Boosted
As some of you probably know my stock m52 bottom end let go about 8 months ago and it's time to rebuild her. Before I was making around 500whp on a gt3582r. Now I'm looking to build the motor and make some serious power. The issue with this is from looking around is there are far less people making 700whp + with e85 on an e36 platform, so it's a bit more difficult to get information. So here are a couple questions to get this started.
-How far to bore? I've heard a bunch of conflicting answers. Alot say leaving not enough room between cylinders is a disaster waiting to happen. Others
say a solid tune coupled with e85 and there really shouldn't be a problem.
-Turbo selection. I'm kinda wanting to go the route of ballin on a budget so I was thinking a BW paired with a RSI topmount manifold. I had my eye on the S366sxe but I'm not sure.
This is a rough start to my path for big power so I hope that some of you veterans making big power can help me out.
u owe my mule an apology
Ever since the cutting gaskets came out 700+ whp on a 86+ mm bore has not seemed to be a big problem. It’s my opinion that anything bigger than 85mm is certain death above 900 or so.
An s366, s366sxe, or s369sxe will all make 700 with room to spare. For the money the sxe’s are a no brainer over the cast wheels.
86 325es, 2.8L m50, S476sxe, ProEFI 128 ecu, e85, solid rear axle, TH400 trans, 28x10.5w slicks, zip ties, popsicle sticks, tape
best time 9.06 @ 151.8 mph, best 60 foot 1.30
Boosted
Great info. Any real reason to choose 366 over 369. I'm assuming I'll have a bit more headroom with the 69.Originally Posted by someguy2800
Troll level: Master
SXE369 will put you way up there, low comp 2.8 with s50 cams got me to 860whp, I think I can see 900 real soon.
Boosted
Any reason you didn’t bore yours out even marginally bigger? I believe your motor is built iirc.
Cantry Member
Those SXE turbos sure are affordable for the power.
Keep in mind that it’s going to take more than a turbo to get that power to the ground...... reliably.
Last edited by chikinhed; 04-08-2018 at 03:09 PM.
u owe my mule an apology
Correct, the motor is the cheapest part of making 700 whp.
86 325es, 2.8L m50, S476sxe, ProEFI 128 ecu, e85, solid rear axle, TH400 trans, 28x10.5w slicks, zip ties, popsicle sticks, tape
best time 9.06 @ 151.8 mph, best 60 foot 1.30
u owe my mule an apology
If I wanted to make 750 I would get the 366, if I wanted to make 850 I would get the 369, if I wanted to make 900 I would get something else.
86 325es, 2.8L m50, S476sxe, ProEFI 128 ecu, e85, solid rear axle, TH400 trans, 28x10.5w slicks, zip ties, popsicle sticks, tape
best time 9.06 @ 151.8 mph, best 60 foot 1.30
Boosted
At what point do driveshafts and axles snap pretty predictably even from a roll?
Also what clutches are you guys using for these really high torque figures?
Troll level: Master
I like the RPM, when it made 869whp it was on a stock piston m52 with eagle rods.
And you will need a driveshaft, stock m3 axles work fine, but from a roll you will start to break diff ouput flanges above 800.
Boosted
Haha. What’s the go to for driveshafts these days?
Also how do you fix the output flanges breaking? Or is there a solution
Member
210mm diff takes care of axle output flanges.
Member
At the dragstrip on drag radials you can break 188mm diff stubs at anything over about 500 lbs rwtq.
Butters makes nice M3 axles. John at CES puts 850 rwhp through them to run in the 9s at 145+. He also runs a Butters built 210mm 4 clutch 3.15 diff.
Last edited by pbonsalb; 04-08-2018 at 09:38 PM.
Boosted
Funny how all this adds up underneath. Looks like....
~1000 driveshaft
~1300 axles
Don't even want to know how much a butters built 210 is :o haha
Cantry Member
You don’t need any of that stuff until they break. By then you will be so addicted to the power that the cost won’t matter.
Member
Have you seen the 87mm blocks fail past that? Wasn't Boris running 87mm with 1/2" studs with 4 figure power past 8k rpm repeatedly? All things you're not "supposed" to do...
u owe my mule an apology
Lots and lots of them. They crack the cylinder walls. Sometimes through the head bolt holes, sometimes between cylinders, sometimes down the side of the block. Most of the people making that kind of power have been through several motors. I've been told borris runs a 2.8 now after blowing up a bunch of them. I could be wrong on that, I don't have any contact with him. S54's have the same problem.
86 325es, 2.8L m50, S476sxe, ProEFI 128 ecu, e85, solid rear axle, TH400 trans, 28x10.5w slicks, zip ties, popsicle sticks, tape
best time 9.06 @ 151.8 mph, best 60 foot 1.30
Member
Cool, guess I'll keep mine to 900 :P
Boosted
You have a Dyno graph of that run? Also s52 crank or no?
Can’t for the life of me decide to go big bore or not. Seems like the bigger you go you are kinda playing with fire....
Last edited by bavdrftr318; 04-09-2018 at 06:31 PM.
u owe my mule an apology
At 700 I wouldn’t worry about it.
86 325es, 2.8L m50, S476sxe, ProEFI 128 ecu, e85, solid rear axle, TH400 trans, 28x10.5w slicks, zip ties, popsicle sticks, tape
best time 9.06 @ 151.8 mph, best 60 foot 1.30
Troll level: Master
Posted that graph in the big torque thread, no s52 crank it was an 84 bore and 84 crank.
Boosted
Graph I saw had speed on x axis. Did I just miss the one with power vs rpm?
Sent from my iPhone using Tapatalk
Troll level: Master
Sorry, the dyno had interference with the graph via rpm, you can do the math if you are curious, 2.93 rear 3rd gear, 7800rpm redline 275/50r15 tire
Its laggy but it works
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