'm gonna do a compression test tomorrow

 

fixed your problem yet? i'm having trouble too, damn it only boost at 5 and drops to 3 when WOT, and i can get up to 8 when i gradually gas it. I'm using the hallman mbc