kijima

What is the application of the motor, I know it's race, but in what application?

In my mind that plays a huge part on getting the right answer.

THUB

iTrader: (5)

I can't speak from personal experience, but the differences would be less than you might expect. Wider ring gaps, than even an extremely high HP drag engine would be used for heat management, maybe a little tighter bearing clearances if its going to be revved higher for improved oiling if it isn't dry-sumped. way wider clearances if it is dry sumped to take advantage of the generally much larger oil pump. Lighter rotating assembly parts could be advantageous if power permits...
The tuning is very different, and your oil cooler and radiator are going to have to be much bigger.
If anybody who's ever actually built and raced on a road course want to chime in I'd love to hear also.

My03evo

iTrader: (1)

Keeping this thread alive.....My SBR shortblock has over 27k miles on it (all within a year's time haha) and has wider bearing clearances/race bearings, and I'm assuming much bigger ring end gaps because it does burn alot of oil but I'm on the highway at a constant 3k-3700k rpm for long periods of time. Either way I'm expecting many more miles to go, granted I don't take it to the track every weekend but high mileage is high mileage for a "loose engine making alot of power/boost

r_ace_r

iTrader: (10)

THUB
generally I agree with all you sad..

But to make this topic more useful could anyone suggest specific engine specs for a purpose built engine?
(e.g. clearances, parts used for a certain power or rev range, or build type like street/drag/track, how long the engine is/was running)..
Please without theories or heard stories, just practice.

THUB

iTrader: (5)

Honestly, I've only built 2 engines. I've just done a ton of reading over the years on topics that applied to this thread. I got my clearance specs from threads I searched here (I honestly can't remember what I assembled my engine to now). I built a 2.4 LR, which , I think, is a fantastic engine for a street car, but not being able to rev as high would limit most high-power cars. I didn't use any super cool coatings or techniques aside from good balancing, because those cost money and I'm a broke ***, but again, I've read about their potential gains.

LCS

iTrader: (9)

I think the drag strip guys build looser engines due the very high output.

I have a Evo 7 mainly for road racing and I built it´s engine with 0,1mm (0,004") piston to wall clearance and OEM clearances on all bearings. It if fails I´ll let you guys know. Until now it´s not burning oil, starts at the first try and revs tight. Not a single noise nor phantom knock.

THUB

iTrader: (5)

That sounds pretty logical. I know F1 engines run such tight clearances that at room temperature the engine is actually seized, while super high output drag cars are ultra loose. For the Evo, though, there isn't a whole lot of difference between OEM spec and too loose to make good oil pressure, so everybody pretty much builds them to very similar spec.

analogEvo

iTrader: (2)

Does this apply to all built blocks? I daily my car and wanted to reach around 450-550 whp (Dynojet).was thinking of a 2.0 or 2.3l build .I would race maybe 3 times a year until the good track is built(road course) then race more but for now it would be a DD.

civicej8

iTrader: (8)

I wanted to basically find out how to prolong a daily driver/built block evo.

i have heard on some built motors going over 80k (buschur) and that sounds very promising.

i would believe that running tighter tolerances on a motor would result in more ring consumption if you would be dailying the car. meaning cold starts, i have heard to counteract this is a block heater. ovcourse it wont stop rings getting worn but it might help.

THUB

iTrader: (5)

Race engines consume oil through the rings because they have a bigger end gap. shrinking that gap would make that stop, but it would make the engine less able to tolerate high power, while doing nothing to prevent wear. Ring wear probably will not be what kills any engine.
Race bearings are made of softer materials in order to resist spinning under high loads. using factory bearings with wider clearances would be a good step in the direction of increasing longevity.

civicej8

iTrader: (8)

thats a good idea right there. i personally have never heard of anyone running oem bearings in a built block. they should have a torque rating for bearings.

so basically the more horsepower you push the faster the bearings wear. got it

1fastblackevo8

How long do you think my buschur 2.1 4g64/63 stage 3 head build would last. I go to the track maybe twice a year and will be running 40psi of boost and its a dd and i do some street racing. Im not real hard on the car and i dont race anything at the light lol.