Restriction in Peco exhaust

[holty]

Has anyone put a restriction in a Peco exhaust to counter the effect's of over boost cut off? I've got a Everest fitted also, but i get cut out after prolonged acceleration. Porting the wastegate is a bit beyond my skill's so i was wondering if someone has had a go at a restriction? Cheers's Holty

[ailwyn]

Have not done this myself as I have a pre-cat to keep it all in check

I do have recollections of somebody saying that just putting a gasket in the exhaust with a reduced diameter will slow the exhaust down enough to stop the overboost.

I think most have gone down the porting route... again not done this myself, but it looks straightforward (even if it also looks like hard work).

Ailwyn

[GeoffSmith]

Have not done this myself as I have a pre-cat to keep it all in check

So have I, but it doesn't work for me!

I do have recollections of somebody saying that just putting a gasket in the exhaust with a reduced diameter will slow the exhaust down enough to stop the overboost.

A 2" diameter gasket IIRC. I don't know if this has been proven however and I wouldn't expect it to last too long.

I think most have gone down the porting route... again not done this myself, but it looks straightforward (even if it also looks like hard work)

And some of us haven't yet, although I finally got the lower heatshield bolt released.


Porting the wastegate is the best solution as it matches the wastegate to the turbo's increased performance. As Ailwyn says, the process is fairly straightforward and has been well documented; the biggest problem is probably cracking the nuts/bolts.

[Enright]

Yes.

[ailwyn]

Yes.

Wow... that's an enlightening response

[GeoffSmith]

What's the point in wasting words when a load of bollecks have already spoken?

[ailwyn]

Geoff

Are you sure your pre-cat is still stuffed and that the wastegate is opening fully?

Mine has got the everest and peco but only puts out 10bhp above stock - 165 total (as tested on Peco's rolling road), which I put down to the pre-cat being a restriction, which reminds me I haven't nagged Peco Dave about the sportcat for a while

A.

[Enright]

Yes.

Wow... that's an enlightening response

What's the point in wasting words when a load of bollecks have already spoken?

Well I suppose I could have just put (which would have been even less typing!), but I hoped that you'd spot from the POV of someone who had actually DONE the jobs, that the above was spot-on!

[holty]

Geoffsmith, does your car still reach cut off even with the pre cat still on? I've a spare and was going to put this back on to help cure the problem!

[GeoffSmith]

Geoffsmith, does your car still reach cut off even with the pre cat still on? I've a spare and was going to put this back on to help cure the problem!

I'm afraid it does.

It's also been through an MOT so I'm assuming that there is something inside it. That is one of the reasons I was warning that the gasket fix may not be proven as the pre-cat will privide a lot more restriction, closer to the turbo than a thin gasket; it may be an urban myth or someone may have been lucky if they were marginally overboosting.

Let us know how you get on.

Geoff

[holty]

It's a job that's well down on my list, and it's also sounding like it may have to be quite a restriction, but at some point i'll have to sort it. I'll let you know. Holty

[holty]

Do'es anyone know where the write-up for porting the wastegate is? Might have to give it a go. Cheers Holty

[Enright]

The write-up that I did was in the Stiffy thread from here onwards - hope it helps.

[holty]

Thanks

[nitroman]

Has anyone put a restriction in a Peco exhaust to counter the effect's of over boost cut off? I've got a Everest fitted also, but i get cut out after prolonged acceleration. Porting the wastegate is a bit beyond my skill's so i was wondering if someone has had a go at a restriction? Cheers's Holty

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This father/son company made the FCDs for both of my Elans using the Elan specs I provided them. The current cost is $100 plus postage. These are impossible to get from any "normal" source as the Elan powers it with 5V, not 12V. Assuming you routed 12V from another source the HKS one can be adopted, but I wanted to make a 'plug-in' one without screwing with the factory harnesses. Besides, the HKS FCD has rather harsh/bold adjustment indents, instead of an infinately "smooth" slider. The indents went from 4.37V to nearly 5V. The 5V powered FCD I got from SBITS was shite I think, as it returned inconsistent readings for the same input current. There did not seem to be any logical correlation at all, in fact. BTW, you don't want to take any chances on this part! I've used my 1st FCD on one M100 or another for 8 years now. WhiteOakAudio sends you their FCD preset to your desired voltage, so you don't even need a voltmeter. But had I not had one I would not have known that the other units I mentioned were potentially disastrous.

This is not as good/complete a solution as porting the wastegate, but it sure is easier. It is only a sensible solution if you are just barely touching the cutoff, but not if you far exceed it.