hi guys,

my question is:

what is the max bhp of std turbo?

now, forget about strokers, nitrous, race fuel, nitrous on the intercooler, etc. just plain pump gas.

on another evo forum in the uk, i've heard people assert the max bhp of the std turbo is 400bhp. and if you look at the dyno results of these evos in the uk, you'll find this seems to be quite true. in fact many highly modified evos are only about the 380 mark or less.

now in the uk, these are jap spec cars which probably have more power than the usa evo 8, and they have higher octane pump gas, and the std boost of say an evo 6 is only 1 bar compared to the rather high boost of the usa evo 8.

i'm not trying to stir up trouble or anything, i just want people to be realistic about things. i've seen many dyno results in the uk for evo 4/5/6/7/8 and nobody with a std turbo is pushing more than 400bhp! not even more than 380 as best i can recall.

let me know what you guys think.

brandon

 

Actually if you do some research you will find that your premium pump fuel is lower octane than North American permium pump fuel.

Here is a quote about British fuel from http://216.239.41.104/search?q=cache...n&ie=UTF-8</a>

"The British Standard Specification for 4-star (premium) petrol is a minimum of 97 RON/86 MON though it is usually marketed at 98 RON."

Taking those numbers you will see that British premium fuel is equivelent to 91.5 Octane in North America (97 + 86)/2 = 91.5

All fuel sold in the US is sold under the AKI (anti knock index) method of (RON + MON)/2.

The other factor is that you are probably using a dyno dynamics dynometer, and they are known to be notoriously low reading compared to an inertial dyno or when compared to "real world" calculations of HP based on a vehicles weight and 1/4 mile elapsed time and trap speed. If you are using a dyno dynamics dynometer apply a correction factor of aprox 1.3 to get what you would read on an inertial dynometer, or on a "dynapack" style load bank type of dyno.

If you take into acount that american premium pump fuel is 94 octane (AKI) and your premium is the equivelent of our mid grade fuel at 91.5 octane (AKI) plus the use of dynos that read low you can see where the differences are comming from. So far we have seen 360 HP at the wheels (aprox 415 HP at the crank shaft) on pump gas with simple bolt on parts on the stock turbo, stock block, no head work other than cams. That would be around 275 HP to 280 HP at the wheels on a dyno dynamics dynometer.

Keith

 

there are too many factors to give a specific number for hp on pump gas. in the case of the evo the turbo is the limitation. once you get near 400hp it starts blowing alot of hot air. we have made over 550hp on hondas with pump gas. with a bigger turbo i dont see why you couldnt make that kind of power from an evo on pump gas.

 

It the supporting parts not the turbo that make the difference:
1) FMIC
2) Stand Alone EMS
3) Bigger Injectors
4) Fuel Pump
5) Turbo Back Exhaust...

 

just because you have all that supporting stuff dosnt mean you can crank out 500 hp from any given turbo. the turbo will max out, the evo turbo dosnt really have much headroom.

step up to something with more efficent design and make some real power. there is NO reason it should take the ammount of boost it takes in a stock turbo evo to produce the power. we are making 300hp with as little as 8psi on the hondas we do. at 20psi we are close to 500.

 

keith,

thanks for the info regarding octane ratings. i don't know much about that but read once before about the differing standards. thanks for clearing it up.

in regards to the differences in dynos, i was not quoting wheel horsepower i was saying 400 bhp at the fly. granted this is calculated from an atw figure, but the flywheel estimate should be pretty accurate given that they have dyno'd many std cars so they have a good benchmark.

so it does not change the fact that i have seen a lot of dyno results in the uk, and cars with everything modifed but the turbo, they normally achieve around 380-400 bhp.

you mentioned the octane difference, and it seems that would help. i just think people should be realistic about what the results of each mod should be. for instance:

271 bhp base evo 8

exhaust and air intake: 5-20 bhp
ecu mapping and boost at ~ 1.5 bar: 30-70 bhp
cams: 10-30 bhp
intercooler: 0-10 bhp

so do you think these estimates are reasonable?

what this shows me is that it would be very difficult to reach 400 bhp with an evo and std turbo. what are your thoughts?

brandon

 

You can't compare psi numbers from two totally different applications, it is comparing apples to oranges. Just because a honda makes 300hp at 8psi does not mean that the same is possible on the Evo.

 

psi means nuthing when it comes to HP, its about flow. pressure is a resistance to flow. if you can flow more at a lower psi then you will make more power. open up the head, open up the exhaust, open up the intake and you increase the flow. more flow means you need a bigger, more efficent turbo. a more efficent turbo will flow more at lower boost levels, this means less heat and faster spool.

 

Buschur seems to have hit the wall at 440-445bhp on the stock turbo. They've moved on to larger turbos as have most of the tuners in the US.