Hi All - OK - short background: I have a BMW E36 with a 5.7 liter LS1 engine in it bult by Thomson Motorsports. It was installed back in 2017 (prior owner) and uses an ECU from a CTS-V tuned with HP tuners. The car is for road courses only and at a recent event, it looks like the #7 cylinder has gone bad. 40psi compression, 95% leak down; air coming out crankcase vent. The engine has a recently installed dry sump system from Aviaid. Valve train, so far, looks all good, and super clean. On track, coolant temps were in the 206 range; oil in the 230 range, and oil pressure ~55psi under load/revs.
I'm considering an LS3 crate engine; specifically the 6.2L 495HP part number 19435100 and running a haltech Rebel LS to control it. Goals are reliable power; 400HP to the wheels would be nice. Thoughts? Bad plan? Better plan?
Thank you!

-Joe

 

The crate engine sounds like a good choice for you, but I would stick with the same ECU and just get it tuned for the bigger displacement engine. IMHO, a Haltech ECU would be a waste of money and time for such a stock enginel; you would have to rewire the car and more. It will take only a few snap-in harnesses for your LS1 harness to run the LS3. A camshaft harness and a knock sensor harness come to mind. Since your ECU was from a CTS-V, it likely was for a 58x reluctor wheel (crankshaft) which is what LS3 have. If an older ECU/PCM, you can use a 58X to 24X converter box which is about $290.

 

Rebel LS is a good chouce, however if it was me I would be looking to also mate it to an 8Hpx0 box (even plan for it later if not at the same time), so then it would make more sense to go to a MAXXECU to run both.

 

Current engine has a 24x reluctor wheel - didn't know there were conversion boxes! Good to know. No plans to swap out the T56 for an 8HP. I know the 8HP is faster, but damnit - I'm shifting my own gears!

 

Yes, Lingenfelter makes the 58x to 24x conversion box. Plenty of members here have used it successfully.
As a road course racer myself, yes a manual trans is the way to go.

 

Will I need to upgrade the factory rockers, or is that something GM addressed with the crate engines? I've heard horror stories of needle bearings running through the engine.

 

just curios why you think manual is better than a 8Hpx0 used in manual mode?

 

Nothing wrong with a crate LS3

I recommend the base LS3 and put your own cam in. The higher HP LS3 crates all have a GM cam kit installed to boost the numbers. The rest is stock LS3

By CTSV ECM, do you mean E40 (24x) or E67 (58x)?
58x to 24x conversion boxes do exist, but are annoying because the engine has to crank over several revolutions before the triggers sync. On a track car, that's no big deal. Daily, it's irritating

If you're considering aftermarket control, look to holley terminator x/xmax. Cheaper than Halltech, very user friendly and pretty reliable

You're thinking of rocker trunion failures. All GM LS engines from basic 5.3 to mighty LS9 have the same style rocker bearing. Aftermarket is your only option to rule that particular failure out. Buy your favorite brand and spend a few hrs with a press installing them. Easy peasy

If you change oil pans, be sure to prime the engine before starting. A dry oil pump will never build oil pressure

 

My .02?
I think I would replace the LS1 ECM with a GM LS3 ECM that matches your new LS3 and call it a day. It means a new engine harness. But your old harness LS1 harness and ECM are very saleable.
I did a E36 vert LS1/T56 swap a number of years ago. Just a summer cruiser. Was a great swap.
With the 495 LS3 and T56 400 RWHP will be no problem.

 

Its mostly a matter of driver "engagement". Even in cases where the automatic might be faster, most serious road coarse drivers say they prefer a manual.
Personally I would not want abrupt gear changes in the middle of a corner. Whether I am shifting up or down in the middle of a corner, I make it gradual with the clutch.
I suspect the fast road coursing racing factory cars (Porsche, BMW, etc) with automatics have the transmission shifting tied into the stability control to anticipate traction issues in turns.
So call it personal preference, especially for people like me who started road course racing in the '80s in cars with no nannies.

 

"By CTSV ECM, do you mean E40 (24x) or E67 (58x)?"
I don't know - all I know is that the ECM is from a Cadillac cts-v and has a tune on it from HP tuners. The engine is from Thompson Motorsports and is a 5.7L LS1. The thing about the Rebel LS engine computers is it's actually a chunk *less* expensive than a new GM computer and about the same cost as the Holley. The drawback, of course, is dyno time, but the benefit (for me at least) is CAN connectivity to all the logging to match that up with lap times. That said I think any of the options (GM, Holley, Rebel) all support CAN now. The Rebel LS comes with a new harness, and has an integrated PDM for things like fans, fuel pump, etc.
I've been using AiM stuff for a while so I'd like to continue down that path for data logging/lap times.
Current engine compartment - and yes, that yellow stuff is pollen....
Very much appreciate the help / ideas.

 

appreciate your reply, and pretty much was the same until I drove aftermarket controlled 8hp70 behind a 2JZ. My daily also has an 8hp7x box funnily enough and I find it annoying at time with the shifting as you describe (2021 standard 3XMc as you are bmw owner), but for track and drift I see the benefit in not just shift change times.
‘But I still enjoy the old school manual clunkiness of the synchro and thought it was just me

 

First, I assume you have seen this current thread of an LS swapped BMW using the Haltech Rebel ECU:
https://ls1tech.com/forums/conversio...-3-tr6060.html
Contact him for likely better advice than any of us can give.

Next, it is important to know if your current engine is 24x or 58x. While LS1 is 24x from the factory, Thompson Motorsports may have built it as a 58x.
The color of the crank sensor (by the starter) will tell you: 24x are Black and 58x are Grey.

As far as I know, the GM 24x PCM are not CAN connected or aware. The 58x are, especially later ones.
A picture of the current ECU will tell us what it is.

 

Pretty new here - so no, I've not seen that thread. Thank you! What a build! I looked under the car briefly for the crank sensor near the starter, but could make it out. Here is the current engine computer:

 

Total guess on my part but the pic above is a 24 tooth LS1 ECM. It can control both the engine and auto trans.
My 98 Wrangler with a LS6/4L60E swap the ECM looks similar.
My 80 Camaro with a 2012 LS3/4L60E the ECM looks totally different from the pic above. With a 58 tooth engine you need to have a ECM for the engine and if running a auto a TCM controlling the auto trans.
Having said that I built a 73 Camaro with a 2010 LS3/TKO 600 combo. Only needed a ECM for engine, fuel pump, fan control and gauge inputs.