What to do ?

[full tilt viper]

Can I push it a bit more ? Nytro XTX Stage 1 with inter cooler and cold air kit ( moved the intake vertically out and up out of the hood . No fuel pump or head shim.Running 1" 1/8 ice attack with 224 studs as well. Had it geared 22x39 just changed it back to stock 21x39. It should hook like hell now on the bottom. Been running 27bx28t for a couple of years now. It runs 5.5-6.2 depending on temp and rpm. AFR's are really good and its getting lots of fuel. I have a 29b sitting around. I tested it last year and it showed solid 7 pushing 8.2.AFR's were....ok. A few years back on my other xtx I ran 29bx25t no head shim on pump gas, it did have the fuel pump upgrade. It made 9-10 and lived for 2 years before it dedonated and it probably shouldn't have lived that long. If it would live at 25tx29b would it not be ok going 29bx28t it a huge difference. Boost is so damn addictive !

 

[MrSled]

Can I push it a bit more ? Nytro XTX Stage 1 with inter cooler and cold air kit ( moved the intake vertically out and up out of the hood . No fuel pump or head shim.Running 1" 1/8 ice attack with 224 studs as well. Had it geared 22x39 just changed it back to stock 21x39. It should hook like hell now on the bottom. Been running 27bx28t for a couple of years now. It runs 5.5-6.2 depending on temp and rpm. AFR's are really good and its getting lots of fuel. I have a 29b sitting around. I tested it last year and it showed solid 7 pushing 8.2.AFR's were....ok. A few years back on my other xtx I ran 29bx25t no head shim on pump gas, it did have the fuel pump upgrade. It made 9-10 and lived for 2 years before it dedonated and it probably shouldn't have lived that long. If it would live at 25tx29b would it not be ok going 29bx28t it a huge difference. Boost is so damn addictive !

You can easily run 7 lbs on a nytro with good fuel.

 

[full tilt viper]

Stock fuel pump ? Anyone running 29bx28t ?

 

[MrSled]

Stock fuel pump ? Anyone running 29bx28t ?

From what I understood, yes. Viper with a cat style pump can really run close to 6.5 lbs

 

[full tilt viper]

Same pump ?

 

[MrSled]

Same pump ?

Yes, Talking to Allen when you go above 7lbs on the Viper you need more fuel and the Nytro didnt have as much of a problem as the Vipers did.

 

[Big_Phil]

Im not 100% sure with the supercharger kit.

But in my experience with turbos, 5 psi and thats it with the stock fuel pump and injectors. Anything higher, and on a long pull the AFR starts getting high. Can do 7 psi for short bursts or racing, but I wouldnt leave it there all the time.

 

[Srxspec]

Stock fuel pump ? Anyone running 29bx28t ?

I'm going off of memory here, but I don't think you can get a 29/28 to fit with the belt, but I don't remember for sure. I think you have to stay between 54 to 56 teeth total (28+28 = 56, 29 + 25 = 54) for the belt length to work.

On a supercharger you can run the boost up to 8-8.5 lbs (depending slightly on elevation) and still be fine on the stock fuel pump on the FX Nytro. The supercharger simply doesn't make as much horsepower due to the fact that it takes 4% of your power to drive it, compared to a turbo.

 

[full tilt viper]

The belt does work with 29bx28t . It's on the tight side but it works. Watched gauges closely today running the 29bx28t. At 9000 RPM it's making a solid 8lbs. AFR's at WOT were creeping up quickly into mid 14's. Kept it to short bursts but I've got to get the boost down. -10 hard pack groomed conditions. Still waiting on my 28b to arrive which I think will be 6.5-7. that's my target and I hope I can give it enough fuel . Running 27bx28t ( 5.2-6 lbs )I have no trouble giving it lots of fuel