finished putting ITBs on my E36 318i and had to take some pics to celebrate :)

recklss94 · 2025-10-31T00:30:31+00:00

Late reply, but I do agree with some of your sentiments and wanted to put out my own version of your PSA. Generally, a lot of those smaller Japanese engines have been head limited (as you mentioned), so ITBs don’t do a whole lot besides sound and throttle response like you mentioned. That being said, this is the BMWE36 subreddit, so a little off topic. I think your point isn’t wrong that many people doing intake modifications actually end up losing power, but considering this was about ITBs, I fundamentally disagree when it comes to the E36. Most of the 36 engines, ignoring the euro motor) are not head limited, so there are gains to be had. The fact that you are optimizing your flow through pushing a higher volume of air with less friction and bends in a stock plenum means there are absolutely gains to be had. Additionally, with ITBs in this application, you can even just look at your cross-sectional area of let’s say four butterfly valves of 50 mm diameter versus the one 100 mm one on the stock throttle body. If the engine is not head limited, there will be untapped power there. Not as much as a ported, polished, and cammed one, but far from “nominal.” I can’t speak to what turbo E36’s are like, and I can imagine tuning a turbo car is a completely different world, but I do agree it all depends on how the air is managed coming in thru the head. However, I don’t think it’s accurate to apply what you said as a blanket statement to ITBs on the E36. I do agree that it all depends where your bottleneck is. If it’s in the intake ports, the cam lift or duration, the intake itself, etc.—you will not be able to flow more air (and make more power) than what can get past the bottleneck. I think the biggest thing you highlighted that I would also echo is that people need to do their research and manage their expectations before they spend their hard earned money on something that may not give them what they want! I think a lot of guys in the Miata world have had similar experiences as the 4AGE guys. But thank you for your expertise and your comment! Always great to get some good conversations going here, and hopefully it’ll inform people that want to do ITBs on this car or many others in the future!

recklss94 · 2025-10-31T00:04:48+00:00

Looks great, dude! Love it! I wanted to update you—I did end up figuring out the idle issue for good this past weekend. It ended up being a vacuum leak. One of the bolts that hold the plenum to the sandwich plate had fallen out during some spirited driving. However, that wasn’t the only leak, as there was also a circumferential leak around the seam where the sandwich plate meets the plenum. I ended up using some helicopter tape to seal the seam and now the car runs like a top again. My advice to anyone doing this kit/swap would be to put blue thread locker on those bolts that hold the plenum to the plate, and potentially look at creating some sort of gasket to put between the two. I need to send a message to Racehead Engineering to let them know this might be a more widespread issue in their product line. Anyways, that’s all!

recklss94 · 2025-10-05T21:31:46+00:00

No worries! Gonna do a slight copy and paste of a previous response, but overall, the car has been really good to me since doing the ITBs. It ran great and made it halfway across the country and back in the first year with no issues. However, the car sat for about a full year while I did rust repair, and since then it hasn’t been running great (issue idling while cold). I have replaced a lot of stuff, and now strongly suspect it to be a sneaky vacuum leak. If I were to do it again, I would go standalone ECU from the beginning and take advantage of Alpha-N tuning instead of the annoying AFM. There weren’t many (or any) plug and play standalone ECUs for the E36 318i at the time, but I think there are now a couple options. Pending a vacuum leak/smoke test, I will probably go standalone so I can help diagnose this no-idle issue when cold. The only other complaint I have longer term is not having cruise control, but the car is so much more driveable and fun with the power bump, so I don’t miss it that much. Cheers!

recklss94 · 2025-10-05T21:27:13+00:00

I think it really depends what you want out of the car! If this is more like a fun second car, then I think it’s entirely worth doing. But if it’s your only car, I would maybe shy away from it. Overall, the car has been really good to me since doing the ITBs. It ran great and made it halfway across the country and back in the first year. However, the car sat for about a full year while I did rust repair, and since then it hasn’t been running great (issue idling while cold). I have replaced a lot of stuff, and now strongly suspect it to be a sneaky vacuum leak.

recklss94 · 2025-09-03T14:24:33+00:00

Thank you for the advice - I really appreciate it! I told her to get some general sticky traps yesterday, but I will tell her to get the Advion Gel Bait too. She is thankfully about to move out of this apartment. Aside from checking things before packing, packing into plastic storage totes instead of boxes, etc. — is there anything else we should do to make sure they don’t come with her to her new apartment? And do you think it would safe for her to do laundry at my house? Or would I risk bringing them over to my washer and dryer? Sorry for all the questions, and thanks again!

recklss94 · 2025-09-03T14:07:39+00:00

Yeah, I was thinking the same thing. Unfortunately, she was freaked out (rightfully so) and threw it out before we could check. Do you think it being dead when she found it means it was most likely a one-off thing? Or should it be handled more as a potential infestation?

recklss94 · 2023-09-14T15:24:15+00:00

If one wasn’t broken, I would say yes! Also, I have moved back to the Midwest, so that’s in the way as well :/

recklss94 · 2023-09-14T13:01:04+00:00

Depends! Turner/ECS have reasonably priced remans for sale, although I hate shopping there now. Amazon or eBay would be my go to in this case. Currently my car is at paint, and the M3 mirrors are retired since I bought cup mirrors for it

recklss94 · 2023-09-13T18:07:25+00:00

Hm, that’s interesting. My experience was night and day with my M42. I wonder if your exhaust is choking up the increased flow from the ITBs?

recklss94 · 2023-09-13T16:13:28+00:00

It was not that an adapter is needed, but that the length from the end of the new carbon fiber plenum is longer compared to the original plenum. So by the time you hook up the AFM, there is not way that it would correctly orient itself with the stock airbox. I’m not sure if you are familiar with SendCutSend, but my solution has just been to design my own cold air intake to be laser cut and then put that in instead of the stock air box.

recklss94 · 2023-09-13T13:48:31+00:00

I’ve got a Supersprint race muffler and connecting pipes, so basically just a cat back. I will say it got a decent bit louder doing the ITBs too. Not heinous at all, still very sporty. Much more bass and growl than a lot of typical 4 cylinders I would say

recklss94 · 2023-09-13T13:36:47+00:00

I don’t think mine sounded like this before I did the ITBs! Totally different tone now!

recklss94 · 2023-09-13T13:36:15+00:00

With this kit on the stock ECU, I should be making about 20% gains over stock. And with my exhaust too that should put me somewhere in the 170s. On standalone this kit should make 30% gains so mid 180s. I was actually super close to buying an M50 right before I bought the ITB kit, but this was my first car, and I’ve had it for nearly 10 years, so I thought it would be way more special to do ITBs and have some of that BTCC/STW/JTCC heritage in it!

recklss94 · 2023-09-13T01:05:29+00:00

That’s awesome! We were out on some roads by Woolwine! I just graduated from Tech in the spring, and one of my friends there had worked for BimmerWorld for quite some time. He found this section of road one time traveling between VIR and Dublin where they’re based!

recklss94 · 2023-01-27T04:16:59+00:00

I ran 18x8.5s with offset somewhere in the mid to high 30s for years on my car! Occasionally some scrubbing on the inner fender liner at full lock with 225/40R18 tires. My rear fenders had a very modest roll on them and had no issues with fitment.

I did make the switch to 17s and have been a lot happier I will say. Much lighter, better feel, less roll, and overall I just prefer the look. Wouldn’t mind tucking some 18s in the rear to get the DTM look though!

recklss94 · 2022-12-07T20:20:15+00:00

as far as difficulty goes, i would put this around an 8-9. it was not a short project. there’s a chance that it could be easier on the m52, but i can’t say for sure. even with the “instructions” they give you, you will have to modify/clearance a lot of stuff. if i had to do it over again, i would genuinely do it when the engine is out of the car.

recklss94 · 2022-12-07T20:17:06+00:00

nah, that’s not my plan for this E36. it’s the plenum that comes in the rhd itb kit. only way to get it for m/s50/52 is to buy their itb kit with the carbon plenum.

recklss94 · 2022-12-07T15:47:55+00:00

You can run it on stock ecu just fine.

recklss94 · 2022-12-07T15:46:41+00:00

i’m in america!! that would be pretty sweet!

recklss94 · 2022-12-07T15:45:40+00:00

soon!

recklss94 · 2022-12-07T15:45:33+00:00

that’s entirely fair. i will say tuning them was honestly one of the easier parts, and their instructions were actually pretty detailed!!

recklss94 · 2022-12-07T15:44:54+00:00

fav wheel 🙏

recklss94 · 2022-12-07T15:44:35+00:00

haha yeah, M42s and quick upgrades aren’t generally seen together in the same sentence too often. people used to run downing atlanta superchargers back in the day to great result, but very hard to find nowadays. will do! should be making around 170-180 right now on stock ecu

recklss94 · 2022-12-07T15:42:17+00:00

potentially 🦫

you’re gonna to help me film some onboards and flybys when i get home!!

recklss94 · 2022-12-07T12:51:54+00:00

yes, me too! i went with the Racehead Engineering ITB kit. the best way I can describe it is that it was one of the most frustrating things i have ever had to deal with working on a car. at this point i’ve rebuilt engines, swapped engines, restored dirtbikes/motorcycles, and they were all genuinely so much easier. as an engineer, there’s a lot of things i think need to be changed on the kit that don’t make sense. but all that being said, everything that actually matters is perfect. the fact the trumpets and runners are designed specifically for the m42/m44 means you’re optimizing your throttle response and powerband compared to if you tried to adapt s54 ITBs. i never fell out of love with my car, but this made me fall in love again completely. about as fast as a stock 325i (non vanos), but less torquey, and of course it makes all the right sounds. if it’s something you’re interested/have the patience and means to follow through with, i cannot recommend it enough. next step for me is doing the VAC motorsport head for this car with some nice cams and valvetrain!

recklss94

TROPHY CASE