jimculp

Oh probably around 1.2 bar from what I've heard. Good point. It might be time to look at turbos again.

Guns951

Wow those numbers sound fantastic! Be sure to post a vid of the dyno run!

JBL930

Jim
I Know you've been to hell and back with the car, I can't remember the name of the thread where you were going through all your troubles, as you know i've had my own nightmares so you're not alone. Can you remind us of your current build, sorry to be a pain

P.S: If you lived next door i'd steel your wheels

jimculp

No problem JBL. Let's see...

3.4 Mahle short skirt "RUF" P&C's
Autronic SM4 EFI with R500 CDI ignition firing twin plugs
3.2 manifold
GT2 Evo cams
K27 HFS
GHL headers and exhaust (no heat).

Those are probably the high points. Here's my last dyno graph:

jimculp

Seems like we'll never get to the dyno, but when we do I'll try to get a vid.

JBL930

What boost were you running on that pull Jim, was it showing wheel HP or had it corrected to the crank figure? Also why did they stop the pull under 6000rpm, it looks like your BHP was still on the rise.
With the Ruf P&C's do they have sealing rings? I'm just curious how much boost you can run safely with your set up, i've seen a well set up 3.4ltr engine (with obviously a way bigger turbo) putting out just over 600bhp on an engine dyno at 1.2bar. Mid low 500's at 1.0bar.
When you built your engine originally what was your power goal?
I'm not actually going anywhere with this, i'm just curious.
I hope the thing stays together for you this time, how many miles have you put on it since it was last rebuilt?

jimculp

It was with the stock spring +/- .8 bar.
It's wheel non-corrected hp.
Not sure about why he stopped at that rpm.
My power goal was actually to match RUF's Yellowbird at 469 hp.
Now I'd like to see 500 hp to the crank.

JBL930

That's great power at 0.8bar, when you think the CTR was similar power but with twin turbos and about 1.2bar
Have you any plans for better boost control, i would have thought that with EFI you would have some electronic way of controling boost, simply for more acurate tuning, just relying on the spring is a bit crude. I took it for granted that most of these aftermarket EFI systems were pressure sensing, you learn something new everyday.
Going from your last dyno run you should be pretty close your goals if you go up to 1.0bar, and now you have plenty of cooling for it, good luck with it Jim, you deserve a bit

jimculp

I do have an Autronic EBC but the solenoid wouldn't trigger gradually- it was either all or nothing and we were seeing spikes of 1.3 to 1.5 bar. In an effort to save time we disabled the EBC and tuned with the spring.

I'm hoping to fix that at our next dyno session.

JBL930

Jim, i found a way of getting rid of the spikes on here, there was a chap on the 993tt board that posted the pics below. They show the N75 frequency valve that the 993 motronic system uses to control the wastegates but it's the same principle, i assume the Autronic solenoid works in the same way basically.
You simply run a manual boost controller in parallel with your solenoid, anything above your preset boost level and it will bypass the solenoid and open the wastegates, anything below it and the solenoid is in control. Really simple solution and it works a treat.
(Where it says "from turbo housing" is obviously just boost coming into the solenoid, probably from your manifold, intercooler or throttle body, i don't know whether your solenoid has the "ambient pressure" sensor like the N75 valve? The ECU probably has a separate sensor for this?)

It would be nice to have the solenoid working properly but this will do the job for you, have a look

jimculp

That's genius. Thanks- very helpful.

DWalker

Jim- I may have missed it but what wastegate are you using? And if you know, how is it plumbed for boost control? I ask because I know of several fairly high-output cars running the Autronic and not having any issues with boost control even running around 2bar (30-35psi).
The above drawing will work for an actuator type WG, but for an external WG it may not work, depending on how the gate is plumbed in. This is because in a typical actuator setup the WG opens simply due to boost pressue, so to control boost you simply have toraise the boost pressure going to the actuator to open te gate (less boost) or bleed off or restrict the pressure to the actuator and the gate will stay closed for more boost. The
The ambient pressure on the N75 port on the N75 solenoid is not a sensor, its the port the bled off pressure escapes.
If you are using an external gate such as a Tial, bleed-off type solenoids may not be able to control boost because they simply cannot bleed off enough pressure quickly enough and the boost spikes. This will almost always happen when the gate is plumbed so that the boost pressure line runs to the solenoid then to the bottom port of the WG only.
For best control, the WG needs to be plumbed as:
Boost pressure source to Tee port 1(on the run)
Tee port 2(on the run) to bottom port on Wastegate
Tee port 3 to WG solenoid "in"
WG solenoid "out" to WG top port

Sory I dont have any cool pictures, but I can try and take some of a car I have at the shop.

jimculp

DWalker,

Pictures would be cool. The plumbing was done per Autronic schematic. The wastegate is the stock unit.

AaronR968

IIRC I sold him a TiAL wastegate could have changed by now though.

Jim, Hope all is well with you!!

jimculp

Hehe. Actually that was the Tial BOV- still have it and I'm (Tracy is) in the process of mounting it on the up-pipe from the turbo to the I/C.