Not sure there is much point in a GT3071R on your car, you can make more power on your current setup with headwork so it seems a pointless exercise.

Nigel, your best option is probably an external wastegate and a decent equal length manifold not a bigger turbo if you want the lag to be no worse.

VGT isn't an option - I've spoken with turbo Dynamics this morning

I'm faced with the traditional choice of better top end taking some bottom-end tractability away

I love the top-end rush of a big turbo, but I'm not willing to suffer any worse lag than I currently get, so it would appear that I may still have my ideal turbo

John - thanks for the suggestions - I know that your transition to external wastegate was rewarded with a jump in power, so maybe this is the way to go - I'll empty the piggy bank to see what's in there

I await Luke's results with eager anticipation...

you could get turbo dynamics to supply you a ported shroud. May make a bit of difference. On my turbo I have one that improves the spoolup by about 2-300rpm I'd guess. basically it spread the whole compressor map so I got both more low-down and more top end out of it. That's how I ended up with a GT3082R with the same spoolup as a GT3076R more or less

Don't really know how the 28RS looks but the 28R has a real mismatch to the Fiat manifold - easily fixed tho.
Maybe that's what you meant John.

valid point, but that's not what I meant. I mean the compressor inlet from the inlet tract/SIP whatever people have.

I thought a ported shroud helped with surge? If anything I was under the impression that it increased spool slightly (as in later in the rev range)?

the gt30 is on tbh its no biggy if i end up finding the gt30 is overkill as to put it. . . . il just sell and get smaller turbo

but untill thursday afternoon after ive been back to leighton for fueling tweaking. i wont know what its like as ive hardly even went on boost earlier today on way home from nobbys due to not knowing how AFR been affected!?

have you ported the wastegate?

you make it sound soo easy no and how would i?

the 3071R has been known to boost spike as the wastegate can't control the boost, this can be cured by porting the wastegate.

You can do it yourself, but I sent mine off to Turbo Dynamics so I knew it was getting done properly (and because I'm lazy)

how much did that cost if you dont mind me asking?

£80 I think, I got the compressor shroud polished whilst I was at it which was an extra £10-15!

luke - is leighton putting you on the RR too? be interested to see a graph if so.

Right. Especially if Luke wants to run low or mid boost

Like Leighton advised me, if you are going to run high boost you don't care about boost creep... but if you don't want more than 1.2/1.3 bar you'll probably need a little porting.

Mine creeps up to 1.7Bar without the porting but that’s with a 3” system. So I can't hold less than 1.7Bar to redline at WOT even if it set the boost to 1Bar. If this is the case with the GT30 with you exhaust then you are in trouble if your aiming for 1.4MAX.

which turbo is that with J?

2871R

Hi,

I don't have any problems with boost creep what so ever with GT3071R-WG 0.86 turbine housing.
With the 0.64 housing I have heard that to happen.

I use Apexi AVC-R and it can handle programmed boost level without problems.
For example at the moment I ran "only" with steady 1.3 bar boost and the variation is only some 0.2 bar vs. set boost value.

-Jari-

The one thing I have never done is port the wastegate, never needed to. This is with a GT28RS 0.86, GT2871R 0.86 & 0.64, GT3071R 0.64 and GT3076R 0.64 which I currently run.

rog, no not booked for rolling road on thursday but will arrange one very soon. Just need to know fueling is perfect for whatever boost my setup allows me to run then after that it will be down to engine holding out. im using blitz boost controller and am pretty sure it will keep good tabs on any serious boost spikes as it will cut boost if it tries goin over 1.5bar so we shall see if it keep cutting my boost i know whats trying to happen.

I know Matty was having problems until he ported the wastegate. Did Fergie not have the same problem aswell? Where has Fergie gone?

That's ok then as Luke has Matty's turbo!

Nigel doesn't get any issues with his GT2871R 0.64, I didn't have any problems keeping the boost down with Westcoupes GT3071R 0.64 either. I would say TurboJ your problem lies elsewhere as that is an extreme case of boost creep!

Panic over!

Who said I have a problem . It is down to the fact that I have a 3" free flowing exhaust. Less back pressure more chance of boost creep. Porting the WG will simply solve this or revert back to my old 2.5" system. My case is a bit extreme but the point I am making is that IF luke does encounter creep it will be a problem whereas mine is fine because I’m mapped to 2Bar.

You shouldn't get it that bad though. I have a full 3" downpipe off the turbo, not a 2.5" tapered downpipe but actual 3" right off the turbo all the way to the decat pipe which is then 2.75"... never had any boost creep, I can run 1bar to the redline.

Oh and that's a 7800rpm redline too!

It does help with surge but it depends on the design if it increases or improves spool. The more old school ported shrouds just move the whole volumetric efficiency of the turbo (i.e. moved the whole compressor map to the right) but there are some modern designs out there that spread it/stretch it.
Mine was proven to improve spool as I did do a before and after.
I wouldn't buy a turbo without it now tbh.
It isn't just a case of polishng the shroud, although that itself can improve spoolup slightly. It is basically adding a seperate port between the compressor cover and where the majority of the air goes in. The designs vary quite widely - mine is basically a totally seperate cone sitting inside the standard shroud.

I think a lot of you are missing a trick with some of the options around the compressor housing - be it porting or the availability of larger compressor housings like the T04S style 0.70A/R housing. It's all well and good being a bolt on king but you can get more bng for your buck if you think a bit more about your options.

This can be a good idea to avoid boost creep too :

http://www.atpturbo.com/Merchant2/mercha...tegory_Code=GTH

But something seems to be wrong with this. If this part is exactly like on the pics i think it won't fit on our cars. The "hole" on the housing is going to be in front of the engine And WG will be impossible to fit.

An "opposite" version of this part would be great!

i had know problems with boost creep,i found if i turned my avcr off my car would run 0.7bar to the redline,its all down to your actuator really

I buying Luke's GT28RS and now wondering if it would be worth having any work down to it prior to fitting. What do we think then guys?