Garrett 38R 1.0 vs 1.15 dyno test

85_305 · Nov 23, 2012

Hey guys, I know I'm a bit late to the party, but it seems that the 1.15 housing makes less hp, less tq, and only has 2psi lower ebp.

I know that the 38r was tested, but I've been teeter tottering between getting a 1.0 housing on my OBS turbo or keeping the stock 1.15, and have heard (nearly) nothing but good things about the 1.0 on them. It seems that the 2psi in backpressure I might gain would be negligible, especially if it gives me 20+hp and 20+tq....

lincolnlocker · Nov 23, 2012

its been a while and i didnt read back through the thread but one thing that may be different is that there was no tuning changes... it was swapping one for the other to see any difference. so, might want to consider that some... i have no clue if tuning changes would still out weigh the cost to benefit ratio or not.

Lowdown89 · Nov 23, 2012

lincolnlocker said:
its been a while and i didnt read back through the thread but one thing that may be different is that there was no tuning changes... it was swapping one for the other to see any difference. so, might want to consider that some... i have no clue if tuning changes would still out weigh the cost to benefit ratio or not.

Actually bill did try changing the tuning some, he spent a good while trying to get that junk of a first batmowheel to work with each housing... First he tried no tuning changes and then with the wheel he tried all sorts of different things he probably made 20 or so Dyno pulls if not more. I have no idea how any of this would work with a OBS tho so I'm not any help there

lincolnlocker · Nov 23, 2012

oh ok. good to know!

85_305 · Nov 24, 2012

Well the reason everybody says to keep the 1.15 housing on the obs is because drive pressures are thru the roof with the 1.0. But it seems this dyno test had dispproved that?

lincolnlocker · Nov 24, 2012

85_305 said:
Well the reason everybody says to keep the 1.15 housing on the obs is because drive pressures are thru the roof with the 1.0. But it seems this dyno test had dispproved that?

two totally different turbos with different wheels.

85_305 · Nov 25, 2012

So you think that will change the outcome? My obs turbo is a 1.15 non-wg turbo with the wicked wheel stock. You think the 1.0 housing would impact that differently than the 38r tested in this thread?

Power Hungry · Nov 26, 2012

The stock OBS turbo and the 38r are two completely different turbos. A 1.0 A/R housing is going to respond entirely differently on the OBD turbo than it will on the 38r. A 1.0 housing on the OBS turbo will certainly gain you some boost and will provide considerably improved spooling characteristics, but the exhaust backpressures will be quite astronomical with anything larger than Stage 1 injectors, and even then they would be quite high.

One other thing to keep in mind is that the 1.0 housing on the 38r is WASTEGATED, so we can control drive pressure with a relatively simple adjustment. If you're using a non-W/G 1.0 housing, you kind of asking for trouble as you have zero control over your drive pressures.

As to the original testing, like Jason said, we made direct swap comparisons for the initial testing and then tried to adjust the files to see if we could tune-out the deficiencies. The results were that the 1.15 housing lost power and so did the BMW. The best combination so far was the 38r setup right out of the box.

I hope this makes sense.

85_305 · Nov 26, 2012

Ah so totally different than a non-wg 1.15 exhaust housing obs turbo. Thanks for the input man.

lincolnlocker · Nov 26, 2012

thanks fo the info bill... i didnt really know how to say it other then two totally different turbos.

sniper_101 · Nov 26, 2012

Lowdown/PHP, any plans to try the updated 38R Batmowheel?

Power Hungry · Nov 27, 2012

We have the new one on the bench and I'm just waiting for a new downpipe V-band clamp from Ford. The old one was on & off so many times it finally wore out. LOL Anyway, I'll be testing the new wheel this weekend or early next week.

4.0l sahara · Nov 27, 2012

I didn't even know they made a new version of that paper weight.

sniper_101 · Nov 27, 2012

Power Hungry said:
We have the new one on the bench and I'm just waiting for a new downpipe V-band clamp from Ford. The old one was on & off so many times it finally wore out. LOL Anyway, I'll be testing the new wheel this weekend or early next week.

Glad to hear, can't wait to see the results!

Also, expect a PM from me in a couple days with some questions about having my chip re-burned with your tunes, I miss that PHP quality tuning.