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RicerSchnitzzzle
 
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Turbo HP physics question

Okay, not really shark related but I think we have some pretty darn smart turbo experts here so it's my best chance to get a good answer.

I frequent a local car club board. It's open to all types of cars and has pretty cool GTGs. Nice open minded group. However there is a small click of ricers that make outrageous turbo claims.

My question is this. How can you get 450RWHP out of a 1.8l Honda @22psi that's only 170RWHP N/A? (and 170RWHP is BUILT for a Honda!)

I know to find out power at a given PSI you can use this formula to get part way there.
New power = [ ( NA power / 14.7 ) * amount of boost ] + NA power.
Of course that doesn't factor in friction, heat, manifold limitations etc.. It will always be lower than the number you get with that formula.

So what is the magic sauce these guys have to get 450HP? Did the G8 summit declare that imports can ignore Boyle's law? I know some use meth injection which allows more aggressive timing and adds a little to the combustible fuel in the cylinders, but even aggressive timing is less than stock N/A timing limits and therefor leaving a little power on the table. And water injection is the same deal with out the aide of extra fuel. These are the same guys who think a larger turbo running at the same psi as a smaller one will make more power on the same car...because it flows more. I thought psi in a dynamic system was a measure of the resistance to flow, therefor 2 different turbos on the same car at the same psi should move the same air mass.

So am I correct that you roughly double power of the NA engine with each increase of 1 bar? And there is no way a 1.8L Honda could make 350RWHP with out hitting over 30psi? Boyle's law says that PSI is directly proportional to temp and air mass. There for if temp goes up, air mass must go down for a given PSI. Correct?

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'81 Euro 'S' 928 5-Speed 5.0L Hybrid "Ricerschnitzzzle" Wish list: RollBar, New Helmet and driving lessons
Wishes Done: Body kit, seats, No cat, Headers, X, Afterburners, 3" exhaust, short shifter , 17" TT Rims, 250HP N2O, MSD ignition w/retard+rev limit, MSD billet distributor, Accel Coil. 5.0L block, ported heads, JE race springs + .503 "S+" cams

Last edited by N2O-SHARK; 08-03-2008 at 10:14 AM..
Old 08-03-2008, 10:10 AM
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Quote:
Originally Posted by N2O-SHARK View Post
So what is the magic sauce these guys have to get 450HP?

Probably weed. Just a guess. And optimism. Lots of optimism.


So am I correct that you roughly double power of the NA engine with each increase of 1 bar? And there is no way a 1.8L Honda could make 350RWHP with out hitting over 30psi? Boyle's law says that PSI is directly proportional to temp and air mass. There for if temp goes up, air mass must go down for a given PSI. Correct?
You can deal with all the complications. For 450hp at the wheel you need 300 at the crank N/A, (167hp per liter). Chances are slim, just like the old 8 ball used to say.
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Last edited by Mule; 08-03-2008 at 12:51 PM..
Old 08-03-2008, 12:49 PM
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with that little PSI imo they have a snowballs chance in hell.

With my build I am starting with 310 RWHP and at one bar will be happy to see 650RWHP, but I am also loosing a massive restriction in the intake and adding drysump :P
Old 08-03-2008, 12:52 PM
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Quote:
Originally Posted by lizard928s View Post
with that little PSI imo they have a snowballs chance in hell.

With my build I am starting with 310 RWHP and at one bar will be happy to see 650RWHP, but I am also loosing a massive restriction in the intake and adding drysump :P
Mathematicly impossible. At one bar the most you would see is double. Someone can correct me if I'm wrong however I'd like to see the math.
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Old 08-03-2008, 01:16 PM
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Abby,

In the latter part of that sentance you see I also state that I am loosing a large intake restriction, and converting to a FULL drysump.

The intake restriction will give me a fair bump in power N/A and then going to drysump will give better sealing of the rings as well as no oil sitting there to slow the crank down when it hits it.

As well at 310RWHP, (last time on a dyno) I still didnt have the AFR perfect, so there was abit more to be gained there.

As well I said I will be happy to see that, meaning that is my goal but I wont be completely disappointed if I am abit shy.
Old 08-03-2008, 01:50 PM
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Originally Posted by lizard928s View Post
Abby,

In the latter part of that sentance you see I also state that I am loosing a large intake restriction, and converting to a FULL drysump.

The intake restriction will give me a fair bump in power N/A and then going to drysump will give better sealing of the rings as well as no oil sitting there to slow the crank down when it hits it.

As well at 310RWHP, (last time on a dyno) I still didnt have the AFR perfect, so there was abit more to be gained there.

As well I said I will be happy to see that, meaning that is my goal but I wont be completely disappointed if I am abit shy.
What model car? 310rwhp sounds high to start with. For the cost of the dry sump you could install a big stuff or a F.A.S.T and have a lot better chance of making that much power. If it's pre '87 I don't see how you can accomplish this with FI.
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Old 08-03-2008, 02:01 PM
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Mule, chassis is 1981, engine is an 1986.

As to the cost of the drysump, the cost of the pulley and pump was the big expenses, I have modified a factory oil pump for it.

I pulled 310RWHP with not the most efficent exhaust 2.25" crush bent, with H tube. completely stock internals.
An agressive ign map, with standalone EFI running EDIS. running a .045" gap with no issues. Massive spark on that too. And 320 RW FT LBS on that as well.

Good spark, and a better EFI system can do wonders for power.

Porken has 312RWHP on the 86 engine with factory EFI.

As well imo the 85/86 engines are less detonation prone than the S4 engines so you can feed them much more spark.

I am not wanting NOS on my engine, and I dont want SC centrifigal or otherwise. I want turbos, and have custom made manifolds and all the needed pieces for them.
They are mounted at the front of the engine, and all componants will be getting a special ceramic treatment.
Old 08-03-2008, 02:15 PM
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Enzo
Formula for Horsepower
Old 08-03-2008, 02:49 PM
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Quote:
Originally Posted by lizard928s View Post
Mule, chassis is 1981, engine is an 1986.

As to the cost of the drysump, the cost of the pulley and pump was the big expenses, I have modified a factory oil pump for it.

I pulled 310RWHP with not the most efficent exhaust 2.25" crush bent, with H tube. completely stock internals.
An agressive ign map, with standalone EFI running EDIS. running a .045" gap with no issues. Massive spark on that too. And 320 RW FT LBS on that as well.

Good spark, and a better EFI system can do wonders for power.

Porken has 312RWHP on the 86 engine with factory EFI.

As well imo the 85/86 engines are less detonation prone than the S4 engines so you can feed them much more spark.

I am not wanting NOS on my engine, and I dont want SC centrifigal or otherwise. I want turbos, and have custom made manifolds and all the needed pieces for them.
They are mounted at the front of the engine, and all componants will be getting a special ceramic treatment.
Are you talking about Ford edis fuel injection?
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Old 08-03-2008, 03:36 PM
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Ford EDIS has nothing to do with fuel injection.

EDIS stands for Electronic Distributorless Ign System.

But yes, I am using EDIS -8 with a 36-1 trigger wheel.

For the boosted engine I am not sure if I will stay with EDIS, or if I will go to full COP.
Old 08-03-2008, 03:53 PM
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RicerSchnitzzzle
 
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FOund some great reading on turbo physics. Pretty much sums up what I thought. It's all based off what the engine's NA volumetric efficiency is. After that you see that you can never exceed a doubling for each 1 bar increase when you factor in the rest of the variables.

http://www.turbobygarrett.com/turbob...esel_tech.html

Shows pretty much what I thought and it's from the garret website with all variables accounted for. They come no where close to doubling power per 14.7 psi increase. They start with 275RWHP and add another 150RWHP with 19.8psi. Crunch any numbers in you like and you'll never get more than a doubling per 14.7psi. That's the cap.

Note the last example. They start with 275RWHP and add 350 more. It takes 36.1psi. 36.1psi divided by 14.7 is 2.455, multiply that by NA power and you get 675hp. 275+350=625, a loss of 50HP over the double rule. Again you can't get more than a doubling of NA power per 1 bar above ATM pressure. I still think folks get confuised because the have otehr mods done at the same time as the turbo, exhaust, porting, different cams,larger valves etc.. I think they dont realise what the new NA baseline is.

They also have a great read on the main page..turbo 101, 20 and 301. Warning, your head may hurt a bit by page 3.

http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech101.html
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Wishes Done: Body kit, seats, No cat, Headers, X, Afterburners, 3" exhaust, short shifter , 17" TT Rims, 250HP N2O, MSD ignition w/retard+rev limit, MSD billet distributor, Accel Coil. 5.0L block, ported heads, JE race springs + .503 "S+" cams
Old 08-03-2008, 06:09 PM
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Taken from Hurk-Kuhns signature

"Kuhn Performance Technologies, LLC
Big Gun: 1988 928S4 Twin Turbo, 5-SPD/LSD 572 RWHP, 579 RW ft-lbs, 12 psig manifold pressure. Stock Internals, 93 octane."

if you claim most S4s put down 260 at the wheels that is more than DOUBLE with less than one bar. If he managed to put down 300 at the wheels on this engine before hand, if he cranked it up another 3 PSI I have no doubt he would gain another 28RWHP meaning worst case he would be having a true doubling of the power.

Garrett has that information on there website because they have to have lower claims, if they make big claims or there calculator give very generous information it could lead to a lawsuit.

As well I made 310 RWHP with 87 octane, With boost I will be running 94 and have a much higher threshold.

Last edited by lizard928s; 08-03-2008 at 06:46 PM..
Old 08-03-2008, 06:24 PM
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Another point, I personnally have seen very well engineered turbo setups produce MORE than double the NA HP at one bar of boost.

But there are alot of variables to go over to be able to get it there. In some turbo setups they actually are able to have colder air entering the engine with the turbo than NA which gives abit more power as well.

Once all is said and done with my turbo project I will post numbers and see how well my setup works. All I want to show is that it is entirely possible to get more than double the HP out of 1 bar.
Old 08-03-2008, 06:33 PM
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RicerSchnitzzzle
 
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I'm with you on the double per 1bar, what I'm going against is the 1.8L honda with 150RWHP NA that claims 450RWHP with 22psi boost. Just don't see it.
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Old 08-03-2008, 07:21 PM
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Quote:
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I'm with you on the double per 1bar, what I'm going against is the 1.8L honda with 150RWHP NA that claims 450RWHP with 22psi boost. Just don't see it.
Only way he could is with NOS, and having a MUCH MUCH cooler intake charge with say the use of dry ice.
Old 08-03-2008, 07:46 PM
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Ford EDIS has nothing to do with fuel injection.

EDIS stands for Electronic Distributorless Ign System.

But yes, I am using EDIS -8 with a 36-1 trigger wheel.

For the boosted engine I am not sure if I will stay with EDIS, or if I will go to full COP.
Whose fuel injection system are you using?
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Old 08-03-2008, 08:13 PM
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Taken from Hurk-Kuhns signature

"Kuhn Performance Technologies, LLC
Big Gun: 1988 928S4 Twin Turbo, 5-SPD/LSD 572 RWHP, 579 RW ft-lbs, 12 psig manifold pressure. Stock Internals, 93 octane."

if you claim most S4s put down 260 at the wheels that is more than DOUBLE with less than one bar. If he managed to put down 300 at the wheels on this engine before hand, if he cranked it up another 3 PSI I have no doubt he would gain another 28RWHP meaning worst case he would be having a true doubling of the power.

Garrett has that information on there website because they have to have lower claims, if they make big claims or there calculator give very generous information it could lead to a lawsuit.

As well I made 310 RWHP with 87 octane, With boost I will be running 94 and have a much higher threshold.
So you make 310 on regular with a collapsed exhaust pipe? So fix the pipe & switch to premium and what, 350?
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Old 08-03-2008, 08:18 PM
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Quote:
Originally Posted by lizard928s View Post
Taken from Hurk-Kuhns signature

"Kuhn Performance Technologies, LLC
Big Gun: 1988 928S4 Twin Turbo, 5-SPD/LSD 572 RWHP, 579 RW ft-lbs, 12 psig manifold pressure. Stock Internals, 93 octane."

if you claim most S4s put down 260 at the wheels that is more than DOUBLE with less than one bar. If he managed to put down 300 at the wheels on this engine before hand, if he cranked it up another 3 PSI I have no doubt he would gain another 28RWHP meaning worst case he would be having a true doubling of the power.

Garrett has that information on there website because they have to have lower claims, if they make big claims or there calculator give very generous information it could lead to a lawsuit.

As well I made 310 RWHP with 87 octane, With boost I will be running 94 and have a much higher threshold.
So John would need to be barely above 300. An S4 with enhancenents to induction, exhaust and custom programming (on premium) is much closer to that than you are with a bent exhaust pipe on regular. I promise.
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Old 08-03-2008, 08:26 PM
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It all depends on the dynamometer as well. The units which use a user defined correction factor have a strange way of bringing larger numbers back to the table.

There was a case where I was put under fire for using Dynojet's STD correction factor. A competitor had used a Dynacom and had claimed the car was at something like 540 WHP. The competitor then went back (after I released my numbers, they were larger you see) and "had the dynojet correction factor applied" to the same pull (they never even re-dynoed the car, just opened the old file and had positive correction applied) and was running around claiming 590 some off WHP on the same boost. The owner of that car was boasting the 590 some odd HP in his signature and acting like it made those numbers on a Dynojet machine. The best part was when they went back to redyno the same car and the shop had installed a dynojet. That car was run on the dynojet machine (they said it was down 1.5 psig) and the car just broke 500 WHP with STD correction. So if the 596 was correct, then the car would have lost a whopping 90 HP by being down just two psig. Not possible on any decent state of tune.

There is a lot of hot air surrounding dyno numbers. I have another story on numbers spit out by a Dyno Dynamics...those results can be fixed as well. I saw it done with my own two eyes and had the dyno operator tell me he had applied an additional 20% correction to the numbers after I asked him why the car I had built barely made the same WHP on another dyno when there was 2 psig more boost applied. His exact words to me..."People were *****ing about the low numbers that day so I turned the correction factor up".

As much as people bash dynojet, I will say that the operator cannot reset the correction factors...you may only select between uncorrected, SAE and STD corrections. The only other way to trick it out would be to place the temp sensor in an area where it is warmer, more humid and lower pressure...that could skew the results. But there is no magic place to tell it "apply 10% more today because the people are pissed off".

In the end it doesn't really matter...is the car fast, does it perform, does it do what it is supposed to do? People get way too hung up on dyno results. And remember, a peak dyno number means nothing if you have a powerband that is narrow.
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Kuhn Performance Technologies, LLC
Big Gun: 1988 928S4 Twin Turbo, 5-SPD/LSD 572 RWHP, 579 RW ft-lbs, 12 psig manifold pressure. Stock Internals, 93 octane.
Little Gun: 1981 928 Competition Package Twin Turbo, 375 RWHP, 415 RW ft-lbs, 10psig manifold pressure. Nikasil Block, JE2618 Pistons, 93 octane.

Last edited by Herr-Kuhn; 08-04-2008 at 03:13 AM..
Old 08-04-2008, 03:10 AM
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RicerSchnitzzzle
 
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^That's why I stick to my Gtech for tuning. It may give you junk for HP and torque numbers if you don't know your weight but it's 1/4 and 0-60 times are pretty spot on. Those are the real numbers that matter. No one raced a Dyno on the street or track... I went to the local dump to get weighed with a 1/2 tank of gas. Get's me pretty close.

I have found my Gtech pretty consistant in it's results. It doesn't account for drag, so it's RWHP Numbers will be lower than a dyno by 25-40hp @70mph depending on your drag coefficient. On a pre S4 it's about 29HP @70mph. I plan on using it to call some punks out at our next GTG.
Hmm.. now what's the drag coefficient of a hand with a huge wing, neon and a 8" round fart can?

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Wishes Done: Body kit, seats, No cat, Headers, X, Afterburners, 3" exhaust, short shifter , 17" TT Rims, 250HP N2O, MSD ignition w/retard+rev limit, MSD billet distributor, Accel Coil. 5.0L block, ported heads, JE race springs + .503 "S+" cams
Old 08-04-2008, 07:12 AM
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