Picking a New Full Race Stall Speed

[Alky V6]

1130HP at 154MPH weighing i think you said 3100? I do not think its that much.

You have to take the incrementals of that pass into consideration. I wish they had given a 330' mph. The car didn't kick in until halfway between the 330' and the 1/8 marker. A similar pass that was done at the same event is in my sig. With the lead the other guy had on me by the 330' mark, and the amount that I had on him at the finish, you can imagine everyone's expression.

60': 1.666
330': 4.370
330' mph: (not given)
1/8: 6.388
1/8 mph: 122.79
1000': 8.109
1/4: 9.564
1/4 mph: 154.87

Vehicle weight: 3160 w/T76mm turbo. You can call it closer to 3200 lbs after the install of the S510/91mm. That sucker is very heavy.
When I used a DR simulator to simulate the pass, and the incrementals, 1130 hp is what came up as being required to make up for that much lag at the first half of the pass.

 

[baadgn]

You have to take the incrementals of that pass into consideration. I wish they had given a 330' mph. The car didn't kick in until halfway between the 330' and the 1/8 marker. A similar pass that was done at the same event is in my sig. With the lead the other guy had on me by the 330' mark, and the amount that I had on him at the finish, you can imagine everyone's expression.

60': 1.666
330': 4.370
330' mph: (not given)
1/8: 6.388
1/8 mph: 122.79
1000': 8.109
1/4: 9.564
1/4 mph: 154.87

Vehicle weight: 3160 w/T76mm turbo. You can call it closer to 3200 lbs after the install of the S510/91mm. That sucker is very heavy.
When I used a DR simulator to simulate the pass, and the incrementals, 1130 hp is what came up as being required to make up for that much lag at the first half of the pass.

Based on the mph picked up from the 1/8 to the 1/4 its not that far off.
912 hp is what i come up with thats the bad news. The good news is that I KNOW why the car wont accelarate to the 330 put a converter in the car and your life will be simpler.

 

[Alky V6]

Based on the mph picked up from the 1/8 to the 1/4 its not that far off.
912 hp is what i come up with thats the bad news. The good news is that I KNOW why the car wont accelarate to the 330 put a converter in the car and your life will be simpler.

Converter is in the works.
Is the 912 that you came up with a bhp figure or a 'to the ground' figure? Most likely, to the ground.
The 1,130 figure I came up with is bhp or flywheel hp. Most dyno operators will tell you 20% power loss through the drivetrain with an auto trans. More, if a high stall TC (>2200 rpm stall) is involved.

1130 x .80 = 904
Good for you. You're not too far off.

 

[baadgn]

Converter is in the works.
Is the 912 that you came up with a bhp figure or a 'to the ground' figure? Most likely, to the ground.
The 1,130 figure I came up with is bhp or flywheel hp. Most dyno operators will tell you 20% power loss through the drivetrain with an auto trans. More, if a high stall TC (>2200 rpm stall) is involved.

1130 x .80 = 904
Good for you. You're not too far off.

The 912 is bhp,
as a comparison nothing more mine comes in at 1478 bhp, So i do agree that it is bhp if not i would be close to 1800 hp at the motor. I dont think thats possiable.

 

[Alky V6]

The 912 is bhp,
as a comparison nothing more mine comes in at 1478 bhp, So i do agree that it is bhp if not i would be close to 1800 hp at the motor. I dont think thats possiable.

So that means that 'to the ground' hp is 730? With the poor incrementals of that pass and 154 mph at the finish, you're claiming that only 730 hp was needed at the wheels to do this???
What are you using to come up with your hp figures, and how did you factor in the incrementals?

 

[HighPSI]

For comparison sake, I know 803 rwhp has gone 152.93 mph at 3570.

I still can't figure out why you went with such a big turbo when you only plan on running mid 8's with such a small motor Bigger isn't always better.

IMHO: I would leave the convertor alone and trade that turbo in on a billet 4276.

 

[Alky V6]

For comparison sake, I know 803 rwhp has gone 152.93 mph at 3570.

I still can't figure out why you went with such a big turbo when you only plan on running mid 8's with such a small motor Bigger isn't always better.

IMHO: I would leave the convertor alone and trade that turbo in on a billet 4276.

I wanted a turbo that would satisfy, not be a perfect match, but satisfy this present state of the project and handle any future growth of the project.
Ultimately, if funds permit, the plan will be to switch to Stage II heads with a stroker crank, using the same tuning principles I've learned with this Stage I setup, including the tuned manifolding and nitrous oxide injection. The 91mm will fit in very nicely with that combination, and will be very efficient.
I know I've already covered this reasoning more than a few times before. Sorry for boring those that are following this project more closely.

With the Stage II combination, the present TC may work well being brought back into the mix. The increased stroke alone would push the stall while on the nitrous into a more useful range. Though, that would depend on where the new rpm operating range of the engine ends up being. Most likely 1,000+ rpm higher than the Stage I combo.

Is that 803hp a bhp figure or at the ground? Nevermind. I see the rwhp. What's the 3570? Surely not rpm.

I don't think people realize how much horsepower it takes to increase the mph at this level just a couple mph. Let alone, with a poor 1.67 60'.

 

[Alky V6]

Some interesting tid bits of information about the video link I referred to earlier.
That was my last pass during qualifying (first of the qualifying session) at Pinks All Out Bakersfield.
You'll notice that the cars acceleration slowed as I came up along side the other car. I had to slightly back out of the throttle as I was coming up along side him due to the car drifting towards him. You can barely make out the drifting in the video. After getting back to the pits, one of my highly trained pit crewmen noticed a lot of oil in the back of the engine bay. It turns out, oil had coated the whole underside of the car, and there were oil spots on the tread of the rear tires. The cam plug had blown out on that pass due to crankcase pressure. How much HP was I losing due to that much crankcase pressure?

Install a safety retainer over your cam plug!

 

[HighPSI]

Is that 803hp a bhp figure or at the ground? Nevermind. I see the rwhp. What's the 3570? Surely not rpm.

3570 is the weight of the car in pounds.

 

[bison]

It turns out, oil had coated the whole underside of the car, and there were oil spots on the tread of the rear tires. The cam plug had blown out on that pass due to crankcase pressure. How much HP was I losing due to that much crankcase pressure?

Install a safety retainer over your cam plug!

Id consider myself lucky if i didnt wreck and wouldnt be too worried about how much hp i was losing due to crankcase pressure. Id look at the cam plug bore a little closer. It should take a lot of pressure to blow it out and id think you would have noticed symptoms on prior passes that you had excessive crank case pressure. I had a piston fail at 33psi and 5800 rpm and still didnt blow out the cam plug. I did feel it and saw an oily vapor around the cowl area but it all came out the breathers.

 

[baadgn]

So that means that 'to the ground' hp is 730? With the poor incrementals of that pass and 154 mph at the finish, you're claiming that only 730 hp was needed at the wheels to do this???
What are you using to come up with your hp figures, and how did you factor in the incrementals?

Don, let me ask you this what does your hp calculator come up with for my car 5.11@ 142 1/8 7.97@ 175 1/4 1.34 60 ft in a 3465 # car.

 

[Alky V6]

Id consider myself lucky if i didnt wreck and wouldnt be too worried about how much hp i was losing due to crankcase pressure. Id look at the cam plug bore a little closer. It should take a lot of pressure to blow it out and id think you would have noticed symptoms on prior passes that you had excessive crank case pressure. I had a piston fail at 33psi and 5800 rpm and still didnt blow out the cam plug. I did feel it and saw an oily vapor around the cowl area but it all came out the breathers.

You're right. There were other symptoms prior to that. I was using a large lip front crankshaft seal. The kind that is self centering, and on one pass the crankcase pressure popped/flipped the lip outward. After that, I switched to a short lip seal and modified the timing cover with a removable seal retainer housing so that I could change the seal without removing the timing cover.
A leakdown test showed 1-2% leakage, so it's not a hole in the piston. I'm sure it's ring blowby under dynamic operation, and that'll be taken care of during the next PMing of the motor.

 

[Alky V6]

Don, let me ask you this what does your hp calculator come up with for my car 5.11@ 142 1/8 7.97@ 175 1/4 1.34 60 ft in a 3465 # car.

I'd love to drag sim your car, but I don't think you have a clue as to how much information the sim that I use requires. It's not just a 'plug in a few numbers and pop out a result' type of sim.

If you're serious about me doing this, I can email you a data form for you to fill out.

 

[S2V6RACER]

Don, I thought I noticed you are running a dry sump system. I assume you are typically running the engine under vacuum. I'm not running a vacuum pump and do log crankcase pressure and I am only seeing + .4 to .6 inches of mercury (.29psi) running the engine around 35# of boost. What kind of pressure were you seeing when this happened?

 

[Alky V6]

Don, I thought I noticed you are running a dry sump system. I assume you are typically running the engine under vacuum. I'm not running a vacuum pump and do log crankcase pressure and I am only seeing + .4 to .6 inches of mercury (.29psi) running the engine around 35# of boost. What kind of pressure were you seeing when this happened?

Yes, I am running a 3 stage drysump. I'm also running an early design 4 vane Moroso crankcase pump. The one breather on the driver's side that I was using was not blocked, though. I have since installed the passenger side breather that will exhaust crankcase pressure, but will not allow air into the engine. The passenger side breather is on the same side as the fitting to the crankcase pump. By not allowing the passenger side breather to let air into the engine, it forces fresh air to flow to the vacuum pump from the driver's side of the engine, doing a better job of flushing the engine of methanol blowby vapors.
Methanol blowby has a lot of fuel, and especially water vapor content, and keeping the driver's side breather open like that keeps the engine oil in very good shape compared to not allowing fresh air to circulate. Instead of changing the oil after one testing session, I can go for multiple sessions with the same oil. In fact, I just changed the oil after a long period of testing in the shop and at the track multiple times, and I could have left that oil in there for longer by the way it looked. No milky or foggy look to it.
The real secret is to make sure you get the engine and oil up to at least 160 degrees F to boil off the fuel and water content that collects. Getting up to temp and with the circulating air, the oil stays in great shape.
Another thing. You must use an oil that is methanol compatible.

 

[Alky V6]

This is the first overhauling of this engine that showed signs of blowby like this. I'm just chalking it up to a problem with the break-in of the rings and I'll take care of it during the next PMing of the engine, which will probably happen before the end of the year. She needs new piston pins for sure. Last time I had her apart, most of them had a slight bend. Thick walled Ti pins just can't take it.

 

[Dusty Bradford]

I don't think people realize how much horsepower it takes to increase the mph at this level just a couple mph. Let alone, with a poor 1.67 60'.

Don. Are you getting this from the sim or real world experience. From reading some of these posts I get the feeling your saying if you were to have a 1.30 60' you would expect more mph???

I have found from very little 1/4 racing that I do, the 1/4 mile mph will not change due to the 60' or the 330'. Your 1/8 mile mph will be lower if the car spins or is slow getting off the line but the 1/4 mph is very consistent. I ran 182-185 on all my 1/4 passes, some spinning, some easing it out of the hole and others on good passes.

 

[HighPSI]

I'd love to drag sim your car, but I don't think you have a clue as to how much information the sim that I use requires. It's not just a 'plug in a few numbers and pop out a result' type of sim.

If you're serious about me doing this, I can email you a data form for you to fill out.

Don, could you send me the data form on your car? The additional information you inputted still can't account for the 1130-730=400hp diference.

BTW: Would you be interested in doing my taxes :biggrin:

 

[Alky V6]

Don. Are you getting this from the sim or real world experience. From reading some of these posts I get the feeling your saying if you were to have a 1.30 60' you would expect more mph???

I have found from very little 1/4 racing that I do, the 1/4 mile mph will not change due to the 60' or the 330'. Your 1/8 mile mph will be lower if the car spins or is slow getting off the line but the 1/4 mph is very consistent. I ran 182-185 on all my 1/4 passes, some spinning, some easing it out of the hole and others on good passes.

You're correct. I do expect more mph with a proper 60'. Not much, though. I don't expect to see over 157 mph with the type of first half that I'm shooting for. That would be an increase of just over 2 mph. The 1/8 mile should be more than just an increase of 2 mph.
This is what the sim is showing me, since I have no real world experience to test the sim against.
Not yet, anyway.

 

[Alky V6]

Don, could you send me the data form on your car? The additional information you inputted still can't account for the 1130-730=400hp diference.

BTW: Would you be interested in doing my taxes :biggrin:

Are you using Performance Trend's Drag Analyzer Pro 2.0?
BTW, people can download a version from Performance Trend's website and use it for a trial period for free. I can't recall if all the features can be used or not in the trial mode. But you can get an idea of all the input that's necessary.