Marc's 1990 4.2L V8 Twin Turbo Coupe Quattro

pkw · Post by **pkw** » Tue Nov 06, 2007 9:51 am

just throwing it out there but you were on the dyno and probably took measure to assure that is was not slightly over advanced timing causing some knock sometimes, hurting power. that is the knock prone area of the rev range but also the area that is the most demanding on coils. personally i did not have real great luck with different coils until i went with the 034 coils (knock on wood) but i never tried using the coils you speak of. BTW a couple of t28s or k24s would hit those numbers and spool up a lot quicker. not that the internet likes to ever hear talk of using small turbos. :wink: your turbos would be pretty nice on a 4.2 though.

p

pkw · Post by **pkw** » Tue Nov 06, 2007 9:55 am

i would not think that a properly sized t3 would take more than 3800 rpm on the street to hit target boost. yours looks a little soft for some reason for sure.

pkw · Post by **pkw** » Tue Nov 06, 2007 9:58 am

Post by **Marc** » Tue Nov 06, 2007 10:27 am

electronic boost control for sure, boost controllers were set flat closed (80% duty) fully across the map so the only thing I could think of would be if the wastegate was creping open. I suspect 'round 3' might involve some stiffer wastegate actuators. Naaaaaaaaate? 8-)

Post by **Marc** » Tue Nov 06, 2007 10:34 am

dual N75s.

From my experimentation 80% duty is the same as 100% but I will do that and see if I notice any difference anyway.

Would be nice if these internal wastegate actuators offered a way to supply boost to the upper chamber :mad:

JasonAG · Post by **JasonAG** » Tue Nov 06, 2007 11:27 am

a4kquattro wrote:anybody seen this happen to an audi rear subframe on a non-rally car???

yikes.

when i bought my coupe the rear subframe was pretty much exactly like that...

Audilard · Post by **Audilard** » Tue Nov 06, 2007 11:35 am

That's 91 octane right? :wink:

Post by **Marc** » Tue Nov 06, 2007 11:36 am

hmm, well before I go that route I'll try disconnecting the wastegate lines alltogether and see what difference that makes.

Now, onto some :pics: and :vids: from the dyno

Haydn checking in:

hard at 'work'

yeah, my car gives me wood. I hope thats normal. "If erection persists for more than 4 hours..."

and lastly, :vids:

http://www.theswansonfamily.us/modules/ ... 020310.MOV

This particular run is an example of the dip in action, you can actually see the car load and unload at the top of the powerband.

Post by **Marc** » Tue Nov 06, 2007 11:39 am

Audilard wrote:That's 91 octane right? :wink:

93

Post by **Marc** » Tue Nov 06, 2007 11:40 am

bradyzq wrote:What ramp rate were you using? That can affect the boost curve.

Not sure, I'd have to ask the dyno guys.

pkw · Post by **pkw** » Tue Nov 06, 2007 11:53 am

newt wrote:MBC?? Why on earth would you want/need one? With a programmable setup you can ramp up the boost much faster and more tailorable than pretty much any MBC out there.

more tailorable yes, if that is what you want to do but the best electronic compared to a simple check valve style MBC (not bleed) located in the right place is pretty much a neck and neck match for boost response and stability.

pkw · Post by **pkw** » Tue Nov 06, 2007 11:54 am

...and way better than any valve that you can not even fully open or close like the above n75.

Post by **HT Motorsport** » Tue Nov 06, 2007 11:56 am

"yeah, my car gives me wood. I hope thats normal. "If erection persists for more than 4 hours..."

I am still walking with a limp

WAUG0806 · Post by **WAUG0806** » Tue Nov 06, 2007 1:53 pm

a_CQ wrote:Nice, very nice! I want that torque curve.

me too!

Nice pull... did you notice a similar dip in power on the track...?

RS · Post by RS » Tue Nov 06, 2007 1:57 pm

timmmy wrote:"yeah, my car gives me wood. I hope thats normal. "If erection persists for more than 4 hours..."

I am still walking with a limp

er, the motorcycle ride there was just really cold....

Was a good time. Next time I'll bring more ear plugs.

Audilard · Post by **Audilard** » Tue Nov 06, 2007 2:07 pm

a4kquattro wrote:
Audilard wrote:That's 91 octane right? :wink:

93

Nice!!!!

vwhammer · Post by **vwhammer** » Tue Nov 06, 2007 3:28 pm

Could you give me a quick rundown on the specs of your engine and the turbos you are using.
If I am reading things correctly all you did (loosely speaking) was stack gaskets on a 3.6, add a pair of t3s and you are making 411hp.

Am I correct in assuming that most of the hard parts of the engine are otherwise stock?

You mentioned that you thought the turbos were a little off.
What would you run if you had it to do all over again?

Do you think there are any junk yard turbos out there that could get you similar results?

84urq20v · Post by **84urq20v** » Tue Nov 06, 2007 3:35 pm

newt wrote:Ahh, yeah, the N75's bleed through even at 100%, you can't fully open or close them, so there's always some reference pressure to the wastegates. We've got some discrete switching valves that really need to be put on the website... :-P

No intention to threadjack , but more info please!!!

Brandon

Derracuda · Post by **Derracuda** » Tue Nov 06, 2007 3:53 pm

vwhammer wrote:If I am reading things correctly all you did (loosely speaking) was stack gaskets on a 3.6, add a pair of t3s and you are making 411hp.

i wouldn't say that all he did was stack the gaskets and throw turbos on...

there's a ton of fab work on this job, more so than any 20vt or 20vt install, and it should be noted so that not just anyone reads this and thinks "hey, i'll do that this weekend"

Post by **Marc** » Tue Nov 06, 2007 3:58 pm

vwhammer wrote:Could you give me a quick rundown on the specs of your engine and the turbos you are using.

bone stock 3.6, stacked head gaskets, head studs, 034 v8tt manifolds, T3 .60 A/R turbos.

Lots of other 'little' mods here and there.. intercoolers, oil coolers, oil/coolant supply and return, etc. But yeah, the motor internals are bone stock.

If I am reading things correctly all you did (loosely speaking) was stack gaskets on a 3.6, add a pair of t3s and you are making 411hp.

Am I correct in assuming that most of the hard parts of the engine are otherwise stock?

correct.

You mentioned that you thought the turbos were a little off.
What would you run if you had it to do all over again?

depends on who's paying the bill

cost no object I would probably setup a sequential turbo arrangement, something along the lines of a GT2871R as the larger turbo and a GT2860 as the smaller huffer.

Another approach would be for me to go with the 4.2 which would have the larger displacement necessary to spin these turbos up faster. Either way, ball bearing is the way to go, I just couldn't justify the $$.

Do you think there are any junk yard turbos out there that could get you similar results?

I think a pair of K24s wouldn't be a bad choice, DEREK

Post by **Marc** » Tue Nov 06, 2007 3:59 pm

WAUG0806 wrote:
a_CQ wrote:Nice, very nice! I want that torque curve.

me too!

Nice pull... did you notice a similar dip in power on the track...?

On the track I was only running 15psi, and didn't notice any power dip.

a_CQ · Post by **a_CQ** » Tue Nov 06, 2007 4:03 pm

there's a ton of fab work on this job, more so than any 20vt or 20vt install, and it should be noted so that not just anyone reads this and thinks "hey, i'll do that this weekend"

"..loosley speaking" and somebody could do this to a motor in a V8 already....I think that's where he was going at...

Derracuda · Post by **Derracuda** » Tue Nov 06, 2007 4:37 pm

a4kquattro wrote:I think a pair of K24s wouldn't be a bad choice, DEREK

we shall know one of these days 8)

fasterthenrs2 · Post by **fasterthenrs2** » Tue Nov 06, 2007 5:58 pm

Hey Marc grate nr, to bad wasn’t able rev over 6K, did clutch hold up on a street??

vwhammer · Post by **vwhammer** » Tue Nov 06, 2007 6:15 pm

What are the K24s on originally?