Ulmer Turbo, Nytro Max boost??

[quadtrac]

I have a 08 Nytro with a Ulmer stage 1 turbo kit on it. The turbo is a garret #GT2554R and I have the adjustable boost controller on the sled to. We are going to the big horns on the 31st and was wondering what the max boost pressure I could run on this sled? Elevation will be mostly around 9k, maybe some places higher. I was planning on using 50/50 pump and 100LL avgas in the sled, but if I can run more boost I will run just straight 100ll! What do you guys think is safe??

 

[bottlerocket]

I think your fuel system will limit the boost output. Stage one is

 

[quadtrac]

So how much boost can the stock fuel pump handle at high elevation?

 

[bottlerocket]

From the website:
Stage 1: The Stage 1 kit is aimed for a nice overall increase in horsepower that is trail friendly. This kit is aimed at those trail riders looking for more horsepower, but still having stock reliability. At 180 hp this will run with or ahead of pretty much any other trail sled out there. It will get good fuel mileage. This kit is limited to 6 lbs maximum boost on 91 octane fuel. Race fuel will not allow you to run a higher boost because the stock fuel pump is not adequate above 6 lbs boost. This is the gas & go turbo setup for 99% of trail riders! This kit is intended to be installed on a 100% stock motor!

 

[dirk_03]

Boost

You could run up to 10 lbs on the stock motor on pump gas if your fuel system could foot the bill. I do not believe that it can though. If I was you I would get a NM fuel controller. Would be the cats meow and then you would only be limited by the size of the turbo and the fuel you run.

I think you will be pretty happy with 180 true hp at elevation.

 

[towerrigger]

You can run up to 10lb with the stock fuel system. Depending on elevation. You may want to get a map for the stage 2 from Ulmer.

I run anywhere between 8-10 on the stage 2. Stock engine, stock fuel system. Premium fuel all at elevation.

 

[mbarryracing]

You can run up to 10lb with the stock fuel system. Depending on elevation.

bottlerocket is correct. The stock fuel system on the Nytro starts petering out at around 6 lbs boost even at 1600 foot elevation, so means it's worse at sea level.
This is undeniably evident on the AFR O2 sensor going lean, supported by the data on the dyno sheets from FPP's stage1 Nytro testing (just bolted on stock motor) at Dynotech Research (900 foot elevation) that I posted on the following thread.
http://www.ty4stroke.com/viewtopic.php?t=87839&start=0
You can see the AFR starts going lean, and I believe the injectors were at 100%. Ulmers stage1 is also on the stock fuel system, so that AFR data should apply to either.
I agree with bottlerocket, no way does a bone stock fuel system have the capacity to support 10 lbs, atleast at lower elevations and not even on race fuel.
However, i don't have any data for higher elevations.
What elevation is your 10lb information for? I thought I read somewhere that even the Yamaha turbo kits from PUSH or MPI are only rated for 7-8 lbs at +6000ft ?

Also note worthy that stage 2's do NOT utilize the bone stock fuel system, maybe for this reason.

 

[Srxspec]

Stage 1 fuel & boost specs.

Sea level to 6,000 feet on 91 or 93 octane (premium) 5-6 lbs.

6,000 feet to 8,000 feet on 91 or 93 octane (premium) 8 lbs.

8,000 feet or higher on 91 or 93 octane (premium) 10 lbs boost (the turbo will make more, but at the elevation on that turbo you're just going to create more heat and not any actual higher horsepower at a higher boost than 10 lbs).

It never hurts to add a little octane booster (like Torco Race Fuel concentrate) or mix in some higher test gas to make sure you've got a true octane level.

 

[towerrigger]

You can run up to 10lb with the stock fuel system. Depending on elevation.

Also note worthy that stage 2's do NOT utilize the bone stock fuel system, maybe for this reason.

I am running a Stage 2 HE Ulmer kit with no changes to the fuel system. The non HE stage 2 kit adds a fuel pump.

 

[mbarryracing]

Well, I did admit I wasn't familiar with higher elevations. i knew it effected the amount of boost but had no idea it affected it that much. Thanks for posting the information Allan.
What kind of air fuel ratio's do you see at 10 lbs on the stock fuel system above 8000 feet? Still pretty safe, or is it starting to get border line?