So I have a whipple 2.3 w/ a 3.5 upper and a 4lb lower. I hit 17 lbs at sea level and also at 1200' on the dyno on cold day. I live at 4700 and it's like 30 degrees outside. I just got done making a few passes on my local deserted hwy. Using the nexus gauges I recorded the runs and only made a max of 15 lbs in 2nd gear 15.5 in 3rd and 16 in 4th. How much power do you think I'm leaving on the table missing out on the last couple lbs of boost. Also w/ the temps outside now that's probably the coolest it's going to get, do you think if I ran a smaller pulley that would add 2 more lbs of boost that I'd be okay. I'm limited to 91 craptane and don't want to push it to far.
down a couple lbs
- Thread starter jophis37
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That sounds about right for an elevation of 4700ft. You are generally going to loose boost when you travel to places located in higher altitudes. The air is thinner, so there is less air per rotation running through the compressor. You would probably be fine adding two more lbs of boost, just make sure that your tune is spot on, and if you make a trip to lower elevations make sure that you make all of the proper adjustments.
-Jeff
-Jeff
-Jeff
-Jeff
HISSMAN said:
I'm worried that if I add another two lbs of boost and actaually see 17 here at 4700, that I'll end up seeing 18 at 3300. Any idea how much difference ther is between 4700 and 3300'? I'm sure that when the temps get up to 80 90 degrees that I'll see even less boost. I checked into what the temps were last night and they were between 31-34 degrees.
HISSMAN said:
Thanks, I just sent him a pm. I'm thinking that I'm just gonna hook up an oxygen tank to the filter. The ones you see the elderly pulling around. That should help the cobra breathe.
A pound of boost on a twin screw is generally worth in the neighborhood of 12 RWHP+/-. Whereas, a pound of boost on a turbo setup is worth is in the neighborhood of 20 RWHP.......
When I dyno'd 590/570 (Whipple 2.3L 140ax 3.5 upper/4lb lower) or so I saw like 15.5lbs-16lbs with my 17lb setup in Cali warm weather. On cool nights I see boost rise FAST to 17lbs and increase to about 17.5lbs-18lbs. The car feels a lot stronger too and pulls really hard. The A/F ratio on my wideband remains perfect throught the rpm range. Usually when I see boost exceed 17lbs I back off a little if I am on 91 octane though.
I'm not sure it it's the altitude or not, b/c I am not all that knowledgeable about the differences or the effect of altitude on boost. I am sure Sambandit will be able to help out here.
I'm not sure it it's the altitude or not, b/c I am not all that knowledgeable about the differences or the effect of altitude on boost. I am sure Sambandit will be able to help out here.
I'm not sure how acurate this site is, but go here select bar to psi,
enter 1.721 in the BAR box, nothing in the PSI box and 0 in the altitude. you should end up w/ 17 psi. After that you can mess around w/ the altitude and see how much of a drop you get. I know that this can't be to acurate because there's more to it than that, like outside temps, DA, blower temps etc.
I think I might just leave the setup alone, run what I have on the street and throw my 2.75 pulley on w/ a race tune.
http://www.dragsource.com/index.php?navselect=calculators&calctoview=8
enter 1.721 in the BAR box, nothing in the PSI box and 0 in the altitude. you should end up w/ 17 psi. After that you can mess around w/ the altitude and see how much of a drop you get. I know that this can't be to acurate because there's more to it than that, like outside temps, DA, blower temps etc.
I think I might just leave the setup alone, run what I have on the street and throw my 2.75 pulley on w/ a race tune.
http://www.dragsource.com/index.php?navselect=calculators&calctoview=8
IronTerp said:
well 25 rwhp doesn't seem like that much, but when your racing your buddy and he gets you by 2.5 car lengths it adds up. or when you have 100 rwhp more than your friend and he's dead even w/ you that 25 rwhp would be nice.
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