Repercussions from simply fitting a larger turbo?

ruds · April 3rd, 2012, 03:04

Hey guys,

I have a 130bhp variant of the TDI engine fitted to my T5. There is a 174bhp version and I have a brand new Garrett VNT turbo from the 174. I am told it is a straight swap.

I have had my 130 remapped to ~160bhp but although it has made a big difference there is a large flat spot in the power band from 2000-3000rpm. I don't know what causes this?

Other than that issues I have no other problems that I know of.

What would happen if I simply fit the 174 turbo and do nothing else?

m1ketdi · April 3rd, 2012, 12:19

It would be a waste of the turbo, get a new custom map to go with it. You might need bigger injectors too though...

Ed's TDI · April 3rd, 2012, 23:22

Quote:

Originally Posted by ruds

What would happen if I simply fit the 174 turbo and do nothing else?

Without more specific info on the turbo size/model, I'd guess te result would be a laggier response in spool up down low and possibly an even more noticeable "flat spot" . I agree with m1ketdi that you would likely need to get bigger injectors to supply more fuel, and you'd definitely need a remap for all the new hardware, otherwise why even bother. Just my 2 cents' worth.

faboka · April 4th, 2012, 07:34

If your current tune overfuels then fitting the larger turbo might result in this unburnt fuel now being used making more power.

Personally I'd get it mapped to suit the new turbo. What's the details of the turbo?

ruds · April 4th, 2012, 08:22

Thank you for your replies guys!

The reason I asked was incase there was no downside to fitting it now and having it remapped to take into account the turbo upgrade within the next month or two. I had wondered if the flat spot in the tune at the moment was due to a lack of airflow but I don't see any smoke at WOT so maybe it's something else.

I do not know the exact specs for the turbo in there now but the replacement says the following:

Garrett GTB1752
M68 A/R .74 (hot side)
M53 .45 9 (cold side)

Some guys have sent them away to be upgraded but I'm not sure what I would ask for...

The company that I will have remap it have said the injectors have been good so far up to 220bhp and even at that are still not at their limit so hopefully I can keep the stock injectors for now.