Why it is hard to produce power in the Rockies!

[Coloviper]

Okay;

So thought I would put the 06' Viper on the Dyno to see the kind of power it makes and here is what it turned out. Ran on a recently calibrated DynoJet with very accurate numbers as verified. Not too shabby for this no air altitude here in the Rockies. In the end, it pulled:

Uncorrected @ 5400 ft:

Rw-HP: 374.46
Rw-Torque: 401.25

Corrected for Sea Level:

Rw-HP: 457.53
Rw-Torque: 490.26

This altitude kicks the crap out of the power levels which is why it is hard to produce power in the Rockies. All that is done performance wise to the 06' Viper is Full Belanger Race exhaust (headers, hi-flo cats and hi-flo mufflers), Fidanza lightweight flywheel and 3.50 gears in the back.

Stock hp at the crank is suppose to be 505hp and 505lbs torque for 2006. At 18% drive train loss (assume that is accurate based on my past vehicles), that means at corrected sea level we are putting out 540 hp and just shy of 580 lbs-torque at the crank. Not too shabby!

Enjoy the pics:

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This is why the Magnusson Blower kit needs to come out NOW. When you are loosing around 75hp and 90lbs-torque just from driving here in the no-air world of the Rockies, you need to pick up the power somehow. Our house is another 800ft higher in altitude yet.

Anyway all in all, I am happy with what it threw down. Only real concern is what is going on with the Air/Fuel, car does seem to be slightly hesitant until it gets the fuel then it seems fine though the air/fuel is not as flat line as I would like to see. Anyone else seen this on a Viper dyno run or know what may be going on?

Rick

 

[AbsolutHank]

I'll trade ya some power for that 08 hood Rick!

 

[Mopar Boy]

I blame the Ford banner on the wall.... Shop was lowering your numbers as they like fords.

Was told always that lower gears reduce dyno HP. If true keep that in mind.

 

[Coloviper]

Hank, is that a straight swap, extra power for 08' hood or how do you want to handle that transaction?

Actually for what it is, the power is the power level up here. Can't fight mother nature on that as she only gives us so much air to breathe. It ***** that I am going to have to be blown to get the power I want. Wait, that just doesn't sound right!

 

[plumcrazy]

amazing how much of a difference...dang

 

[Coloviper]

Actually Mopar Boy;

They do Fords real well. That is why my 408 stroked, 95 S351R Speedster is there getting major work done to the motor with upgraded fuel system (high volume in-tank and inline pumps, high volume fuel rails, 60 lbs injectors, upgraded Aero-quip fuel lines, etc.) front to back, complete upgraded electrical/ignition system (all MSD distributors, ignition, Taylor 10.4mm wires, etc.), smallest Vortech pulley made to allow for 10 psi here at altitude), Moates chip, Snow Stage 2 Boost Cooler system, Bassani Cat X-Pipe, etc., etc., etc.

Unfortunately the Saleen is going to massively topple the Viper as initial runs are putting it over 600 rwhp and 650 re-lbs torque but still tuning. When finished, we will back off about 5%-10% to take the grenade-aspect out so it is bullet proof. Forged everything in-side allows you to have some fun safely. So far we can run a ruler across the A/F on the Saleen. As I stated, the Viper A/F seemed to be way off under 3500 rpm. Car runs fine, does not heat up, but seems a little sluggish at tip-in. Anyone have an idea what may be happening. Still on max-care warranty for another 2.5 years, if it is or maybe this is just what the cars do for some reason?

 

[Coloviper]

If Magnusson does not get out there and finally produce a kit already, then I will have to go the Paxton route. However for those that do not know, a 6 psi blower pulley at sea level is not a 6 psi blower pulley here in the Rockies at a mile high (5280+ feet). That same sea level pulley will probably only allow 3 psi or 4 psi to happen here at this altitude. So to produce a true 6 psi here at this altitude, we need to be running a 8 psi or maybe even a 10 psi pulley. Ahhhhhhhhhhhhhhhhhhhhhhhhhhhh! If it was not so beautiful here I would just move and make it simple. The joys of being in the mile high club!

For the Saleen anyway, when I drive it at lower altitudes, you basically feather it around to make sure you do not hurt it after it is tuned for altitude, otherwise you will hear a big bang and a large puff of smoke, then no noise at all. Good thing I have never heard that before. We have another tune for it for different altitudes but to be safe you just take it a bit easier.

Blowing the Viper up here with a stock chip, kind of scares me when I think about it. Knowing what I know, but as you can see, I need some power man!

 

[FLATOUT]

That's the power of DA', now think how much power an 06 could make in mine shaft air. That's why I know a gen 3 bolt on car will run 10's and a stocker could squeek in.

 

[shine]

Dang, Dynojet even... those are notorious for being generous.

 

[HyperViper]

That sux for sure. Remind me not to move to a higher elevation. Curious, who works up the calculations? What kind of math is involved here? Not doubting, I'm sure it has been proven.

 

[Coloviper]

Not sure of the exact calculation fomulas generated but they are right from DynoJet in their WINPEP7 software. As you can see, you have uncorrected numbers, then they calculate it down to sea level so in this instance, it gets calculated out at adding .22 atmosphere to correct it from 5400 ft down to sea level. Not sure how they do it exactly but the WINPEP7 software is pulling GPS data, etc. for the exact longitude and latitude, etc. where the dynojet is located so the numbers are pretty exact on the corrected. Fairly high tech!

I believe the WINPEP7 software is their latest revision and I know the Dynojet was just calibrated. Actually the guys were able to run 1/4 mile times at Bandemere NHRA track with known weight cars and back track the numbers to horsepower from their 1/4 mile and 0-60 times, etc. pulling out reaction time etc. The HP numbers were within 2% of what they registered on the Dynojet, so it is pretty close to exact.

I know the numbers **** for the altitude, because of the altitude, but when calculated back to sea level and using a realistic number like 18% drivetrain loss, they show the car is running as it should be. I mean with the small mods, it is picking up about 35 HP and 75 lbs torque. 35hp is a pretty good number for the mods from what I have seen here. I was surprised at the 75 lbs torque figure picked up and that is the one I am most exited about.

It is clear it needs to be blown at this altitude. I would just prefer a positive displacement blower as opposed to the centrifugal.

BTW Flatout, what is DA?

 

[AbsolutHank]

Density Altitude

 

[Coloviper]

Learn something new every day. Thanks!

I know when the big boys come to play at Bandemere, they run completely different blower set ups and the pulleys are little guys. Their fuel systems are also all different for running up here. It is a whole different world at altitude. You sea level folks have it easy!

 

[FLATOUT]

I have run a car in negative -1500 ft. DA' at Cecil County raceway. That's 1500 feet below sea level. Temps were in the upper 30's, humidity was zero, the track is basically at sea level and the barometer was 31.8 ish or so, very high pressure. Extremley Oxegen rich air.

Usually an 11 second car will run 13's at Bandamere.

 

[ViperGTS]

Original run flats?

 

[Coloviper]

I know! I know! Original Run Flats...... yes. As you can see, I don't have enough power to spin them up here.

Actually I was going to replace them last year but then heard the news on the new Supersports potentially coming and wanted to go that direction. Other than MMP at VOI11, car has never been on the track again. I really want to but promised the wife I would not put it back on the track until I had title in hand again. Car is almost paid for again. Actually was paid for before but we needed the extra money for an investment so I took title in hand back to the bank. That was a sad day.

Those old run flats are okay for the street for now. They have 7250 miles on them since I bought the car new in 2006 so you can see I do not drive it hard. Yah they are harder than when new but they are actually not in too bad of shape, all things considered.

Flatout, I am still trying to wrap my head around how you ran the car in (-) 1500 ft at a track at sea level? Were the conditions on that particular day just such that they were like a (-) 1500 ft DA equivalent? I know the track times at Bandamere up here have a whole new meaning. I have not had my Viper on Bandamere yet as I can only take so many blows to the ego? Ha! Ha! I just don't want to look up at the end of a run to see a 13.whatever or god-forbid a 14.whatever, due to my crappy driving and slow response.

Unless you live up in the sky like this, you can not appreciate the actual difference it truly makes. On some of our Viper runs over the passes at 14,000+ ft, you practically have to get out and push the car over the pass. I exagerate to clarify, but you can really notice a difference. A 1999 Saleen S281R I had back in the day, I actually had to jump start it at fourteener outside of Teluride because when we stopped to take pictures, the car would not restart. Turns out Saleen did not program an O2 sensor table to handle it so the car would not register enough Oxygen to "allow" it to start. True story on that one. Boy I chewed Saleen out for that one. It was scary to do that as everything is basically electronic assist, like power brakes and car was picking up speed quickly due to gravity. Good thing it turned over quickly on the first pop of the clutch. Crazy stuff! I never shut the car off on the rest of the trip back to Denver.

 

[FLATOUT]

Yes conditions were "like" -1500 feet. Dynos use correction factors for HP but there is no correction factor at the track.

 

[Camfab]

Forget the blower, just throw some JE 11:5 - 1 compression pistons in. The factory used to sell high altitude packages in the old days. No added weight up front from a blower, and just a tune away from power. Sure a rebuild isn't cheap, but it's a great solution.

 

[Coloviper]

That would be a great solution, but I am only interested in doing bolt on items. Not interested in the truly custom cut and chop nature of a twin turbo kit either, so it is supercharger all the way. Yes the factory use to sell high altitude packages and then went away from them, it seems around the late 90s.

 

[HyperViper]

No wonder my car seemed a bit slower when out on the track at VOI 11. I was missing some horsepower from the 4300' alltitude. Dynoed @ 531 hp, I bet I was down another 100

 

[Coloviper]

That will do it!

 

[TR930]

I have an 06' Coupe with Paxton on it and 3.55 gears. I am planning on going to Gen 4 rear end with 3.07 i na couple of weeks. I run the stock settings on the Paxton and at sea level it dynoed at 660 to the wheels. If you would like to meet up and feel the difference with the blower, I am in Highlands Ranch, CO.

 

[Coloviper]

Yes I would like to meet up since I am in Highlands Ranch as well. Need to PM details.

 

[HyperViper]

Wait a minute, How big is this Highlands Ranch?

 

[Coloviper]

I think we are at 100,000 people now but it is a typical California-based community so it is packed into 1 mile by 1 mile.

 

[TR930]

Coloviper,

Jsut went to see Eddie and my numbers were:


5.21 PSI boost @5500 RPM
Corrected sea level power 613.40
Corrected sea level torque 590.74

I think the altitude # were 495 HP and 478 TQ

The car is running really rich as I suspected and running lower than 8lbs boost as we both suspected. I have a feedback loop system I am going to replace with higher flowing injectors to hopefully smooth out the A/F ratio. I was running really rich just over 5,000 and there was a big dip in the graph in power. Any ideas out there on what # injectors I need?

Also, we only went up to 5600-5700 RPM so I left some ponies on the table but really just wanted to make sure nothing blew up!

 

[Coloviper]

TR930;

I stopped by Eddie's shop a little later in the day (sorry I missed you) and was able to get him to print a side by side comparison. These are the uncorrected numbers in a side by side comparison. Now from what I can tell we have:

Same environmental conditions
My car's mods are: Full Bellanger Set-up (Headers, cats and cat-back mufflers), Fidanza Lightweight Flywheel and 3.55 gears.
Your car mods are: Paxton Supercharger system, DC Performance Upgrades, stock exhaust manifolds, hi flo cats, Corsa cat-back, 3.55 gears.

The graph is as follows:

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So we are looking at an uncorrected 120 rwhp, 75 lbs-rwtorque and 5 psi gain with the Paxton/DC set-up.

I too was a little suprised at the torque difference as I would have expected more. I do believe with the proper tuning (Electronics), right sized injectors for up here, dumping that damn FMU, and a pulley change to re-gain a proper 8 psi system at altitude, you will see the numbers you dyno'd at sea level which were:

665 rw-hp and 605 rw-lbs torque.

TR-930, altitude is amazing when you consider that in your case, you are leaving 170 rwhp and 130 lbs-rw-torque on the table compared to when you had the car at sea level, by just bringng your car out here to drive at this altitude. People at sea-leve are just so spoiled!

The great thing with all this is once you have it all figured out, then I will know what to do with mine. Ah..... I think you are on your way to fixing the issues.

 

[plumcrazy]

thats a great comparison

 

[TR930]

Gonna stick my gen 4 rear end on soon and make another run on the dyno with 3.07 gears. I think I need to put on the ATI dampener on there as well. I like the power of the car now, it is more than enough for the street, just got to get the fuel system worked out and I'm good!

True, I am leaving power on the table at altitude, but so is everyone else. My car at altitude makes the same power to the wheels as a Z06 does at the crank and at sea level!

 

[TR930]

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I put the 3.07 gears in along with 10lb pulley, car runs even more rich than before!

What I did notice is that the ambient temp was 20 degrees F hotter the second time around. I really think that the combination of altitude and Air Density/temperature are really messing with the AFR. This is going to be a ***** to tune because I am running the Paxton FMU kit. So, I don't know if I need to run a higher octane fuel? Get a flash tune that advances the timing a little bit? Don't drive in hot weather? Car runs fine, but I just want to get it tuned correctly here at altitude. I have Dan and Chris at DC Performance helping me out as much as they can but I realistically don't know what they can do for me since I am here in CO and they are in CA. Altitude changes things and I think what is happening is that ambient air temp at sea level and subsequent intake Charge temps (supercharger) are WAY off here at altitude. At altitude given the same ambient air temp as sea level we run Hotter Intake Charge Temps because of lower air density which I think the car interprets as "pull timing" or "Flood system with fuel". But at altitude it is magnified since the air is literally less dense to BEGIN with relative to sea level. That's my theory anyway. It's one thing to run "hot" at sea level, but it's another to run even "Hotter" at altitude AND have less Air density. All the fuel/timing tables are slightly off.

It's a slippery slope up here because if I try to compensate for richer air/fuel with more Boost, I actually create more heat which lowers the air density even more!

Oh, and my 10lb pulley? Just a hair over 6lb boost at 5280 ft@5900 RPM.

I might just go back to the stock pulley and call it day since it only ran "slightly" rich. However if I jump back on the dyno with it on a 90 degree day I am sure it will run even richer than the first dyno.

Thoughts?