Back to the dyno for some better numbers. How'd I do?
FWIW trapping 142 @ 3350lbs going by weight and trap speed comes out to about 740hp. These calculators calculate crank HP. Drop 12% for drive train losses and you are looking at around 652whp to put 3350lbs at a 142 trap speed. It doesn’t take 850+whp to hit 140 traps at that weight. But if we get 100 dyno guys claiming that it does… so be it, I’m tired of arguing with them.
On the dyno it went positive at 3600 and peaked at about 6100. Basically kept building through the whole pull. Haven't done a full 3rd gear pull on the street to see if it's any different. The top of 3rd is almost 160mph, so not real anxious to go to jail.
Under normal driving, you can't really tell it's turbocharged.
The cam is 221/225 .622/.621 115+3
Under normal driving, you can't really tell it's turbocharged.
The cam is 221/225 .622/.621 115+3
Keep up the good work and report back with Track Numbers!
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From: Avon, Ohio
Claiming 872whp @ 21lbs on a bone stock ls1 ,including the OEM cam (Which was your original claim.) Isn't the same thing as claiming 860 on a cam’d 6.0 @ 20lbs. I admit I was being kind and gave up on bashing dyno posts. They are what they are…
FWIW trapping 142 @ 3350lbs going by weight and trap speed comes out to about 740hp. These calculators calculate crank HP. Drop 12% for drive train losses and you are looking at around 652whp to put 3350lbs at a 142 trap speed. It doesn’t take 850+whp to hit 140 traps at that weight. But if we get 100 dyno guys claiming that it does… so be it, I’m tired of arguing with them.
FWIW trapping 142 @ 3350lbs going by weight and trap speed comes out to about 740hp. These calculators calculate crank HP. Drop 12% for drive train losses and you are looking at around 652whp to put 3350lbs at a 142 trap speed. It doesn’t take 850+whp to hit 140 traps at that weight. But if we get 100 dyno guys claiming that it does… so be it, I’m tired of arguing with them.
And to clarify I trapped 146mph at 18psi. I made 740whp @16psi.
From where I am sitting, that math still works out great.
I had forgotten that this was a high density altitude combination. Definitely would go mid 8's or faster at sea level! At altitude I think your goals are still attainable.
Hope you enjoy it!
Hope you enjoy it!
His cylinder pressure at 5000-7000' DA is much less than the same combination at sea level would be. This necessitates a smaller camshaft to work with the amount of cylinder pressure and effective compression ratio of his engine at altitude.
If it were at sea level it would be several degrees larger and have a little more overlap.
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The reason the cam is smaller is because he races at 5000-7000' DA. At that kind of density altitude the amount of available air mass is much less than it is at sea level. I use an earlier intake closing event and a later exhaust opening event combined with less overlap because of the altitude.
His cylinder pressure at 5000-7000' DA is much less than the same combination at sea level would be. This necessitates a smaller camshaft to work with the amount of cylinder pressure and effective compression ratio of his engine at altitude.
If it were at sea level it would be several degrees larger and have a little more overlap.
His cylinder pressure at 5000-7000' DA is much less than the same combination at sea level would be. This necessitates a smaller camshaft to work with the amount of cylinder pressure and effective compression ratio of his engine at altitude.
If it were at sea level it would be several degrees larger and have a little more overlap.
The reason the cam is smaller is because he races at 5000-7000' DA. At that kind of density altitude the amount of available air mass is much less than it is at sea level. I use an earlier intake closing event and a later exhaust opening event combined with less overlap because of the altitude.
His cylinder pressure at 5000-7000' DA is much less than the same combination at sea level would be. This necessitates a smaller camshaft to work with the amount of cylinder pressure and effective compression ratio of his engine at altitude.
If it were at sea level it would be several degrees larger and have a little more overlap.
His cylinder pressure at 5000-7000' DA is much less than the same combination at sea level would be. This necessitates a smaller camshaft to work with the amount of cylinder pressure and effective compression ratio of his engine at altitude.
If it were at sea level it would be several degrees larger and have a little more overlap.
A cam would not have helped my total power output as I was out of fuel. It would have only givem me the potential to make the same power with less boost. Wouldn't you agree?
And to clarify I trapped 146mph at 18psi. I made 740whp @16psi.
From where I am sitting, that math still works out great.
And to clarify I trapped 146mph at 18psi. I made 740whp @16psi.
From where I am sitting, that math still works out great.
It is still listed this way on the SBE dyno top ten dyno list. And 890 was the claimed uncorrected numbers I believe...
https://ls1tech.com/forums/forced-in...end-lsx-s.html
8)coltboostin 872 whp@21psi Twin Billet 67mm (on3) Bone Stock LS1
Last edited by Forcefed86; Feb 25, 2016 at 12:23 PM.
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Joined: Jun 2013
Posts: 1,163
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From: Avon, Ohio
You’re inability to fuel the engine has nothing to do with what is or isn’t possible as far as power output goes per pound of boost on a factory engine. Your original numbers were less than believable, which is why you were “ridiculed for having "BS" dyno numbers”. That’s all there is to it.
It is still listed this way on the SBE dyno top ten dyno list. And 890 was the claimed uncorrected numbers I believe...
https://ls1tech.com/forums/forced-in...end-lsx-s.html
It is still listed this way on the SBE dyno top ten dyno list. And 890 was the claimed uncorrected numbers I believe...
https://ls1tech.com/forums/forced-in...end-lsx-s.html
I guess everyone is full of ****!Fuel is fuel. If I only have fuel for a safe 850 HP worth of airflow, a cam or lack there of is not going to magically change that-it will only change what RPM and with what intake back pressure (boost) I run out of fuel at-but it would still be making about the same power. The only confusion was caused admittedly caused by me because the boost numbers I quoted where low. Max boost on the log was almost 24psi on the map. My boost gauge reads 2-3psi low evidently.
870 was uncorrected. The list should reflect that. If not, I will edit it. I will be sure to log boost on the dyno next time.
I promised a full car shot, so here it is. Nothing special.
Also, have a question for Martin and some of the other more experienced turbo guys here. My peak torque is lower than I expected compared with HP, and much, much higher in the RPM range. What factors tend to cause this? Is it tune related or more to do with the combo?
Also, have a question for Martin and some of the other more experienced turbo guys here. My peak torque is lower than I expected compared with HP, and much, much higher in the RPM range. What factors tend to cause this? Is it tune related or more to do with the combo?
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Boost response.
It sounds like your boost curve is more like a blower than a responsive turbo set-up. If you aren't reaching max PMP ~2,000RPM before redline then you are leaving a lot of power on the table.
I looked at the dyno sheet & from what I saw I had a feeling it was responding the way you said. That's why I asked, but I didn't want to say anything if you are happy with it.
Converter can have a big impact there as well as other factors. Dyno loading could be one of them if it responds differently on the street. If it reacts differently then ignore the dyno numbers & just move on.
It sounds like your boost curve is more like a blower than a responsive turbo set-up. If you aren't reaching max PMP ~2,000RPM before redline then you are leaving a lot of power on the table.
I looked at the dyno sheet & from what I saw I had a feeling it was responding the way you said. That's why I asked, but I didn't want to say anything if you are happy with it.
Converter can have a big impact there as well as other factors. Dyno loading could be one of them if it responds differently on the street. If it reacts differently then ignore the dyno numbers & just move on.
Last edited by gtfoxy; Feb 25, 2016 at 09:45 PM.
GTfoxy is dead on.
Was the converter flashing around 5300-5400rpm?
Where was peak boost made?
My car with a 370" and a S476 V2 compressor wheel and T6 1.32 96mm exhaust arrangement made 1080rwhp and 970rwtq. Peak torque was @5700-5800rpm, but the converter was flashing right around that rpm as well. I think it would of shown more torque had the converter been able to grab the engine earlier around 5300-5500.
I see this somewhat often with turbo engines unless it's on a mustang dyno with appropriate load.
Was the converter flashing around 5300-5400rpm?
Where was peak boost made?
My car with a 370" and a S476 V2 compressor wheel and T6 1.32 96mm exhaust arrangement made 1080rwhp and 970rwtq. Peak torque was @5700-5800rpm, but the converter was flashing right around that rpm as well. I think it would of shown more torque had the converter been able to grab the engine earlier around 5300-5500.
I see this somewhat often with turbo engines unless it's on a mustang dyno with appropriate load.
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He said max boost was at 6,100RPM on the dyno(last post pg1).
If it responds the same on the street, & his shift recoveries are where they should be then it could be tune related. I don't know how they should respond as I have not tried this combo, but I was thinking given his combo with .69 A/R's, ~5,000RPM would be where I would have guessed it would be, but again haven't been there personally & I don't know how much the altitude would effect it.
One thing though is if it does act like this & nothing is really whack, it will be easier on engine internals. Won't ET the same as if it had better response, but it will MPH about the same.
For me OP, personally, I always shoot for a combo that yields max boost at the shift recovery RPM of @ a miminum a few 100RPM before. This ensures you have max torque available at the recovery RPM & helps keep the car accelerating harder rather than having to ramp back up on boost. Ensures you get that warped 9-iron to the forehead & the hand around your spine pulling you back in the seat feeling when you grab the next gear.
Traction is a limiting factor here & everyone has their own preferences based on their needs, wants & racing style.
If it responds the same on the street, & his shift recoveries are where they should be then it could be tune related. I don't know how they should respond as I have not tried this combo, but I was thinking given his combo with .69 A/R's, ~5,000RPM would be where I would have guessed it would be, but again haven't been there personally & I don't know how much the altitude would effect it.
One thing though is if it does act like this & nothing is really whack, it will be easier on engine internals. Won't ET the same as if it had better response, but it will MPH about the same.
For me OP, personally, I always shoot for a combo that yields max boost at the shift recovery RPM of @ a miminum a few 100RPM before. This ensures you have max torque available at the recovery RPM & helps keep the car accelerating harder rather than having to ramp back up on boost. Ensures you get that warped 9-iron to the forehead & the hand around your spine pulling you back in the seat feeling when you grab the next gear.
Traction is a limiting factor here & everyone has their own preferences based on their needs, wants & racing style.
Last edited by gtfoxy; Feb 26, 2016 at 04:36 AM.
Less than believable, but replicated by many (including the OP)? I guess everyone is full of ****!
Fuel is fuel. If I only have fuel for a safe 850 HP worth of airflow, a cam or lack there of is not going to magically change that-it will only change what RPM and with what intake back pressure (boost) I run out of fuel at-but it would still be making about the same power. The only confusion was caused admittedly caused by me because the boost numbers I quoted where low. Max boost on the log was almost 24psi on the map. My boost gauge reads 2-3psi low evidently.
870 was uncorrected. The list should reflect that. If not, I will edit it. I will be sure to log boost on the dyno next time.
I guess everyone is full of ****!Fuel is fuel. If I only have fuel for a safe 850 HP worth of airflow, a cam or lack there of is not going to magically change that-it will only change what RPM and with what intake back pressure (boost) I run out of fuel at-but it would still be making about the same power. The only confusion was caused admittedly caused by me because the boost numbers I quoted where low. Max boost on the log was almost 24psi on the map. My boost gauge reads 2-3psi low evidently.
870 was uncorrected. The list should reflect that. If not, I will edit it. I will be sure to log boost on the dyno next time.
Tell yourself whatever you need to, I’m done explaining it to you and won’t crap up this guy’s thread anymore.
Thanks for the responses guys. I'll take the car out this weekend for some 3rd gear pulls and see how the boost response is and report back. My 2 mile, city street, commute to work each day isn't very conducive to testing, lol. Is there anything in the combo that stands out as a potential cause of the "slow" boost build, other than possibly the turbos are just too big?
On a positive note, I've been playing with the trans brake, and can very easily and quickly build a full 20psi at only 4k rpm. So that gives me hope that at the track I will have full boost for a much greater portion of the run. I don't plan on launching at that level, but at least it will be much closer to peak boost when I first start moving, vs having to build up.
On a positive note, I've been playing with the trans brake, and can very easily and quickly build a full 20psi at only 4k rpm. So that gives me hope that at the track I will have full boost for a much greater portion of the run. I don't plan on launching at that level, but at least it will be much closer to peak boost when I first start moving, vs having to build up.