I know you can't really rely on them but I have used about ever 1/4 mile calculator out there and all of them put me at 12.9-13.1. Using 475rwhp and a 5400lb weight. Now obviously I have done better than that with a 12.7 on fouled out plugs but I really don't see running better than a mid 12. If I do my head may explode. LOL.

 

^^lol

Positive thinking right there!

 

So, I finally received an updated tune from JDM and put the stock tires back on. I went from 350 hp/411 tq to 386 hp/450 tq. I'm not terribly concerned about the numbers although they seem low for my mods, but the psi is the concerning part...only 7psi of boost. I verified this with two gauges and looked for any leaks and found nothing. The whipple tech said nothing is wrong because with a 3.0 pulley (10psi) I should expect 2psi drop for elevation (4200 ft) and 1 psi drop for LT headers and free flowing cats. Let me know what you guys think. Also, is there anyone supercharged at elevation that has found similar results? My local dyno tuner says if I want to see more boost I simply need to put a larger crank pulley on, is 3psi drop really legitimate or is something wrong I'm not finding?

 

Had mine rolled at 3500ft with low RW. Mine held 10.4 from 3000 upto 5400 or summit. That's a 2 psi drop over the stock 7.5 + 6psi SB. I am using a .200 larger upper over stock that might have stolen a pound or two.

Iam at 4500ft at home. I was told 10RW loss every 1000ft.

 

I'm at 5300 ft. I use a 2.75" upper pulley and see approx. 10# of boost. My dyno numbers are below. Stock exhaust manifolds with a Gibson catback.

Lee

 

Thanks, this helps! Have you had any problem with belt slip with that small of upper pulley?

 

How are you guys pulling these numbers at "altitude" and I can't break 400 at sea-level" with good mods?

I'm working on a solution though.

 

I had one instance where belt slip began to occur, and it was time to change the belt anyway. The desert atmosphere here dries & cracks belts somewhat faster than other locations.

Lee

 

Perhaps it's your 23" wheels? Are you getting enough fuel?

Lee

 

I think I'm going to drive it for a couple of weeks and then order some different pulleys to try and get her to pull 10# at my elevation. Also, I'm going to sell my sct tuner so if anybody wants it for a good deal let me know.