Author Topic: Max boost pressure? (Read 21122 times)

awmw · « **on:** November 24, 2006, 03:52:45 pm »

What's the maximum boost pressure than can be safely run in an engine with standard compression?

hillfolk'r · « **Reply #1 on:** November 25, 2006, 01:56:19 am »

i let mine bury my 30 psi boost guage around to the zero stopper,so thats 40 psi

Benjamin · « **Reply #2 on:** November 25, 2006, 08:41:07 am »

25psi should be safe

40psi is not for a stock engine, also not for a normal garrett or kkk with long life (correct me if i'm wrong)

Greetz, Benjamin

hillfolk'r · « **Reply #3 on:** November 26, 2006, 11:45:48 pm »

yea its not the best for long life of turbos,but it sure runs good for a minute doesnt it??
i know mines a time bomb,those turbos dont live long like what i do to mine

but then again,he did wanna know max psi,he didnt say safely,lol
throw caution to the wind and keep it under 30 psi,itll be ok for a long while

Benjamin · « **Reply #4 on:** November 27, 2006, 08:10:58 am »

:mrgreen:

Greetz, Benjamin

awmw · « **Reply #5 on:** November 28, 2006, 03:48:19 am »

Those figures are higher than I thought, so at the moment, I think my standard turbo would be the limiting factor?

What's the higest safe

boost pressure from a standard VNT-15 turbo?

Benjamin · « **Reply #6 on:** November 28, 2006, 04:00:34 am »

for wich engine are we talking?

Greetz, Benjamin

awmw · « **Reply #7 on:** November 28, 2006, 04:35:54 am »

Sorry, I should have said.

It's a 1998 Audi 110Bhp, engine code AFN

hillfolk'r · « **Reply #8 on:** November 28, 2006, 11:21:25 am »

i dunno, im runnin a 98 tdi AHU engine
is that the 110hp version,and its still electronic i assume :lol:

RabbitGTDguy · « **Reply #9 on:** November 28, 2006, 11:45:18 am »

Quote from: awmw

Those figures are higher than I thought, so at the moment, I think my standard turbo would be the limiting factor?

What's the higest safe boost pressure from a standard VNT-15 turbo?

If your running a VNT-15 most the guys I've seen never run them above 18psi for an extended period of time. Usually, when upgrading nozzles, etc. you want to upgrade the turbo and move to what many have which were the VNT-17's and some are doing VNT 20's and better...

VNT-15 would be first applied on the ALH code TDI's, starting with the MKIV platform... I believe ANF is the same...with exception that it was a 110hp unit vs. the 90hp ALH . But that as difference between which side of the pond your on and the slight nozzle upgrade you get with it being a european model...

Joe

Benjamin · « **Reply #10 on:** November 28, 2006, 01:32:05 pm »

yeah, but vnt20 on a electronic tdi is not so good, they got so much lag...

Greetz, Benjamin

RabbitGTDguy · « **Reply #11 on:** November 28, 2006, 06:59:33 pm »

read over on the TDI club... with the right equipment and tuning they can make for a very nice unit. Some are running them and are very happy with the results. Just requires a bit more on the custom mapping side and a creative mind when it comes to other bits...

Joe

malone · « **Reply #12 on:** November 29, 2006, 02:25:21 pm »

For maximum boost in an ALH TDI, I'd probably stay within 30 PSI. To go any higher, headstuds should be added and compression should be lowered. However I'm going to set 32 PSI in a customer's VNT-20 next month because that's what he wants, despite warnings. Compression ratio will be stock. Reliability may be a hit or miss.

Quote

yeah, but vnt20 on a electronic tdi is not so good, they got so much lag...

Greetz, Benjamin

There is not so much lag with proper tuning. I've tuned two electronic VNT-20 TDIs and one of them responds very nicely, even with 17.5:1 compression ratio. The lag's not really that noticeable. The other vehicle still needs mechanical work before finishing the custom mapping, but for a taste of the power we unplugged the VNT vacuum and the VNT-20 responded decently. It hauled ass right from about 1,300 RPM. There was very minimal exhaust smoke too, with room for more fuel later.

There are many variations of VNT-20s and some may respond slower than others.

Normally most VNT-20s may feel a bit flat a few seconds above idle.. but after that - hang on! VNT-20s are much better than VNT-17s concerning EGT and HP efficiency.

The VNT-17 has the potential to make too much low-RPM torque (ridiculous in a FWD vehicle) but it still makes nicer HP in the top end than a VNT-15. The 17s are also a snap to install. It's also considered a more reliable turbo than the 15.

Depending on the VNT-20, the max recommended boost is approximately 28 PSI. That's sufficient for 200whp. Diesel Des dynoed 192whp uncorrected with 26 PSI in his 1.9L VNT-20/GT22v setup. He put down around 350ft-lbs torque but had the torque peak flattened because he broke drivetrain parts a few times within a week.

Max. reliable boost for a VNT-15 is 18 PSI. I have set a customer's VNT-15 to push 19.5 PSI once but that was only because he was swapping in a VNT-17 a week later... after the VNT-17 was installed a final VNT-17 chip was prepared with more boost (~22 PSI).

KermaTDI.com is now selling VNT-20 kits and he reported very minimal lag in his car. He believes it's worlds better than VNT-17 and I agree. The 17's still a nice low-cost solution though.

Benjamin · « **Reply #13 on:** November 29, 2006, 04:07:16 pm »

good news, a half year ago i readed very bad results from the better tuner local, thats why i said that...
@ RabbitGTDguy & Malone: tnx :wink:

Greetz, Benjamin

awmw · « **Reply #14 on:** November 29, 2006, 08:43:13 pm »

I've been trying to decide what nozzles to buy as a simple upgrade.

PP520 have been recommended as best for a standard engine and PP764 if I upgrade to a VNT-17.

I may get a VNT-17 in the future but I was thinking, could I run the PP764's now and if the smoke is too much, squeeze a bit more boost from the VNT-15?

Or should I be doing something completly different?