NefMoto

Hello,

First of all, I would like to say that the last 3 - 4 days I had been searching for this and haven't found it, for all of you it will probably be a very very basic question, but I would like a recommendation or help (Sorry but I don't want to blow the engine, it cost me some effort to have it how it is now)

After years, I decided to return to my old project a Golf GTI 1.8T Big Turbo (it was stored from 2011). I would say that the hardware is OK and ready, it use to run OK, but not perfect, with the old base file (630cc file). The problem is that the old base file was with the vvt disconnected. Long story short, I change for a new base file and it runs like crap (and now I cant get back, I thought that I had the file that I was running saved, but that HDD died last year), the old file I put a bit more duty to the n75, lower the AFR and that would be.

Some specs:
MAF (Yes maf I don't have the intention to go mafless, I have read the functional structure of the ME7.5 and its an important input)
GT3071
630cc inj
Pauter rods
JE pistons
CTS exhaust manifold
Precision IC
iconel vales
AEM Meth inj
And a long list of extras

With the new one I have much higher AFR (with the same values than before), terrible idle and it pulls much less than before, exhaust gases are around 1200 - 1300F without meth inj, AFR @ WOT its around 12.5 (use to have it at 11.5), what I notice is that the turbo wakes up a bit earlier (vvt working now maybe?).

I have read almost every thing that I have found (VWVortex, Audizine, etc), and haven't found how to start tuning, is there a strategy or a step by step? Something like start with this table then to this and then to that one? Should I start with the 02 correction? the desired AFR? how do I get a smooth idle?

Sorry for all this questions, but for what I have read nothing makes sense... or the information is too specific or too general.

For anyone that could help me to start I will appreciate it

Thanks to all!

P.D Sorry for my bad English, I understand it better than I write it

Those are both useless sites.

See my sig.

Hello, (I send this like PM and I think I should post it here)

Thanks for your help and putting my post in the correct forum....the tuning wiki that you have at your signature...The order to follow is the same order you have written it?

In economy exist some kind of "law"...called "ceteris paribius"..means only changes to one variable at the time and try...this should apply to ECU tuning?

Right now it has a TT225 maf, Im going to a 4" MAF in the future, when changing I should make the following? (I should wait to start the tuning to have the new maf or I can start right now?)

TT225 diameter=2.75
New diameter=4.0

TT225 Area: 2.75x2.75 x pi = 23.75....
New Area: 4x4 x pi = 50.26...

Old / New = 0.47....

In maestro select OEM MAF and just to put the start value x 1.47... and the end value x 1.47

Thanks a lot!...and sorry for the noob questions...but for doing this you need some skills and knowledge

Please do not use a 4" MAF. If you need more than the 4.2 V8 MAF can handle, switch to a different flatform entirely, like the HPX :)

Always a good idea, unless you know the (simultaneous) changes you are making are unrelated.


This site is for full DIY, not maestro. Contact Maestro for tech support if you need help tuning with it.

Also, please don't PM me. They will be ignored. Read my sig again.

Yes don´t worry, that's why i'm asking here...
I want to know whats behind to understand it... no question at all about Maestro

Can I ask why?

It's been covered 10000 times, but sure.

A housing that large compromises low flow resolution for high flow capabilities. I personally like low flow resolution.

You are 100% right. I didn't mention it (sorry for that), I was thinking a map for track with the 4" and 2 bar and one for street with the TT225 and 1.2 bar...

For track use... high flow and low resolution or less flow and high resolution? would you still recommend the V8?

I have read that the HPX is quite complicated to scale...and its about USD 200 + shipping

This turbo is perfectly fine on a standard RS4/V8 MAF.

And unquantifiably more accurate.