rr2.60 dyno results are in

wuplash

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i was hoping for more rwhp but oh well the torque is nice.the temp was 83.76 degrees in the shop and the barometer was sitting at 29.51 in-hg.i managed to lay down 455 rwhp 499 rwtq after a 40 min cooldown from driving 110 miles to them numbers are sae.i really like my a/f ratio it's much better than when i had the rr2.75 and amazon cai,with that setup i was at 12.3 now with the rr2.60 and jlt cai my a/f is flat like kansas and at 6,200 rpms the a/f is 11.9.so i ended up gaining 11 rwtq and losing 2.6 rwhp at peak.my next set of mods will be to make the engine and eaton more efficient because looking at my dyno graph it is begging to breath deeper,a nice set of mid length headers and ported eaton should help the ole gal out some:rockon:
 

Juiced-03

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Hmmm,, not bad I guess. I think you pushed it a bit too far, but hey if it feels quick that's all that matters (until the Eaton seizes lol)!

Does the belt slip at all or does it hold all the way to redline?
 

wuplash

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Originally posted by Juiced-03
Hmmm,, not bad I guess. I think you pushed it a bit too far, but hey if it feels quick that's all that matters (until the Eaton seizes lol)!

Does the belt slip at all or does it hold all the way to redline?

the 2.60 does exactly what my 2.75 did hold max boost thru 5,100 rpms then starts to gradually drop off.the 2.60 shows 15lbs thru 5,100 rpms then drops to just under 13 by 6,200 rpms.i don't have any belt slip or spark blowout.the under curve numbers show better results on my 2.60 vs the 2.75 but not anything to write home about as it was in a very narrow rpm band.to be honest it really feels like i picked up hp but i won't know for sure till i run one of my buddys again to gauge any difference,i can really feel the torque gain holy cow.
 

unit213

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I still don't understand the 2.60 upper as opposed to a upper/lower combo.
 

JKD COBRA

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good job wuplash :thumbsup: Your torque is just awsome.

Do you think you can post the graph? I can host it for you if you need it.
 
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Originally posted by unit213
I still don't understand the 2.60 upper as opposed to a upper/lower combo.

Changing the lower will speed up the altanator and poss kill it faster where as the upper only speeds up the blower!:beer:
 

trey193

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And the upper pulley and milling of the snout is a helluva lot cheaper and easier to install than a lower. Good numbers Jim I am surprised U lost power just looks like 14lbs is all these blowers want. U need to go run Josh and see if there is any difference!
 

IronTerp

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Originally posted by wuplash
the under curve numbers show better results on my 2.60 vs the 2.75 but not anything to write home about as it was in a very narrow rpm band.to be honest it really feels like i picked up hp but i won't know for sure till i run one of my buddys again to gauge any difference,i can really feel the torque gain holy cow.
It's the area under the curve that would vindicate going 2.60.......Your peak torque is up, but how does the rest of the curve look like for torque, especially at middle rpm ranges?
 

wuplash

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Originally posted by trey193
And the upper pulley and milling of the snout is a helluva lot cheaper and easier to install than a lower. Good numbers Jim I am surprised U lost power just looks like 14lbs is all these blowers want. U need to go run Josh and see if there is any difference!

yea josh is going down if he wants to run:-D

i fixed my intercooler tube while ago with that stuff i was telling you about and i bet that sucker won't be coming out again:rockon:
 

wuplash

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for those who would like to compare my rr2.60 dyno vs my rr2.75 can do so here http://img72.photobucket.com/albums/v219/wuplash/488rwtq_dyno.jpg

i was dead tired yesterday when i got back home from the dyno so i did not mention it then but i will now since some sleep has revised my thoughts on yesterday.when i got to the dyno i did let the cobra cool off for 40 min and the first run yielded 446rwhp 494rwtq which made me a little upset to say the least,but that was not all.as you know i installed a new blower snout which was lathed down for the 2.60 pulley but to get the factory one off you need to play with that intercooler tube right in front of the bottom bolt,we remembered people said to just tap it down a little for the needed clearance to get that bolt out,well mine tapped down some but it also made it lose when we put it back in after installing the snout,i had even made several hard passes on the street and that tube was still ok so i thought all was well.but on the first pull that tube came out and drained out all my intercooler fluid from the reservoir tank so i'am certain my blower was not being cooled properly hence the low rwhp reading on the first pull.well after we noticed what took place we placed the tube back in clamped the hose back on and refilled the reservoir tank and made another pull 15-20 min after the first one and it then layed down 455rwhp 499rwtq which was an increase of 9rwhp and 5rwtq on an already warm motor with nothing else being done to the car.so needless to say i will be going back to re-dyno again very soon as i really believe i got robbed of what the cobra is really making power wise.yes i do have the intercooler tube fixed to where it won't come out again i used some magnum steel around the base and it's not going anywhere now.stay tuned
 
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trey193

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I hear ya Jim if that fluid was gone and not cooling the blower properly U def. are leaving some power on the table. Maybe I can roll with ya nextime!
 

wuplash

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Originally posted by trey193
I hear ya Jim if that fluid was gone and not cooling the blower properly U def. are leaving some power on the table. Maybe I can roll with ya nextime!

yea you will have to stick your cobra on the dyno and make it beg for mercy :-D

mine will only get it warm for ya:burnout:
 

betiwin

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Not to hijack you thread and no disrespect to you it is your car and you sound very happy, but what I do not understand is all this talk of torque being higher with a smaller pulley. I know that the peak trq. is higher, but at 2500-3700rpm. I know that when i shift my car at 6,300-6,500 rpm it drops to 4,800-5,000 rpm which is were you want horespower to carry you through the rest of the rev range correct? My 2.90 pulley made 462hp and 480 trq, but at much less blower speed. I just wonder if the trq is that much different from 4,800 to redline, but good dyno run I am sure that thing is a screamer.:beer:
 

wuplash

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Originally posted by betiwin
Not to hijack you thread and no disrespect to you it is your car and you sound very happy, but what I do not understand is all this talk of torque being higher with a smaller pulley. I know that the peak trq. is higher, but at 2500-3700rpm. I know that when i shift my car at 6,300-6,500 rpm it drops to 4,800-5,000 rpm which is were you want horespower to carry you through the rest of the rev range correct? My 2.90 pulley made 462hp and 480 trq, but at much less blower speed. I just wonder if the trq is that much different from 4,800 to redline, but good dyno run I am sure that thing is a screamer.:beer:

no disrespect taken:thumbsup:

with a smaller upper pulley the blower will spin up quicker and have a higher peak rpm vs a bigger pulley,this in turn will give you more torque down low as the eaton can benefit from this,but once you get it up to 5,000+ rpms the hp gains of running a small upper pulley starts to diminish due to the blower is now past it's efficiency design and more heat is being made.while this is true and peak hp will not be to much different than from a pulley of just a little bigger size,one needs to look at the whole graph to see the various hp vs rpm differences to see the gains one can obtain from a smaller upper pulley.granted my 2.60 did not show much gain hp wise vs my 2.75 but like i posted earlier about the intercooler tube coming out and hosing the coolant out onto the motor and possibly my belt as well i'am certain it cost me some power on that cool engine pull and the pcm was taking timing out due to the blower not being cooled with coolant,the dyno operator told me on the first pull the cobra did not feel good from 5,000 rpms up to 6,200 rpm shutdown but on the 2nd pull with the tube staying in place he said it felt great and the dyno showed it with a 9rwhp gain,so i'am certain timing was being taken out on that first pull.from what i see so far my torque from 4,800 on up is not much different vs my 2.75 pulley but the torque is much better from 2,600-3,700 rpms which is usefull on launch from first gear or a street 2nd gear roll.btw nice numbers from your 2.90 pulley:beer: are those numbers sae or std??
 
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Fresh Cobra

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CONGRATS on your overall numbers!!! I guess I'm one of the 'few' lower pullie runners out there, but, to each their own. Again...Congrats!!!

~ Fresh :burnout:
 

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