Have a look at the quote below, 2.7hp for each lb lost from the crank?? that would mean by fitting the kit from Smithy you should see over 27HP increase at the crank?? Any tech heads capable of elaborating on this a big? in a real world situation do you really see increases like this?

 

Cheers

 

Dave

 

 

 

From http://www.dragracing.com/product.asp?prodid=2333&catid=22

 

 

Unorthodox Racing aluminum crank pulleys on average can provide gains of 5 to 14 HP and 4 to 12 lbs.-ft. on normally aspirated engines and 8 to 18 HP and 8 to 14 lbs.-ft. on forced induction engines. Higher gains are possible. For example, a Nissan 300ZX twin-turbo saw gains as high as 37 HP and 45 lbs-ft. on the dyno just by replacing the stock crank pulley with our Ultra S series lightened underdrive crank pulley.

 

Power gains are obtained through weight loss on all our pulleys. An average of 2.7 HP is gained from every pound lost off the crank shaft. 85% of our gains are from weight loss. In our Ultra S models, we introduce underdriving for additional power gains.

I get emails every day about a part of my anatomy that also would grow greatly by using certain products. ;) Never thought to hang an underdrive pulley on it tho but that might actually work for it.

 

An underdrive pulley'll never deliver 37bhp extra unless maybe it revs to 9000rpm.

 

Look for the evidence from real users. The best I saw on a dyno chart was 12bhp in various parts of the rev range and two thirds of sod all at the bottom end. Some people waste more than 12bhp with a big Hi Fi. You get more power variation between cool weather and hot weather.

I've had mine fitted since my last dyno at Thor and I'm back there in 2 weeks. I'll let you know what the results are...

 

Steve :)

I've had mine fitted since my last dyno at Thor and I'm back there in 2 weeks. I'll let you know what the results are...

 

Steve :)

 

Results showed an extra 14rwhp with the SGP pulley.

 

Previous run:

291.2 rwhp

308.3 ft/lb

 

With SGP:

304.9 rwhp

313.5 ft/lb

 

http://www.300zx.co.uk/forums/showthread.php?t=38220

 

Pretty pleased with the results..

 

CheerZ

 

Steve :)

Nice. Notice you had a different chip fitted also, could'nt that of contributed to some of that increase too ?

On a related matter, if you guys are interested in ATI crank dampers there's an interesting discussion here

Higher than expected BHP gains could simply be due to the timing not being set correctly in the first place, fit new pulley, set timing correctly, hey presto 37bhp gain ;)

Nice. Notice you had a different chip fitted also, could'nt that of contributed to some of that increase too ?

 

Possibly but I wasn't really expecting any BHP increase from the chip, just improved fuelling... Could the chip (MINES) have made a difference as well?

 

Steve :)

Higher than expected BHP gains could simply be due to the timing not being set correctly in the first place, fit new pulley, set timing correctly, hey presto 37bhp gain ;)

 

I don't think the timing was changed in any way Andy - just a straight swap of the pulley and belts. Would this have any effect on the timing?

 

CheerZ

 

Steve

The chip could use different timing. Also changing the fuelling will affect your power.

 

mind you, I still think the UD pulley makes quite a difference, surprised me when I moved it over to the SWB, even at 9psi.