So I recently moved from DC to Denver and man, what a drop off in power. If the 3% drop in HP for every 1,000ft in altitude gain holds, my VAP Stage 2 ‘17 R is back to stock ponies…and it honestly feels like it. I can still feel certain aspects of the tune (i.e., responsiveness) but the kick in the pants from 40-50mph in 2nd is gone.

While the cooler temps help the DA, the lack of pressure is a killer.

I’ve been talking with our fine gentlemen at VAP about possible remedies and it seems a charge cooler won’t help since their initial take is that the stock set-up already runs at optimal efficiency. Their view is that the charge coolers inside the SC are the bottleneck.

Given I’m already Stage 2 (640 hp), more power doesn’t seem to be in the cards; Stage 3 only gets me another 20hp. I’ve seen 700hp figures with NOS or from Arden but even that won’t get me back to sea-level performance.

I’ve settled on the fact that until VAP comes out with an ethanol set-up for the V8 or a TVS2300-like supercharger conversion, my best friend will be their TCU tune and some weight reduction (wheels, rotors, lithium-ion battery, etc.).

Before accepting defeat, I figured I’d pitch my situation to a group of very knowledgeable gear heads.

Best,
Rick

 

I thought altitude Is a power killer only for the naturally aspirated engines, turbo charging shoud compensate the lower pressure with the compressor, May be Im wrong

 

I think it hurts all engines but my understanding is it’s least impactful to turbos given they use exhaust back pressure and can maintain ~same psi regardless of altitude. Whereas superchargers pull what they pull in terms of air from a given revolution. This might be the dumbest thing someone’s ever said, but could I put a light weight compressed air tank in the trunk lol would probably run out of air after one pull…

 

I live in the mountains at about 6000 ft. elevation. There isn't a straight section of the State highway that is longer than about 1/8 of a mile until I have dropped down to about 4000 ft. So if I am not getting the stated horsepower of either my supercharged F Type R or my turbocharged Mazda CX 5 I'd never know it as putting my foot into it would result in an unpleasant trip over a cliff !

Do you have sections of road or a track in Denver where you can do some testing ?

 

I’m glad you’re playing it safe haha…please do not drive over a cliff. I’m eager to run Pikes Peak but the whole “no guard rails thing” has me sharing your sentiment.

In terms of tracks, we have a 1/4mile at Bandimere Speedway (just outside downtown) - trying to figure out the test and tune dates. Also, each year Airstrip Attack hosts in Colorado Springs, although I read they were having insurance issues this year.

I ran a couple 0-60s out by the airport and clocked 3.7 on both. Very dirty roads though. Back in DC I was good for 3.4-3.5 consistently with the occasional 3.3. Sample size is trash but as it stands, altitude is worth 0.2-0.3 in 60 time. Real test will be the 1/4 this spring. I’ll hopefully be adding the VAP TCU tune and their new rotors (if they’re ready in time), which puts me on par or slightly quicker (all else equal) than some of the 10.9-11 second guys on here. There’s my benchmark.

 

Really, you simply need a bigger blower or to drive the one you have a bit faster. That's probably the only way to make up the loss in boost pressure. Or add nitrous....

 

There is the wastegate valve controlling the maximum air pressure does not exced the preset value. I think the compressor can give more air boost so that it easy can compensate the lower air altitude pressure to get the same power.
Anyway there is another (positive) altitude effect: the air is more rarefied, this improve a lot the areodinamic, so you can get better times in the long acceleration like 100-200.

 

I love the positivity! And I’ll keep thinking on this compressor concept and if there’s a way you could recharge the tank while driving.