Shane's URD MRKlll++ supercharger Build

[shane881510]

U could make just as much boost or more on an ls as u could on 1gr. If the urd system used a crank mounted pulley like the trd did then u could get more boost. The Honda cars make about 18 to 20psi at redline because of such high rpms u could get the rotrex to the max impeller speed it will make boost.

 

[fishsticks]

Peak impeller speed on a C38 series is 90K RPM. Peak input shaft speed is 12K RPM. Doesn't matter how fast the motor will spin, the supercharger can only move so much air before inefficiency takes over or it comes apart.

A 6.0 LS theoretically inhales 50% more volume than a 1GR per crank revolution. Under boost, PSI is technically a measurement of air restriction, not power or volume. CFM out of the S/C is the same at a given RPM, so PSI will be lower on a larger displacement motor with a similar VE.

It should still make good peak power though. Shrug. I'd buy an -81 for $1500 if I thought I'd use it.

 

[shane881510]

I'd sell u an -81 for less than 1500$ if u want it. I could come down on the price.

 

[fishsticks]

I have nothing to put it on or I'd take you up on that.

 

[shane881510]

Just ordered a bottle of fluid and a filter the -92 will be on soon. Yay

 

[Torspd]

Is the Boost going to change, or only the flow?

 

[shane881510]

I'm not sure. It said that it flows 10% more throughtout the entire range. The -92 with a 80mm pulley makes about the same power as the -81 with 70mm pulley. So the -92 with 70mm pulley I don't know what it's gonna do. I wanted more tq and little bit more hp but mostly tq around about 400+ Ft lbs.

 

[Torspd]

How much longer until your parts arrive and you can install this blower?

 

[shane881510]

I got my oil and filter yesterday I'm gonna go ahead an install and wait on my intake elbow to fit to the blower.. Gadget told me not to use the 70mm pulley on it at first But idk. U can run a big turbo and it works pretty good. So I think I may go with the 70mm and do some testing and let Scott see some data and get me a tune for it. Like I said before I'm wanting more tq throughout the range I'm not pushing for maximum power. Just a good tune that I can drive everyday I needed and still race on the weekend. Like I do now. But more power than I have now. I just don't wanna max my fuel system out.

 

[Torspd]

Play it safe. Donthe datalogs with the 80 first. Since that blower puts out so much more air. See where it is and once you have that green light, go from there. It will be worth the short wait for proper validation. :top:

If you can, post up a datalog as well. It would be great to see.

 

[shane881510]

I may do that. Is 10% more air flow that much of a difference.

 

[shane881510]

I have the charger on and oil lines ran all filled up with oil. I went ahead and put the 70mm pulley on and I'm waiting on a elbow to adapt to my intake an it be ready for a new cal and be ready to drive.

 

[justin13703]

Man that c38-92 with a 70mm pulley is going to move an ass ton of air. Be careful. Like everyone else said I'd start with the 80mm and go from there. What's the huge rush about?

 

[shane881510]

I've run the beast a few miles now and I lowered my rev limit down to 6000 and it cut me down to 13psi of boost. But to be a bigger blower it's not that more powerful as I can tell.

 

[Torspd]

Plan to go back to 15 psi after the datalogs are sent?

 

[shane881510]

Idk I may keep it at 6000 just to be safe. I feel better about shifting at 6000 than 6400. But I'm waiting on Scott to tell me how my data logs was and if I need a retune. As I done my data logs I watched my afr and both seemed to stay in the good all the way to redline. But I can't read them data logs to good. I was hoping for a big improvement with this -92 blower but I can't tell all the much it may just be me tho.

 

[Torspd]

The things to look for in the datalog, to compare power from the old blower's datalogs to the new. Load, Maf g/s (grams of air per second).

Those two are effectively torque and HP. Load = torque.

 

[shane881510]

Oo he said that my last data log was good. The afr was good the adaptive was within 5% and my load was 200% and maf g/s was at 499.

 

[Torspd]

By that, it means that your timing and knock prevention are both still good. :top:

Turn the rpm boost back up!

 

[Torspd]

The only other way that I can see you gaining a lot more torque, is by installing some cams.