Replacing engine, need some input.

[odj]

Hello All -

I had been happily beating the crap out of my car on track for the past few years until a money shift ended my fun. I angrily parked the car and ignored it for a while, with my 986 filling in for track duty. I'm ready to get the 135 back on the road, and have some questions for the forum hive mind.

With a focus on reliably running laps over absolute power figures...

1. Is it worth going with a later N55, or should I just stick with the B30?
2. I'm planning on doing seals/gaskets, water pump, spark plugs, belt, tensioner, belt guard, and a VAC pan before the new engine goes in. Any other recommended engine work while it's out?
3. I've always run the engine completely stock + JB4. What are the recommended mods/tune for general track use? IC? MHD?
4. I've always run 200TW tires and would like to move to slicks, but have been afraid to do so due to folks' reports of oil starvation. Is an accusump really necessary to prevent it?

I know some of these are pretty big questions, but I'd like to hear people's opinions. If you have suggested links I'm happy to read, but I'm mired in a bit of analysis paralysis at the moment.

Edit:

The car is a 2013 135is, lightly modded:
JB4, charge pipe
Poly RSFB, M3 arms, Ohlins, BW rear camber arm & front upper control arm sphericals, E93 FSB
Stoptech Trophy fronts, stainless lines
Diffsonline LSD
Roll bar & seats

Thanks!

[odj]

Here's the old girl, disabled and ready to load on the trailer.

[Dieselboy]

The difference in reliability between the N54 and the N55 isn't enough to warrant an engine swap in my opinion, but it also depends on the cost to rebuild vs buying used.

I don't know your budget, or mileage, but I would certainly consider replacing turbos with the engine out of the car, it's not a fun job to do with the engine in. Consider engine mounts as well.

MHD flash tune for sure. If your goal is laps > power, then focus on cooling, for engine and brakes. Secondary oil cooler, larger intercooler, brake ducts, CSF radiator, etc..

Personally I wouldn't run on track without an accusump. The data on sump baffles hasn't convinced me to be enough to prevent starvation, especially with R compound tires or slicks. As your lateral loads increase with more grip, the oil starvation issues will worsen. Since this seems to be the primary reason N54's pop on track, it makes sense to do it right.

[odj]

Originally Posted by Dieselboy

The difference in reliability between the N54 and the N55 isn't enough to warrant an engine swap in my opinion, but it also depends on the cost to rebuild vs buying used.

I probably should have mentioned, but it's already an N55. And I have yet to tear it down, but I'm doubtful a rebuild is in the cards. It dumped a bunch of oil on the trailer on the way home, my assumption is that there's a hole in the block somewhere.

Originally Posted by Dieselboy

I don't know your budget, or mileage, but I would certainly consider replacing turbos with the engine out of the car, it's not a fun job to do with the engine in. Consider engine mounts as well.

Eh, I'm still trying to figure out my budget as well, but I'm figuring I'm in for 10k all said and done. The car has 54k on it. And I'll definitely look at upgrading the engine mounts while it's apart - I always felt that the stock units were too soft.

Originally Posted by Dieselboy

MHD flash tune for sure. If your goal is laps > power, then focus on cooling, for engine and brakes. Secondary oil cooler, larger intercooler, brake ducts, CSF radiator, etc..

The car has the PPK2 on it, so I do have some extra cooling already, but I'll look at the radiator options. Brakes have been alright without any additional ducting - I installed the F30 backing plates back when I was running stock brakes, and haven't had any heat related issues up front since I upgraded.

Originally Posted by Dieselboy

Personally I wouldn't run on track without an accusump. The data on sump baffles hasn't convinced me to be enough to prevent starvation, especially with R compound tires or slicks. As your lateral loads increase with more grip, the oil starvation issues will worsen. Since this seems to be the primary reason N54's pop on track, it makes sense to do it right.

Fair enough. I've read the spool street thread through a few times and that seems to be the consensus. I don't like the complexity that the accusump adds, but if it keeps the car on track for a while it's worth the work.

Thanks for the input.

[Dieselboy]

Originally Posted by odj

Eh, I'm still trying to figure out my budget as well, but I'm figuring I'm in for 10k all said and done. The car has 54k on it. And I'll definitely look at upgrading the engine mounts while it's apart - I always felt that the stock units were too soft.

I would recommend solid mounts, as the Poly mounts seem to melt quite often on the turbo side. I'm full solid (engine, trans, subframe, diff) and I have the dual plate clutch, so it's about as harsh/loud as you can get, and personally I don't think it's that bad. Depends if this is a daily or track focused car.

50k seems to be the time when these turbos tend to get a bit tired when they're pushed hard. At the very least it may be worth looking into a wastegate rebuild kit.

Originally Posted by odj

The car has the PPK2 on it, so I do have some extra cooling already, but I'll look at the radiator options. Brakes have been alright without any additional ducting - I installed the F30 backing plates back when I was running stock brakes, and haven't had any heat related issues up front since I upgraded.

You can do brake ducts pretty cheaply if you eventually run into problems. The ceramic pistons tend to deteriorate when pushed hard. This was my solution for < $100. https://www.1addicts.com/forums/show...&postcount=156

Originally Posted by odj

Fair enough. I've read the spool street thread through a few times and that seems to be the consensus. I don't like the complexity that the accusump adds, but if it keeps the car on track for a while it's worth the work.

Yes, the accusump solution is a pain, but so is tracking an N54/N55

[odj]

Originally Posted by Dieselboy

I would recommend solid mounts, as the Poly mounts seem to melt quite often on the turbo side. I'm full solid (engine, trans, subframe, diff) and I have the dual plate clutch, so it's about as harsh/loud as you can get, and personally I don't think it's that bad. Depends if this is a daily or track focused car.

Noise doesn't bother me. This is a track only car at this point. Solid it is

Originally Posted by Dieselboy

50k seems to be the time when these turbos tend to get a bit tired when they're pushed hard. At the very least it may be worth looking into a wastegate rebuild kit.

Fair. I'll take a look at it when I pull it out.

Originally Posted by Dieselboy

You can do brake ducts pretty cheaply if you eventually run into problems. The ceramic pistons tend to deteriorate when pushed hard. This was my solution for < $100. https://www.1addicts.com/forums/show...&postcount=156

I cooked the front and rear pistons on the stock brakes. I'm running Stoptechs up front, and will need to rebuild the second set of rear brakes soon.

Originally Posted by Dieselboy

Yes, the accusump solution is a pain, but so is tracking an N54/N55

[Dieselboy]

Ah, I see your mod list now. I have been looking at the ST Trophy's so I haven't done anything with my brakes yet. Hoping there's a Black Friday sale or something this year on those. $5k for two calipers is hard to justify, but really is the best solution.

[odj]

Originally Posted by Dieselboy

Ah, I see your mod list now. I have been looking at the ST Trophy's so I haven't done anything with my brakes yet. Hoping there's a Black Friday sale or something this year on those. $5k for two calipers is hard to justify, but really is the best solution.

I snagged them for a phenomenal deal ($2500) when Turner was blowing them out. They've been great.

[carguy138]

FYI I still popped my N55 with a 3 quart accusump. Made it through 2x 15 minute sessions before a rod bearing let go. Ended up going with a new longblock from Miami Engines (and added VAC coated rod bearings, ARP hardware and forged M2 crankshaft). For some context I'm the second owner, 72k miles and have had it for 8 years. Oil changes every 4-5k, always warmed up/cooled down and maintained the utter hell out of it.

Accusump did help under braking but it only provides 5-6 seconds of oil pressure. The track I was running on had one of the NASCAR ovals open and that's what cooked the motor. 10-11 seconds in 4th gear at 80-90mph.

Shame because the chassis felt GREAT cornering at this speed.

IMHO I'd just go easy with any N55.

[odj]

Originally Posted by carguy138

FYI I still popped my N55 with a 3 quart accusump. Made it through 2x 15 minute sessions before a rod bearing let go. Ended up going with a new longblock from Miami Engines (and added VAC coated rod bearings, ARP hardware and forged M2 crankshaft). For some context I'm the second owner, 72k miles and have had it for 8 years. Oil changes every 4-5k, always warmed up/cooled down and maintained the utter hell out of it.

Accusump did help under braking but it only provides 5-6 seconds of oil pressure. The track I was running on had one of the NASCAR ovals open and that's what cooked the motor. 10-11 seconds in 4th gear at 80-90mph.

Shame because the chassis felt GREAT cornering at this speed.

IMHO I'd just go easy with any N55.

Thanks. This is some of the news that I keep reading that makes me just want to put the car back together and sell it, and find something else to use as a track car.

[amg6975]

Only way to solve N55 issues on track if you ask me:

[Gary@simod.net]

Replace the rod bearings with ACL race they have slightly more tolerance than OEM bearings and the bearing material is substantially stronger unlike the OEM bearings that are like butter... Run 1qt over and baffle the oil pan.

I believe you can also buy the OEM M240ir oil pan/pump set up which is what they ran on the N55 M235IR