justinp20012500

Simple... Just changing the correction factor can do that.

David Dunbar and myself were involved in a conversation a little while ago about the Dynojet 248c and the Mustang M1750.

I was only at 384 RWHP a year and a half ago. I laid down 384 RWHP on a M1750 dyno and a week later I ran a 14.081 @ 97.75 MPH (2.227 60').

David was simply amazed that the truck could go that fast with such a slow 60' time with only having 384 RWHP. (No correction factor was used when I dynoed, and I am @ 4600' elev.)

You can easily find out your HP the old fashion way. Its just a simple physics formula, just take the info from your quater mile and apply it.

"It takes xxx amount of power to move a load that is xxxx heavy at xx miles per hour and xx et"

One is inertia, and the other is a load dyno.

One dyno measures how fast you can spin the drum over a given amount of time, and the other puts a load through the rollers to the vehicles drive train to measure applied power.

Dynojet does sell different weight rollers. The heavier ones really help trucks will large single turbos build full boost.


Justin

RowJ

Every time I have applied the drag racing formula you speak of, based on 1/4 mile speeds, I have gotten about 10% to 15% higher hp figure than I get on a dyno??
RJ

justinp20012500

Did you calculate the percentage of slip through the drivetrain?

RowJ

Justin,
Don't know what it is...or how to do it. I assumed the CD given me buy a NHRA racer did all that was needed? I just punched in my weight, altitude, wind, temp and 1/4 mile speed.
RJ

oscaroc

I have been reading HTT's web site and i think I understand turbos a liitle more.

Correct me if I am wrong. I you want faster spooling(less lag) you go with a smaller turbine housing, but in turn you sacrifice top end and higher boost numbers. If you do a larger turbine housing you get slower spool up but higher boost numbers and greater top end power. Where does lowering your EGT's fall in to this?

When changing your turbine housing do you also change the actual turbine too.

The compressor wheel and housing is still confusing to me! could someone explain that part to me?

RowJ

Lowering your EGT's comes in by using a larger turbo that moves more air.

You don't normally change turbine blades...they and precisely balanced on their shaft at 100,000+ rpm. Not something we want to try in the garage.

I would not get too wrapped up in the compressor side of things. it's pretty much "along for the ride" due to it's being directly tied to the shaft of the turbine wheel.

Mfg's can play with the # of blades on the compressor wheel to accomplish a difference.....this is how the B-1's do it. They may play with the angle of the blades also...not sure.

All B-1's have the same compressor side...but with different #'s of blades. This is done to match the different size turbine housings and the # of turbine blades.
Example:
KSB1-2 comes with 7 double compressor blades, 11 turbine blades...and a -2, or more constricted turbine housing (A/R ratio). Designed for up to 425 hp.
KSB-1 comes with 6 double compressor blades, 10 turbine blades...and a -1, or more open turbine housing. Designed for up to 475 hp.

If anyone knows # of blades on B1-2 and Full B-1, I would love to know!

HTT is changing turbine housing sizes (A/R ratios) AND compressor inducer sizes to get varying degrees of when turbo rpm kicks in to compress cool air. If I understood what Paul told me..they are not playing with #'s of blades.

Hope this helps!
RJ