OBX Power Pulley Kit sr20de

frank said:
and these 6-12 hp claims are bollox, a 65amp alternator consumes about 1hp (65a x 12v= 780watts = 1hp) and thats if the battery is flat and full revs (if the battery is at normal voltage then the regulator in the alt drops it to a trickle charge)
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Might I add that a car alternator is only 50% efficient. And what you calculated is the power of the alternator, not the motor input. Just for info :P
 
If your maths are correct.. and the reduction in load due to reducing weight of these pullies is minimul.. Where are these proven figures coming from?..

Your saying the p/s is PROBABLY 2hp. and a 10th when closed
Your saying is the w/p draws about 1/2bhp at full chat?
The alternator is 1hp..

Not having a go Frank but are these facts?

..or probably facts?..

Also its all relative to the engine.. is a micra engine running P/s going to have same losses as a 150bhp Fwd engine..

or are they a ratio, making the losses relative to the initial power output anyway..?.

Even so.. I think your assumptions are out by quite bit.
 
kristian said:
Not having a go Frank but are these facts?

..or probably facts?..
.
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i cant qualify the probably facts kristian no, but an electric waterpump will be rated 1/2 a hp max i,m sure
a 65a alternator can only output 65 amps max = 780 watts = 1 hp ,fact
i have a 12v power steering pump and its rated at about 1/2 a hp
a pollyvee belt will start to slip when you transmit about 2 or 3 hp (personally tested) and will snap at around 8hp (gokart tinkering lol) they,ll stand around 500kg if you want to use one on your engine hoist :eek:
and the "losses" figures are constant aint they (if you have 50hp 200hp or whatever)

frank
 
frank said:
i cant qualify the probably facts kristian no, but an electric waterpump will be rated 1/2 a hp max i,m sure
a 65a alternator can only output 65 amps max = 780 watts = 1 hp ,fact
i have a 12v power steering pump and its rated at about 1/2 a hp
a pollyvee belt will start to slip when you transmit about 2 or 3 hp (personally tested) and will snap at around 8hp (gokart tinkering lol) they,ll stand around 500kg if you want to use one on your engine hoist :eek:
and the "losses" figures are constant aint they (if you have 50hp 200hp or whatever)

frank
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I understand your thinking Franks, and it makes complete sense.. I THINK the drain is a ratio, and I think its expanential.

So more like 3% of engine work, rather than a set 5bhp for all ancilleries.
 
Kristian thank you for the work and effort. its been tested that with the UR pullies at least, the crank & wp is said to be worth 4hp - 6hp and the other 2 another 1hp - 2hp at best.
 
Thanks david,

Im trying to give a little accurate information.. as the misconceptions on things like this are huge..

PLUS.. it might reveal a huge gain to be had by removing water pump / P-S

Anyone have any close pictures of the other pullies for comparison?.. just to be sure they aren't the same?..
 
kristian said:
I understand your thinking Franks, and it makes complete sense.. I THINK the drain is a ratio, and I think its expanential.

So more like 3% of engine work, rather than a set 5bhp for all ancilleries.
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we,ll have to disagree then eh :P
mine,s got the waterpump idler removed, and a very slack belt to cut down on belt/friction losses
http://img691.imageshack.us/img691/677/belty.jpg
and the 2 x bigger alt pulley (more contact allows a slacker belt also eh)
and a diy 3.5kg flywheel
so i dont think i,ll be buying any underdrive kit lol :)

frank
 
frank said:
we,ll have to disagree then eh :P
mine,s got the waterpump idler removed, and a very slack belt to cut down on belt/friction losses
http://img691.imageshack.us/img691/677/belty.jpg
and the 2 x bigger alt pulley (more contact allows a slacker belt also eh)
and a diy 3.5kg flywheel
so i dont think i,ll be buying any underdrive kit lol :)

frank
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I wouldn't buy an underdrive kit for a 56 / 76 bhp engine either bud.. Nor would I port and polish the head... or even lighten the Fly.. the gains are just too small.

I dont think the idler pully is even worth removing either, a Slack belt is a bit of a Risk IMO

However on the SR.. IF its possibly to get 8bhp from these then that could equate to around 16 on my 300+ motor.. nudging 350bhp I COULD squeeze another 20bhp. A few more Clever changes and I could be first in country to approach 400bhp with standard DE block and head. engine..

This I think is worth a little time and effort to find out.

( currently trawling the net to find some previous research done )


EDIT..

It seems the weight differences are the REAL Benefit.. underdriving Can achieve up to 25/20% of the gain to be had from fitting the pullies.. So back to our weights and maths it seems..
 
kristian said:
I wouldn't buy an underdrive kit for a 56 / 76 bhp engine either bud.. Nor would I port and polish the head... or even lighten the Fly.. the gains are just too small.

I dont think the idler pully is even worth removing either, a Slack belt is a bit of a Risk IMO

However on the SR.. IF its possibly to get 8bhp from these then that could equate to around 16 on my 300+ motor.. nudging 350bhp I COULD squeeze another 20bhp. A few more Clever changes and I could be first in country to approach 400bhp with standard DE block and head. engine..
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those belts ran ok at mallory park eh ;)
and how can the losses go up when you have more power kristian ? transmission/gearbox losses do obviously (increased friction)
but a certain p/s pump/alternator/waterpump have the same draw whatever engine (ie a 65a alternator will draw the same/output the same 1 or 2 hp if its fitted to a CG10 or SR20det)

frank
 
Im keeping OE pulleys on my VE, although ive never had any problems with my UR set, I dont like the idea of underdriving the WP.... or spinning the crank upto 8500rpm without the balance of crank and pulley, the 4cw might be good but everything has its limits.
 
The AMOUNT of conflicting information on this subject.

It transpires the SR Crank pully isn't harmonically balanced.. Im going to rip apart a spare anyway..


Concerning the W/P.. The flow rate as far as I can make out 'max's out' above 4.5k and using solely the Crank pulley lifts this limit to around 5k... Actual pressure increases, but flow rate flatlines, or even decreases..

I might yet change this deduction after some more research.

I think the UR pullies are fine to use Kurt..

My Waterpump pulley is Over driven, and this pretty much cancels out the Under drive of the crank pulley..
 
kristian said:
I wouldn't buy an underdrive kit for a 56 / 76 bhp engine either bud.. Nor would I port and polish the head... or even lighten the Fly.. the gains are just too small.

I dont think the idler pully is even worth removing either, a Slack belt is a bit of a Risk IMO

However on the SR.. IF its possibly to get 8bhp from these then that could equate to around 16 on my 300+ motor.. nudging 350bhp I COULD squeeze another 20bhp. A few more Clever changes and I could be first in country to approach 400bhp with standard DE block and head. engine..
Click to expand...

i would turn that on its head and say that the 1 or 2 hp gains (or 12hp if you want lol) would have more affect on a 50hp engine (2 to 4 %) and would be negligable/irrelavant to a 350hp engine
in the same way as a 4kg lighter flywheel would have far more affect to the smaller engine :)

frank
 
frank said:
i would turn that on its head and say that the 1 or 2 hp gains (or 12hp if you want lol) would have more affect on a 50hp engine (2 to 4 %) and would be negligable/irrelavant to a 350hp engine
in the same way as a 4kg lighter flywheel would have far more affect to the smaller engine :)

frank
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This is our disagreement pal..

I think its the opposite.. I think a 4kg fly on a smaller engine having a bigger effect is crazy.

Ive found 'evidence and date' onine but theres just as much against them.. usually about the non existant harmonic balacing.. rather than a 'quieting' issue...

Ill have a pretty conclusive answer over the next couple of days.
 
Rather then starting a new thread

Has anyone heard about these.. stumbled across them whilst looking for UR pulleys

http://www.cdfracing.co.uk/product_info.php?products_id=209&osCsid=3c7f654f04c7e40d44cb0da0af7b29a1

With postage & Tax's will work out about the same price as the UK equivalent

Kit includes Crank/Waterpump & Alternator... you can get them to do you a powersteering pulley also :) & Possibly A/C but havent decided yet if im keeping the A/C

Whereas the UR Pulley set includes Crank & Waterpump only

Ive emailed them to enquire if they are underdriven/overdriven & weight's of them as there isnt much information about them... Will report back with more info


UR pulley set for reference

http://www.unorthodoxracing.com/Itemdetail.aspx?PartID=041001702&Year=1999&Make=30&Model=218
 
Ive bought my Unorthodox pulleys from the US all 4 for the equivalent of £110.

somebody bought a set of these think it was Andys but his crank pulley fouled on the oil cover, Rowdy is running one of their alternator pulleys

The aircon pulley is quite different from any of the others
 
Thats mint Sam, Im struggling to even find stage 2/4 Peice UR kits for sale?!

And re Andy's ohh would of thought they had pulley manufactured with a collar pressed over the inside of the pulley.. mabey so but not correctly. A line of enquiry none the less.. being a proper firm. If one replaced the oil seal when fitting and a problem occurred would be in reason to send the crank pulley back to them for a refund as it failed to deliver.

UR themselfs only list a 2 Peice Crank/WP set too, ill be dammed if its discontinued.. cause that leaves me with Gspec there damn expensive or try

JGY set


http://www.jgycustoms.com/serg20/underhood.htm
 
Yeah i`d stear clear of the CDF crank pullys. The ALT pully is good though, because at the time UR weren`t making them anymore. Dont know if that has changed?
 
Solution, buy the UR kit Crank/WP there supposed to be the best 'Peice of mind factor' and get rid of the waterpump cavitation at higher rpm's

Then contact CDF to buy:

Alternator
Powersteering
Possibly A/C will have too inquire if its possible as Sam suggests something in the midst

Or just buy the JGY kit, looks identicle in design to the UR kit probably just a copy tbh

There's so many cool bits for sale on the JGY site, its like Christmas all at once :ninja:
 
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