95ONE

Or you can take a simpler approach. Stock Power without turbo is around 125-135hp@wheels. Lets be optimistic and say 135. - interesting as a MAP car, I can now remove charge pipes and actually dyno this. - Moving forward. Lets say head work, cams, Header, Intake and exhaust work, and tuning bring that number to 180. 608/180 = 3.36 times more power. So... with a turbo charger system working at 100%efficiency (Not attainable without added charge air cooling tricks) He would need 3.36 X 14.7 = 49.4lbs of boost.
Or say it actually makes 210whp without boost. - VERY optimistic. Gives you an equation of (605/210)14.7= 42lbs of boost.

I have seen such boost levels. Could ST have run that in his boosted run. Absolutely. Did he actually do it? I don't think many will be satisfied until 944fest When he gives his best without excuses.

ehall

umm...wow.

Lorax

hahahahahahaha

vt951

Ok, so it's looking to me like it's not impossible for the 602 rwhp claim to be true. So, I guess the real challenge that has to be overcome to achieve that level of power is to beef up the plumbing and engine internals to be able to handle 40+ psi of boost, to cool the air, and work the intake and head to increase the VE. Sounds like fuel supply is not an issue.

What kind of boost did the old Indy cars run? Weren't they around 2.5L and 40 psi boost? I think they made close to 1000 hp, and that was 30 years ago. Not sure what rpm they made that power at though.

Lorax

How much power did he gain just by switching to dry sump? Wasn't it a pretty large amount?

toddk911

LOL!!!!!!!!!!!! New bumper sticker!


I know ST was running a ton of boost in his build up runs whee he wput down 550+; 30-40psi

His issue, and not to speak for ST, was head lift not detonation, etc.

If anyone wants to break down the numbers:

2.5L = 600whp?

Supras 3.0L = 1,000whp???


So yes, I think 600whp is very attainable from 2.5L.

toddk911

Yes, they ran 40psi in race trim and 50psi in qualifying trim. It was all based on running about 90% Toluene.

Then Indy eliminated the allowance of Toluene and the super high boost stopped.

As has been discussed on RL over and over, in theory, boost does not blow motors/head gaskets.....Heat does!

Detonation doesn't blow HG. It's the heat that causes the detonation; i.e. heat is the source of the problems.

Read about the Buick GNX guys and how they swear by water/meth injection and just like the Supra guys they run 25-30psi all day long.

blown 944

yea I was being a little simple there. When I was building race engines we were worried more about the "total" flow of the runner not just the peak flow ie; low lift numbers and the average across the board. This is why I threw out the velocity statement. Kind of why I would not recommend a set of BIG Chiefs for a 454 (unless they were running a ton of boost or nitrous and high rpms). There are better suited headflows for torque and/or high rpm HP.

This gives me reason to believe ST's numbers at ~ mid to late 30psi and why I don't totally go along with multiplying the stock HP/TQ numbers.

Consider this: the factory HP that these comparisons are being based apon are not really tuned for top VE. Otherwise they would be running 14 or 15:1 compression, big cams and wild headflows. ST's combo was modified (esp in the head area) from a stock application so the multiplying factors IMO can't be fully used. If you took ST's head/cam and threw it on a stock NA setup I would venture to say it would actually go down in HP.

I think the comparison would work for an unmodified head,cam etc.. Just not a highly modified setup.

Tms951

I thought tool said he was running 28psi? I would love to see one of these cars run 35+ psi. I don't know how you would hold the head on. I bet it could even pull head studs out of the soft aluminium block.

Remember the F1 engines we are talking about running 40+ psi were developed on a huge budget by a team of real professionals. And the heads were WELDED to the block.

toddk911

You may be right. i know it was either 30psi or really close to it. And his issue was head lift.

Great point about the F1 motors. Although, is the block/head on the Supra's iron or aluminum??

blown 944

ha I have ran 35 psi. No it didn't pull studs. Yes it did push the HG (it was a year old that was showing deterioration anyway). I ran it pretty hard for about an hr with many runs to 35 psi. Here is a vid of ~29 psi (what I was driving around running) unfortunately the camera battery died before I really cranked it up
http://www.youtube.com/watch?v=dxPSK...e=channel_page

toddk911

Duh! I totally forgot about your E85 super boost experience.

Well, there you go with real world experience that if the octane and tuning are there, the motor will handle a TON of boost.

I have always thought the key is EGT. If they are maintained in safe levels, just keep turning up the boost until they rise and then dial it back some.

I think this is proven as many on here with mostly stock motors and small stock turbos have run 20-22psi on pump with no issues for years since they have spot on tuning and safe a/f and egt.

Lorax

cylinder pressure or more simply put how much power you are generating is what causes head lift, not how much boost you are running

porshhhh951

I would believe the same thing. I think ST was creating alot more pressure and making alot more power flowing much more air even though he was running similar/less boost pressure.

toddk911

Isn't the amount of boost/compression a direct proponent to head pressure?

I think a large motor easily making 500hp would have a LOT less head/cyl pressure than a smaller motor making a lot of head/cyl pressure and only making 300hp.

I.e.

Large motor @ 9:1 = 500hp

Small motor @ 12:1 = 300hp

Which one is going to be more likely to have head lift?

In that example hp would not be the issue, head pressure/cyl compression is.