E85 Now Boost Creep Issue

[JH32]

Hey guys

Last week I had my cams dialled in (HKS 272s) and then put on the dyno for an E85 tune. Relevant mods are:

GT35R

Turbosmart 50mm progate (located not up top but down near cross member)

6boost manifold

I received a call on Friday afternoon from the tuner to say that they weren't able to control the boost and they had to take it off the dyno. The car has always had a bit of a boost creep issue, though the problem seems to have been exacerbated by the cam dialling in and the ethanol (don't know how though). It was suggested to me that the wastegate wasn't handling the new setup well and that it might be faulty.

So, could it be that the wastegate is faulty and somehow whatever fault it had before has been really brought to the fore now?

Or, could it be that the wastegate is in the wrong position? I often see wastegates up near the turbo however whoever installed mine has it right down underneath the manifold and turbo, almost near the cross member...just looks wrong to me.

Weird that it went so bad after the cam degreeing and the change to E85...

Any input appreciated.

[GTSBoy]

Yeah, of course. It all depends on whether the WG offtake in your exhaust manifold is well done or not. It it is poorly located in some way then it won't flow as well as it should, and even a big fat 50mm gate won't help.

Given that it's a 6Boost manifold, it shouldn't be that wrong. Has it been modified to put the gate where it is, or was it originally laid out that way? Got photos of it off the car?

[scotty nm35]

As above, the gate needs good flow. If the gasses have to do a 180 to get out the gate it just won't work well, as you have found.

Do you have pictures from the installation?

[JH32]

I've taken a couple of pics tonight of the setup and attached.

You can see that the pipe to the wastegate exits the manifold near the collector then takes a 90 degree bend downwards to follow the dump pipe. I don't think the manifold itself has been modified in any way but I'm guessing the wastegate was originally intended to be fitted quite near to the collector? Only problem is, I don't see that there's a massive amount of room to fit the WG, which is probably why they've mounted it so low down. Excuse the oil in one of the pics, had an oil leak which was fixed last week.

[black bnr32]

the offtake is too far from the front cylinders.

turn the boost up

[methz]

what kind of boost control are you using? is the wastegate set up properly using both ports? 50mm gate and that positioning should be perfectly fine.

[scotty nm35]

Do you have the graph? What boost wat is running, and what did it climb to?

[JH32]

what kind of boost control are you using? is the wastegate set up properly using both ports? 50mm gate and that positioning should be perfectly fine.

I'm using a Greddy Profec B Spec 2 and yes I believe the gate is using both ports.

Do you have the graph? What boost wat is running, and what did it climb to?

Originally i.e. before the E85 tune it was running around 20psi. Apparently it climbed to about 1.6 bar and they couldnt stop it, the boost just wanted to keep climbing. I didn't get a graph of this most recent trip unfortunately as they pulled it before doing much of a tune and sent it home on a flatbed.

I emailed Kyle from 6boost and he suggested removing any extra springs in the WG and leaving a 7psi spring in it as extra springs limit the valve travel and can make boost creep even worse. I don't know what spring(s) is in there at the moment but would this help?

[Hanaldo]

Haha mine did the same thing man, though I don't have a 6boob, just gate off the turbo housing. But it's always held boost dead flat on 98, then had the flex fuel done and it now creeps from 21psi to 25psi. My tuner thinks the wastegate is too small (Turbosmart CompGate 40) and the screamer pipe coming off at a 90 degree angle isn't good for flow. So I will sort those out, but they have always been like that and always held boost very well prior to the ethanol.

[scotty nm35]

I have never had an issue with my gates off the turbo Martin, but I do die grind the inside to flow nicely. It's all about the flow at the end of the day, not pressure or size.

[KiwiRS4T]

That right angle turn won't be helping but looks like a nightmare to change or even work on. Try the mods as suggested by Kyle.

[Hanaldo]

Yeh your exit pipe is much better than mine. Mine is a sharp 90 degree angle, straight out of the wastegate:

Horrible for flow. My fabricator has had all the stuff to make me a proper one for well over a year now, but between him being busy and my car not running, I haven't managed to get it done yet. I'll do it before finishing off the full E85 tune and see if it helps, but the fact that it never had an issue on 98 fuel is puzzling.

[JH32]

Haha mine did the same thing man, though I don't have a 6boob, just gate off the turbo housing. But it's always held boost dead flat on 98, then had the flex fuel done and it now creeps from 21psi to 25psi. My tuner thinks the wastegate is too small (Turbosmart CompGate 40) and the screamer pipe coming off at a 90 degree angle isn't good for flow. So I will sort those out, but they have always been like that and always held boost very well prior to the ethanol.

Such a pain eh! So weird that it happens when introducing ethanol. That bend on yours does look rather nasty mate!

Just spoke to the workshop, he said bring it back and he's going to pull the wastegate off and give it a bit of an overhaul, change the spring in it and then we'll get it back on the dyno. He said he's had a number of cars over the years with the wastegate in that position and he hasn't had a problem so he reckons the wastegate is definitely the problem - could have a sticky valve he thinks.

[Ben C34]

Why didn't he just do that instead of sending it back on a truck? That's kinda annoying that he knew it was something simple but didn't do it.

Edited October 7, 2013 by superben

[JH32]

Why didn't he just do that instead of sending it back on a truck? That's kinda annoying that he knew it was something simple but didn't do it.

To be fair 'the workshop' and 'the tuner' are two separate businesses so the workshop did the cam stuff and cam belt change and the tuner was doing the re -tune. Ah well! Will get the springs looked at and go from there.

[Ben C34]

Ahh, that makes sense. All the best getting it sorted.

[GTXR34]

we are having the same issue on a mates car.

6 boost with a 50mm gate and gtx3582 and runs fine on 98 but as soon as we tried to get it on E85 it just spikes..

we figured it was the position of the wastegate as its at the back of the manifold too

havent sorted out wat to do just yet.. thinking of maybe running another gate at the front of the manifold or maybe just upgrading to a 60mm gate..

[scotty nm35]

The GTX35 rear I posted above ran a 40mm gate, with absolutely no issues. You are correct, it is all about placement and flow, a 60mm gate may be exactly the same...

And let Kyle know his manifold won't hold boost well. Without everyone giving feedback he may never know his wastegate path design is flawed. I have dealt with too many of his mani's lately with similar issues, but apparently he is the guru and that can't be the problem...

The split pulse 6 boost manifold with twin 40mm gates worked fine, but what a bugger to fabricate.

[Hanaldo]

But why would it be an issue on E85 and not 98? Mine worked well on 98 but not at all on E85. Is that because the extra fuel required with E85 means more exhaust gas, even at the same power level?

[GTXR34]

yer theres a lot more exhaust gasses with e85..

we did let him know and he said it was all in the tuning and it was left at that..

ive heard he was really up himself and always backs up his manifolds.. im all for feedback but only when it makes a diference..

ive personaly got a split pulse t4 6boost manifold and the wastegate is placed right in the middle of all the cylinders.. we are expecting this to work fine but wont find out for another coupe of weeks..

Edited October 11, 2013 by GTXR34