Horsepower and 1/4 mile Experts Please Comment

[redlineviper]

I am a newby with vipers, but I thought these ran quicker than this but with a good launch but I guess not. What is the best 1/4 mile run with a bone stock SRT10?

Looking forward to the dyno run tomorrow. If it makes good power then the mystery really thickens.

Ran a 11.7@118 in bradenton stock down to the aircleaner but 1.8 short time, Best mph was 119 on a 12.0 pass.

A track has two timers at the top end of the track that are 60' apart. Your mph is the average speed through that 60' area, its possible they set them up 60' too far up and would explain why you have a good 1/8 mph but a lil lower 1/4 mph.

 

[FikseGTS]

my GT-R ran 126.8 at Bradenton and 122.75 at Moroso/PBIR, same setup, similar weather.... not many variables with driving, the launch is the same each time with the AWD.....

Ran a 11.7@118 in bradenton stock down to the aircleaner but 1.8 short time, Best mph was 119 on a 12.0 pass.

A track has two timers at the top end of the track that are 60' apart. Your mph is the average speed through that 60' area, its possible they set them up 60' too far up and would explain why you have a good 1/8 mph but a lil lower 1/4 mph.

 

[Speedfreak]

Well, some mixed news with the dyno test. The good news is there is nothing wrong with this engine. The bad news is it is running extremely rich at WOT (less than 10:1 A/F) which is definitely killing some sizeable power. Actual horsepower at the rear wheels was 428. Given this was a dual eddy current dyno and not an interia dyno like a dynojet the power number seems pretty good. Most of the dyno tests I have seen on the forum here are around 440-450 stock (correct me if I am wrong). I know these cars run rich a WOT stock but below 10:1 has got to be killing 10-20 HP.

With the power number in mind, it seems the trap speed is still too low but I will find out when I run it again Friday night going through the traps in third gear.

Is there anything I can do to adjust this A/F issue absent an aftermarket computer retune?

 

[MarcRoth]

Any one running a 3:73 gear?? Ifso what gains were made?

 

[Newport Viper]

Here is a sample on a dyno jet at DCPerfomance on the same day....

Name Model Horsepower/Torque Modifications

1. Dave Cawthorne Gen 2 422.30/461.87 Modified
2 .Lance Kouchi Gen 2 397.43/440.11 Stock
3. Dave Kuzmiak Gen 3 444.28/472.65 Stock
4. Eddie Arguelles Gen 3 452.10/475.38 DC Tune
5. Steve Shaw Gen 4* 521.42/494.45 Stock
6. Norman Greitzer Gen 4 * 507.05/481.33 Stock
7. Angel Calderon Gen 3 424.34/443.57 Stock
8. Eddie Reinsma Gen 3 436.30/464.02 Stock
9. Steve Smoot Gen 3 658.65/580.85 Paxton
10. Kobi Sial Gen 4* 558.11/528.45 Headers
11.Chris Sienecki Gen 3 484.31/473.68 Headers
12. George Balejian Gen 3 405..95/449.72 Stock
13. Peter Hausherr Gen 2 426.09/466.80 Headers
14. Kaia Rexroad Gen 3 444.52/470.57 Stock
15. Sean Casey Gen4* 563.44/526.85 Headers
16. Adam Melikoff Gen 4* 515.32/482.67 Stock
17. Michael Burgoyne Gen 3 477.52/502.68 DC Tune/Headers
18. Mark Kasparoff Gen4* 523.95/481.24 Stock
19. Rick Hollis Gen 2 855.82/798.75 Paxton
20. ErnieTaylor Mustang 249.28/247.93 Stock
21. M. Greenberg Gen 2 636.17/562.37 Race Car


* 2008 Viper

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[pe5787]

Any one running a 3:73 gear?? Ifso what gains were made?

Or 3:55's.

 

[MarcRoth]

What.... all of these members and no one has a 3:73 car and ran it at the track?? Or can say what if any gain in the 1320? hmmmm

 

[Speedfreak]

Here is a sample on a dyno jet at DCPerfomance on the same day....

Name Model Horsepower/Torque Modifications

1. Dave Cawthorne Gen 2 422.30/461.87 Modified
2 .Lance Kouchi Gen 2 397.43/440.11 Stock
3. Dave Kuzmiak Gen 3 444.28/472.65 Stock
4. Eddie Arguelles Gen 3 452.10/475.38 DC Tune
5. Steve Shaw Gen 4* 521.42/494.45 Stock
6. Norman Greitzer Gen 4 * 507.05/481.33 Stock
7. Angel Calderon Gen 3 424.34/443.57 Stock
8. Eddie Reinsma Gen 3 436.30/464.02 Stock
9. Steve Smoot Gen 3 658.65/580.85 Paxton
10. Kobi Sial Gen 4* 558.11/528.45 Headers
11.Chris Sienecki Gen 3 484.31/473.68 Headers
12. George Balejian Gen 3 405..95/449.72 Stock
13. Peter Hausherr Gen 2 426.09/466.80 Headers
14. Kaia Rexroad Gen 3 444.52/470.57 Stock
15. Sean Casey Gen4* 563.44/526.85 Headers
16. Adam Melikoff Gen 4* 515.32/482.67 Stock
17. Michael Burgoyne Gen 3 477.52/502.68 DC Tune/Headers
18. Mark Kasparoff Gen4* 523.95/481.24 Stock
19. Rick Hollis Gen 2 855.82/798.75 Paxton
20. ErnieTaylor Mustang 249.28/247.93 Stock
21. M. Greenberg Gen 2 636.17/562.37 Race Car


* 2008 Viper

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Wow! This is really helpful. Looks like my assumption was pretty much correct. Finally got the actual printout of my dyno run and it was even better than I thought 435HP vs. 428 originally. And given the sub 10 A/F at 3000 RPM plus I think my motor is probably about 445 with the normal 10.5 rich mixture seen in most cars. So now I just need to get back to the track.

 

[Speedfreak]

What.... all of these members and no one has a 3:73 car and ran it at the track?? Or can say what if any gain in the 1320? hmmmm

I'll be puting 3.55s in mine in the next two weeks and will give a drag strip report thereafter. Seems like mixed opinions on the effect. Some say none, and others say they help. My experience has been that if traction is as good with the lower gears 1/4 mile performance improves about .1 to .15. especially given the very tall rearend ratio to begin with. Getting this car to launch hard and not bog is not easy with the stock gears. A 3.55 would seem to be a very nice compromise for the power band given the tall tire, etc. We'll see though.

 

[1BADGTS]

Honestly it all comes down to the driver

 

[Speedfreak]

A very exciting night at the track and several interesting discoveries about drag racing a viper. Weather conditions were practically perfect: temps in the 40's, high pressure and low humidity. We don't get many drag racing days like this in Florida and it really makes it something. The track condition was excellent and several pro stock cars doing testing on this new track set world record times (one I watched ran 6.51 @213) but they don't count as there was no event they were participating in.

My expectations were high and was hoping to set some smoking times and sort out the MPH mystery. Well I did figure out the MPH mystery and it was totally by accident. One other thing that goes on with Florida racing is they often run at night because of the heat. It so happens that the track opens at 4:00 but racing usually starts around 5:00 to 5:30. That is dusk this time of year so it is dark pretty fast. My first pass was an 11.98 @ 120.04 at about 5:45 p.m. when it was still daylight. The car felt incredibly strong and the power shift from 1-2 was unbelievable and so violent I nearly put the beauty in the wall. Fish tailed and wheel hopped violently and left a lot of time on the table in the process. I decided to forego the 1-2 powershift in favor of a speed shift to better control the car and traction thereafter. This made immediate improvement and I clocked an 11.89 and then an 11.86 @ 121.61. The outside temperature was dropping fast now and the car just kept getting stronger and stronger. Next pass saw a mediocre e.t. but a 122.6mph (wow). On the return from this pass it was nearly dark so I turned on my lights on the return lane back to the pits and to pick up my slip. Didn't think much of it. Grabbed the slip and went straight back to line up. I got right back on and laid down the killer pass: 11.80 @ 120.3 with a 1.84 short time. I was fired up, but thought what in the hell happened to the MPH? Well guess what gang - IT WAS THE LIGHTS BEING ON. Believe it or not the headlights will cost you 2.3 MPH (that is over 20 HP at the wheels) in the quarter mile. I would have never believed it but it is true. Apparently those lights **** a hell of alot of juice and that big alternator is kicking on at the top end of the track. On my previous trip I ran entirely in the dark and had the lights on the whole time!!!!! 115.5 plus 2.3 equals 117.8 mph!!! which is where it should have been. I figured it out when I sat in line a long time waiting and killed the engine. When I restarted it I only turned on the parking lights and behold the MPH came up 1.7 on the next two passes. Sooooooo

Lesson 1: Full headlights costs 2.3 MPH in quarter and parking lights cost about .5 MPH. In my last pass I ran 122.9 with no lights on at all. Makes reading the tach tough but necessary.

Lesson 2: I most assuredly would have turned an 11.7 pass on my 11.80 @ 120.3 if I had had the damn lights off. Really pissed me off after I figured it out. I got close with an 11.82 and 11.84 after that but just couldn't quite make it come together again. Both these passes were with the lights on. So the best pass was:

60' 1.841
330 5.072
1/8th 7.709
MPH 94.31
1000 9.943
1/4 11.807
MPH 120.29

Lesson 3 - The runflat likes very little time between runs. If you can come straight back and get back on the track quickly, its traction improves markedly. It builds heat on the run (from the high speed, etc.)and retains some of that for a while. Also, the pressue in the tire will keep creeping up when you do this so check it often. Best tractions seems about 24-25 psi. I had much better luck doing this than going for prolonged cool downs between runs as most people do for improved engine power. Obviously, the engine makes all the power you need. It is getting it to the ground that is the challenge.

Lesson 4 - Burn out strategy. In keeping with above, do a double burn out. Go around the water, then back up to just ahead of it. Do a hard burn out (2-3 seconds) and then hit the brakes, wait a few seconds. You should still have enough room to do one more short burn out before staging. On this second one you will notice the tires get alot stickier. With this strategy you can leave aggressively at about 3000 RPM with full traction on launch and consistent 1.8 short times.

By the time I figured out the light mystery I got in only 2 more passes. Bummer, as I am sure I could have broke 11.7 if I had stuck around. Last run was 11.86 @ 122.99 with 1.89 short time. Another 1.84 or better and 11.7 something would have happened for sure. As I am writing this the density altitude at the track now is -1430 feet!

By 7:30 it was getting very crowded and I had to head home. They were running until 11:00, oh well. This may be it for me in a stock viper as I am going to begin modding the car with a gear change, etc. I am really impressed with this powerplant though. By my calculations this thing was making 515HP at the wheels toward the end (122.9 mph and 3600lbs.) Incredible.

Last question: How much do PS2s help traction. I was giving up alot of time on the 1-2 shift. If the PS2 would allow a good 1-2power shift even an 11.6 might be in the making.

 

[1BADGTS]

I have never heard of the headlights being on resulting in losing 20 horsepower .On stock radials a hard,2-3 second burn out does absolutely nothing but take mileage off the tires. Most likely you best runs were from the engine being COLD(that RESULTYS IN ADDED POWER.)and hitting the run better (driver wise )than the others

 

[Ray W]

Great results. I think cooler weather and better driving are the contributing factors. The headlight thing is a little questionable. The best way to test your theory would be on a dyno not at the track. I think the alternator puts a constant load on the engine which increases as the rpms go higher,much like a supercharger. Only the amp production changes with low to high rpms which is controlled by the regulator to bleed off the extra currrent much like a pop-off valve on a blower. You can add a switch to kill the alternator but the belt load will still be present.

 

[ivanrho]

Great results. I think cooler weather and better driving are the contributing factors. The headlight thing is a little questionable. The best way to test your theory would be on a dyno not at the track. I think the alternator puts a constant load on the engine which increases as the rpms go higher,much like a supercharger. Only the amp production changes with low to high rpms which is controlled by the regulator to bleed off the extra currrent much like a pop-off valve on a blower. You can add a switch to kill the alternator but the belt load will still be present.

Ray, are you going Sunday?

 

[Speedfreak]

I have never heard of the headlights being on resulting in losing 20 horsepower .On stock radials a hard,2-3 second burn out does absolutely nothing but take mileage off the tires. Most likely you best runs were from the engine being COLD(that RESULTYS IN ADDED POWER.)and hitting the run better (driver wise )than the others

Incorrect. The engine was NEVER cold during any of the runs and the headlight change was documented by 3 runs before and 2 after, all within 1/2 hour with that being the only change. First 3 runs the MPH was 120.3, 120.5 and 120.21 which included the best run. Then the car sat for less than 5 minutes in line which is when the engine was turned off. Then the last two passes which were without lights and run back to back with me finishing and pulling immediately back up to the line after picking up my slip. Last 2 were 122.6 and 122.9 with the ONLY change being the headlights. Moreover a better e.t. is not going to have much impact on trap speed. But the last two runs were both 11.8s like the best runs before so make of it
what you want. I ran a 12.34 on one run where traction did not cooperate and the trap speed changed on .23 mph.

The nest time I make it to the track I am going to try this test again to see if the same thing happens since I am aware of it now.

As to the burnout strategy. Differenct strokes for different folks. Just reporting what worked for me.

 

[Speedfreak]

Great results. I think cooler weather and better driving are the contributing factors. The headlight thing is a little questionable. The best way to test your theory would be on a dyno not at the track. I think the alternator puts a constant load on the engine which increases as the rpms go higher,much like a supercharger. Only the amp production changes with low to high rpms which is controlled by the regulator to bleed off the extra currrent much like a pop-off valve on a blower. You can add a switch to kill the alternator but the belt load will still be present.

Again, I am not really sure why the lights had impact but they did. My assumption is that the current draw was going up substantially as I ran and loading the alternator more, increasing the parasitic loss. But frankly, I am no charging expert. I am not at home, but when I return on the weekend I will post the exact times of one of the last nonheadlight runs and you guys can draw your own conclusions.

A dyno would probably give some indication of this affect but not what the track would. A dyno run is quick and runs the engine very briefly and only to the top of the rpm band once. This does not take into account the multiple shifts, rpm changes and load on the engine in each gear a drag race does.

 

[1BADGTS]

Ask ANY of the EXPERT level drivers out there (guys capable of running 11.5s-11.7 in bone stock Gen 2 Vipers )and they will tell you that heating up a STOCK radial tire (its not a drag slick )does absolutely nothing but waste tire life )If the engine was not run colds it most likely that you quite simply drove better during that run .Its ALL in the driver.( For instance put a Furman or a Smith in a stock 450 hp Gen 2 and they can probably beat 90% of the guys out there in a 600 HP Gen 4 giving up 150 horsepower.)

 

[Ray W]

I am going along with this against my on good judgement but stranger things have made horsepower in the past so here goes. 2-3 mph and 2 tenths of a second can be measured as hp. on a dyno. Make four runs with the car hot so that temp is not a factor. You will be looking for about a 20hp difference. Run it back to back till done.First no lights,second with lights etc. If your theory is correct there will be a difference in total hp. of at least 20hp from lights on to lights off.

 

[Ray W]

Yes,Ivan I am going if you guys still want too after Saturday's trip. I don't know where Dave's new house is so give me a call.

 

[1BADGTS]

I am going along with this against my on good judgement but stranger things have made horsepower in the past so here goes. 2-3 mph and 2 tenths of a second can be measured as hp. on a dyno. Make four runs with the car hot so that temp is not a factor. You will be looking for about a 20hp difference. Run it back to back till done.First no lights,second with lights etc. If your theory is correct there will be a difference in total hp. of at least 20hp from lights on to lights off.

Ray when Evan Smith used to race my heavily modded GEN 2 in competition or for a magazine article the car differed 2 tenths and a few mph per run (and that car made HUNDREDS of runs down the strip at Englishtown.)and that was with one of the BEST(and consistant ) drivers in the country on stock tires behind the wheel.One run the car would go 11.2 at 132 the next it would run 11.4 at 129..The track and change ,headwind,drivers 60 foot ect ect ect .

 

[1BADGTS]

Interesting story that relates directly to the above .In 2003 John Coletti Former head of SVT (father of the Ford GT )wanted to see what the prototype Ford Gt was capable of in stock form and with the boost turned up .Coletti shipped a prototype Ford GT to Englishtown NJ and flew in with about 10 Ford engineers (reconfigure cars fuel management =added boost .All work done at the track )Evan Smith was the driver (story was written in Muscle Mustang and Fast Ford )That car that particular day was run to the point that a new clutch went in an afternoon .Et (boost turned up )ranged from 10.8-11.4 .Mph ranged from 129-133 .Basically the car was all over the board from run to run .

 

[Speedfreak]

Ray when Evan Smith used to race my heavily modded GEN 2 in competition or for a magazine article the car differed 2 tenths and a few mph per run (and that car made HUNDREDS of runs down the strip at Englishtown.)and that was with one of the BEST(and consistant ) drivers in the country on stock tires behind the wheel.One run the car would go 11.2 at 132 the next it would run 11.4 at 129..The track and change ,headwind,drivers 60 foot ect ect ect .

I don't know your car nor any of the conditions surrounding the runs so I really can't comment on yours. What I do know is that the first time I was out I ran 12 passes and the trap speed didn't vary by .5 MPH (115-115.5). So in this second outing for it to vary 2.6 MPH when the e.t., short time, etc. are varying by 3-4 hundreths (not tenths) is not plausible, especially when you consider the short time frame they were run in and that I backed up the times and MPH repeatedly under the same circumstances (lights vs. no lights).

While I may be new to vipers, I am not new to the concepts or pratice of drag racing. I have been doing it 25 years since I was a teenager and have taken a few thousand passes. I believe my driving (and the consistency of it - 3-4 hundreths in short time and e.t.) makes that as the variable in this circumstance very unlikely.

Even in the blown runs where I was turning say a 12.30 there was still no where near that variance in MPH.

My experience is that the more power a car makes, particularly with power adders and blowers/turbos etc. the more variance I have seen in trap speed because the actual amount of horsepower being made run to run varies significantly. Your GENII with a trap of around 130 would be in that category (that is alot of power) and with inconsistent traction and 2-3 tenths e.t. difference I am not surprised by your results. But with a bone stocker like I am running that simply isn't the case. And I have not seen any such wide variances in MPH and in fact the opposite. The only thing that has been changing mine significantly is the change in atmospheric conditions.

As to the tire issue. I don't see these tires as a typical radial (I don't see any disclaimers on my T/A radials telling me not to drive in near freezing temperatures). While they are no drag slick they are FAR more temperature sensitive than a normal radial. If temperature didn't affect traction on this tire then why does it spin like it is on ice right out of my drive way and grip much better after a couple of miles? The BFG radial T/As on my vette have no such difference. The bottom line is this tire likes heat and the more you can generate the better it grips. The worst traction I got with this tire was with my first visit to the track where I gave the car some longer cool down periods between runs. The traction stunk as the brief burn out did not heat it adequately. By contrast my technique the second time out was to take no time between runs. This resulted in the tire being heated in the burnout then run to nearly 125 in the quarter, then driven immeiately back down, then burned out again twice then restaged and run. Overall, I believe this kept the tire temp up significanly from normal and really helped traction. The burn out method I think helped but it wasn't the whole story.

 

[1BADGTS]

I understand what your saying about the 600 plus horsepower cars varying et-trap speeds but believe me the 450 hp cars also do it.Ihave been on hand for MANY a MAG drag test.The test in which Smith set the mag drag record in the stock 2001 Gen 2 roadster(11.7 at 117) his times (ET wise and mph varied from 11.7-12.0 and traps varyied 116-121 over the coarse of 20 or so runs for the day.Honestly i have never been at a test where they did not.

 

[1BADGTS]

PS as far as tires ect ALOT of this has to do not with the burnout but track prep (part VHT).At Englishtown from lane to lane it can vary.Same day ,same car,same driver in one lane (stock PilotS hes getting 1.6- 1.8s )other lane getting 2.0.If your running a public test and tune night that track can change dramatically over the coarse of the night on a July night in NJ there might be a thousand passes made over the coarse of a 5 hour period.

 

[Speedfreak]

PS as far as tires ect ALOT of this has to do not with the burnout but track prep (part VHT).At Englishtown from lane to lane it can vary.Same day ,same car,same driver in one lane (stock PilotS hes getting 1.6- 1.8s )other lane getting 2.0.If your running a public test and tune night that track can change dramatically over the coarse of the night on a July night in NJ there might be a thousand passes made over the coarse of a 5 hour period.

Good point. What is your opinion on PS2 vs. run flat. I know noboby likes the run flat but have you run both on your car? How much difference did they make in your opinion? I think I could really make this car fly with some better grip. Just getting the 1-2 shift to the ground would seem to be worth 1-2 tenths.

 

[1BADGTS]

Good point. What is your opinion on PS2 vs. run flat. I know noboby likes the run flat but have you run both on your car? How much difference did they make in your opinion? I think I could really make this car fly with some better grip. Just getting the 1-2 shift to the ground would seem to be worth 1-2 tenths.

Speed i never ran my Gen 3 (runflats )down the track .I only owned the car for a month then a great deal came on the Gen 4 and i traded the car in to Buhler.My Gen 2 and Gen 4 had the Pilots which do feel sticker.Let me tell you though the times you getting out of your stock Gen 3 are fantastic .An 11.8 is truely exceptional and probably the best i have heard of bone stock with the runflats which have a reputation of being TERRIBLE to hook up with.In cooler weather (if the track is VHT to the max )you should be near mid 11s.On the Gen 4s with their trap speeds in the 130 mph range the best times so far are 11.0(Furman )-11.3 (Smith).

 

[Ray W]

Ray when Evan Smith used to race my heavily modded GEN 2 in competition or for a magazine article the car differed 2 tenths and a few mph per run (and that car made HUNDREDS of runs down the strip at Englishtown.)and that was with one of the BEST(and consistant ) drivers in the country on stock tires behind the wheel.One run the car would go 11.2 at 132 the next it would run 11.4 at 129..The track and change ,headwind,drivers 60 foot ect ect ect .

I agree with what you said. Because of varying conditions as you mentioned the dyno is the only way to prove the horsepower loss theory. The dyno in this case will eliminate all other factors. Wind,tire spin,track prep,driver,etc. If the lights truly are causing a power loss it will show up. The load on the alternator is either present or is a non-factor.

As far as runflats go the warmer the better. And the new tires on the 08 have hooked up better than any stock tire to date.

 

[1BADGTS]

PS one of the main advantages of a -mag private test session (besides being able to cool the cars down thourghly with ICE BAGS between runs )is the ability to tailer a track with VHT to make sure there is MAX TRACTION.At E-Town for example i have seen them track prep with VHT to the extent that its so sticky that it will pull you sneakers off your feet walking on it .One time stock Viper halfshafts were breaking.

 

[Flyntgr]

My stock '08 tachs 1300 rpm's at 80mph. Your gears should be right on. It runs consistent 127mph and about 12 flat in the quarter, as did the DC Viper I drove at VOI. I'm old and decrepit, though. A good driver would definitely be in the elevens with my car. Besides, it's blue with white stripes, so it's gotta be faster than most Vipers.

 

[1BADGTS]

My stock '08 tachs 1300 rpm's at 80mph. Your gears should be right on. It runs consistent 127mph and about 12 flat in the quarter, as did the DC Viper I drove at VOI. I'm old and decrepit, though. A good driver would definitely be in the elevens with my car. Besides, it's blue with white stripes, so it's gotta be faster than most Vipers.

The best i saw on my 08 was 11.3 at 129.7
once again a professional driving in fair horsepower weather.Jamie Furman ran a flat 11.0 with his.On a cold night if the track was prepped properly a 10 second run probably is within reach (bone stock on stock pilots)