964-C2

Will I need a new tune (ignition timing) if I change my "small" turbo with a "big" turbo?
I have a Vitesse Maf-kit, so I am able to adjust afr's.
Thanks.

944Phil

I'm also interested in this. I have an m-tune installed and asked Josh about it. This is what I understood: the computer monitors the air coming in and provides fuel accordingly.

But at what point do you need to re-tune? Especially considering that the car runs open loop at full throttle.

Dougs951S

Lots of factors (fuel used, shape of combustion chamber, compression ratio, cam selection, to name just a few) effect what kind of ignition maps you can get away with but generally, a bigger turbo isnt going to have a dramatic effect. If you have a safe ignition profile now, retune to get the AFR's in check and you should be good to go.

numbskull

With larger turbos tuning fuel was a big part of making it work smoothly. Never really had issues with ignition other than watching plug condition but did upgrade the coil. Use a WB 02 to monitor what is going on.

bw993

I have a M-Tune that I have run with a K26/8, K27/8 and now a Garrett, with no issues based on my AFRs. You need to make sure you have a WBO2 and a reliable way for monitoring and controlling your boost levels.

Thom

Yes.

blown 944

Not with the m tune. That's the purpose of using MAF and map sensors and having large mapping to accommodate various pressures at rpms.

black944 turbo

As Sid stated, that is one of the selling factors Josh used is that the m tune can accommodate for different turbos. I am not sure about the vitesse system though.

fast951

If you have the V-FLEX or V-MAF+ software you'll be fine. Both use a MAP sensor to alter ignition/fuel based on actual boost. So look for the MAP sensor..

If you have the older software, more than likely you'll be ok, but not ideal!

fast951

Been doing this since 2007 when we introduced the V-FLEX software so the DME can alter ignition and fuel based on actual boost.

azbanks

If you have a Vitesse MAF kit, you should have a Vitesse turbo(IMHO).

I have a Vitesse stage 2 turbo for sale.

fiily

I bought the vitesse MAF off of a member here, is the above a true statement, or can I use another's turbo for my turbo upgrade?

azbanks

Sorry for the confusion, you can use other turbos. I'll change the wording to avoid the possible that anyone else reads my words and assumes bad info about John's products.

I was trying(and apparently failing) to be funny. I do have the Vitesse stage 2 for sale if anyone is interested. I got 323 RWHP with it and a few other mods.

fiily

No harm, no foul. Hopefully Santa's(wifey) nice to me this year and buys me a new turbo, otherwise I will have to save for a bit, then buy one.

333pg333

Bear in mind, most other turbos probably won't fit without quite a bit of fabricating and other things to consider. Getting a turbo to bolt on will make life quite a lot easier.