max hp on k04s?

[ant.m]

Hello, sorry if im bringing up the dead with this thread. But I just wanted to ask what is a good estimate for max hp/tq on ko4s? as im stuck in either purchasing some rs6 turbos, or some K04s

[jolio1994]

91oct? 93oct? e85? meth?

supporting mods? I think there are a lot of variables out there, but I'd say a tad over 500-530hp at the crank on a Dynojet? Unless big things been happening since I've been away for 7 years... lol

[ant.m]

91oct? 93oct? e85? meth?

supporting mods? I think there are a lot of variables out there, but I'd say a tad over 500-530hp at the crank on a Dynojet? Unless big things been happening since I've been away for 7 years... lol

well that is true. but I was thinking of running e85 and/or 93 octane. I would run supporting mods to get the most out of them.

[S4James]

straight k04s will make 500hp at crank, k04 hybrids can make around 550hp.

[CELison]

K04s on E is the best setup for this platform on a stock block IMO.

[Groto]

Mine has k04s and is tuned for 91, yet all we have up here is 93. :/

[SauerkrautPower]

I spoke to Mike at Wicked Motorsports in Van Nuys, CA and he said that if the block is going to be stock its best to use K04s because they are going to spool faster and can make around 450hp to the wheels on 91. SRM K24 RS6 hybrids spool too long but will be better for straight line acceleration.

I personally am building my B5 S4 for mountain road cruising and the mid range torque would be better with K04s versus waiting for the Rs6 turbos to spool.

Never had experience with both. This is solely based off of research and youtube videos lol.

Can someone chime in if the ball bearing SRM turbos spool as fast as k04s?

[CELison]

Mike really knows his shit, he’s been in the b5 game since the beginning and has built awesome cars. But 450whp on K04s and 91 isn’t happening.

[SauerkrautPower]

Mike really knows his shit, he’s been in the b5 game since the beginning and has built awesome cars. But 450whp on K04s and 91 isn’t happening.

Yes Mikes shop caught my attention when I read that article on superstreet of that time attack built b5 s4 with gt28rs turbos pushing 700hp on race fuel.

I mean if the motor is being pulled might as well change the rods and do a full e85 build if its not a daily driver. Its not worth spending over 12k in labor and parts for an extra 80hp from the stock k03s to k04s to limit it with the stock rods and a 91 tune.

So would 400hp to the wheels be realistic with k04s on a 91?

[CELison]

Eh, 380ish probably on a mustang. E85 can get you 450 out of K04s. 91 is just dog piss. Or run W/M.

[Protection]

Eh, 380ish probably on a mustang. E85 can get you 450 out of K04s. 91 is just dog piss. Or run W/M.

Could you expect to do any better on E85 with rods and heads w/ Supertech springs? Or is efficiency maxed out on the turbo? Asking for a friend ;)


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[cjt671]

Could you expect to do any better on E85 with rods and heads w/ Supertech springs? Or is efficiency maxed out on the turbo? Asking for a friend ;)


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My E85 K04 car made 490 and 480 in the Cali summer heat on the same mustang dyno on different days and with different tunes but hey who knows whats what when it comes dyno numbers


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[Mocke]

450whp is not too hard to achieve on E85 no matter which dyno is used.
Not related to your car cjt671, but in general - Mustang can be tricky without baseline. Seen some crazy numbers for way too slow cars in reality.
Our pjk04 cars on E85 tend to run low 7sec 100-200 and low 8sec 60-130mph.
Logger estimated to 450-460whp.
Low grade fuel like 91, you should be happy for anything over 350whp frankly.

[landfill]

On rs6 k04’s you can achieve over
500whp.

[cjt671]

450whp is not too hard to achieve on E85 no matter which dyno is used.
Not related to your car cjt671, but in general - Mustang can be tricky without baseline. Seen some crazy numbers for way too slow cars in reality.
Our pjk04 cars on E85 tend to run low 7sec 100-200 and low 8sec 60-130mph.
Logger estimated to 450-460whp.
Low grade fuel like 91, you should be happy for anything over 350whp frankly.

Agreed, dyno number validity in general are hard to trust. Great tuning tools and good to measure how well you are progressing if able to use the same one.

My car in reality is 400-450 range on e85
Definitely under 380 on pump gas


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[ant.m]

Thank you everyone for the replies . Keep the info coming as I would love to know more. Any info helps :))).

[AudiSportB5S4]

More important just just HP figures alone is you need to determine where you personally enjoy the car the most... I had RS4 K04s in my car for 11 years and over last (18-19) winter switched to RS6 K04s while the engine was out for some maintenance and there are certainly some trade offs especially on pump gas (93 octane) that you have to determine if you are comfortable with them or not. For example - I used to love pulling off 1-2s, 2-3s in my car and then I'd shut it down. Wasn't really into taking the car too far beyond 100mph usually. Now with the RS6s I feel I need a longer runway to really enjoy them. It's not like the car lost all power down low, but generally speaking as you go larger on the turbo size you're pushing your fun zone a little bit to the right.

My personal gripe with E85 is availability of it.. I like to drive my car too much to have to worry about finding gas stations that carry E85. There is a ton of timing to be had with it, so it depends what sacrifices you're willing to make. I just think you'll see less and less E85 in the future, honestly. Unfortunately that wasn't a trend that really stuck mass market.