E24 Turbo Build

[TurboShark]

Hey everybody, I'm Paul, a 21 year old college kid that has been building rock crawlers for the past 3 years. I sold my pride and joy after building it for three years looking for something new to build. I happened to be friends with a buddy who has an amazingly clean E28. I always loved his car and the lines on the older BMW's. I wanted something that wasn't seen on the road often. I decided on an E24, and started scouring craigslist.

I picked up an 1985 635CSi with 112k on the clock. Odometer still worked, dash has one small crack in it. Most of the 24's are autos, and I wouldn't settle for that, and I ended up finding a 5 speed. Very clean interior. Outside is ok. Paint is in bad condition, especially on the top of the car. It has been resprayed, and the one thing to cheap out on is clear coat, AMIRITE?

Anyway, I fell in love with the car. Handles great even with stock suspension. It's pretty fast for me, but the fastest automobile I have owned was my 04 quad cab 5.7 hemi Dodge Ram, so that doesn't say much. I always have wanted to go fast, so that's why I picked this thing up. After only a week of driving it, I decided to tear it down for a turbo.

I started in August 2010 building a 1987 Suzuki Samurai. I ended up building it longer than I ever actually got to wheel it, but I got a lot of enjoyment out of learning fabrication and building it. I taught myself how to weld and fabricate. I linked the front and rear suspension, built an entire cage, engine swapped it, stretched it 6" in the front, 12" in the rear, and a lot more. I learned a lot. I picked up another project about 4 months ago, a 1987 4Runner that I solid axle swapped, put on 35s, and other small things. Here's a few pics of the rigs for those that care:













On to the E24..

Towing it home



Even has the dealership option radar detector. Doesn't work, but looks awesome!







Owner replaced the "comfort" seats with the E24 sport seats. I'm going to end up dying them to match the rest of the interior.



Build Plans:

H1C turbo (Same as HX35 but larger exhaust housing)
30lb Bosch injectors
TCD timing chip
BEGi FMU
eBay 38mm wastegate
Tial 50mm BOV
Flipped manifolds
eBay intercooler

Ground Control suspension (they are only about 20 minutes from me)
BBS Style 5's

So far this is where I am..

Welded up the internal wastegate on the H1C



And started on a VERY crude beginning to a manifold





Like I said in the title, this is my first car (besides my '70 VW Baja Bug) and my first turbo build. I barely knew anything about turbo systems before I purchased the BMW so I have been doing a lot of research on forums about stuff, but I definitely am still a novice on this stuff so if there is anything I need to know, or any constructive criticism please let me know.

[Nebraska_e28]

Welcome aboard!

\subscribed

[TurboShark]

So far what the manifold looks like. Pretty much done just have to fully weld everything.







Also got the injectors installed, and started sorting out the piping for the intercooler.

For people that have turbo'd a b34.. Where have you tapped into for oil feed? I have heard of oil pressure sending port on the head and also the oil filter housing. I was going to go with the oil pressure sending port because its closer and easier, plus I already bought the fitting. Will I need to run a restrictor for the feed or will it be ok? Also, has anybody ran the AFM on a turbo'd engine? I'm looking for between 12-15 psi and if I have to I'll go with the Miller MAF/chip but I'm trying to do this on the cheap. Any info is appreciated!

[T_C_D]

Cool project. Tap oil filter housing for oil pressure. AFM needs to be draw through to work properly which like a near impossibility with your setup. Some have used it as a blow through but I don't have any first hand knowledge.

Todd

[TurboShark]

If I tap into the oil filter housing will I need a restrictor?

[turbodan]

The main difference between blow through and draw through is how many feet of piping you're going to have containing metered air. Draw through also requires a recirculated dump blow off valve.

I had great results with my blow through system. The AFM functions as normal and the RRPFR accounts for the air density once you start making boost.

[TurboShark]

Does the stock b34 have a blow through or a draw through? I'm guessing blow through after looking at the AFM briefly. I just need to know if I'm going to need to get the Miller MAF/war chip to replace the AFM. Also do you have to have the war chip to run their MAF? I already purchased a timing chip from TCD. And what does RRPFR mean

[Jelmer538i]

The turbo looks just like the one on my brothers first gen Cummins!

[TurboShark]

Yup, same turbo. The H1C came on the first gens. I was planning on going with the HX35 which came on the second gens (still 12v) but the HX35's had a smaller turbine housing. I have the HX35 on my 12v tow rig, and it boosts really high (maxes at about 30psi). I'll have two straight six holset turbo'd vehicles when I'm done

[turbodan]

Does the stock b34 have a blow through or a draw through? I'm guessing blow through after looking at the AFM briefly. I just need to know if I'm going to need to get the Miller MAF/war chip to replace the AFM. Also do you have to have the war chip to run their MAF? I already purchased a timing chip from TCD. And what does RRPFR mean

You can run the AFM in either configuration. I had good results with the blow through. I wouldn't worry about getting rid of the AFM. Motronic isn't any better with a MAF. Megasquirt is an upgrade but the learning curve is like a brick wall.

The RRFPR is a rising rate fuel pressure regulator. You do your fuel tuning with that. It boosts fuel pressure as manifold pressure increases. I recommend the BEGi 2025, which uses a variable bleed design allowing fine tuning of the rate of rise to dial in precisely the amount of fuel you need. With the RRFPR handling fuel enrichment you just need to consider ignition timing, which the TCD chip takes care of up to a certain boost pressure. You can make more power than you need with Motronic and a RRFPR.

[TurboShark]

Already have the BEGi 2025 and the TCD chip. Only downside to the AFM is its so damn big. Having to put that, the vent to the valve cover and the (what I'm guessing) the idle air control valve in line of all the intercooler piping will be a task but shouldn't be too bad.

[TurboShark]

Already have the BEGi 2025 and the TCD chip. Only downside to the AFM is its so damn big. Having to put that, the vent to the valve cover and the (what I'm guessing) the idle air control valve in line of all the intercooler piping will be a task but shouldn't be too bad.

[turbodan]

You're going to have to vent the crankcase to atmosphere. The stock crankcase breather works great until you introduce boost, at which point you'll be pressurizing the crankcase. If you've got a tight motor you shouldn't have much oil if any coming out of that breather, but if you do just run a catch can.

[TurboShark]

Ok, easy enough. I'll run it to the atmosphere for now and see if theres enough blowby to run a catch can. Should be ok though.

Does anybody have pictures of their engine bay running the stock AFM? Going to have a little bit of a puzzle on my hands trying to snake the charge piping between the wastegate and everything else still including the IACV and the AFM. Any pictures for reference would be nice.

[Jelmer538i]

Yup, same turbo. The H1C came on the first gens. I was planning on going with the HX35 which came on the second gens (still 12v) but the HX35's had a smaller turbine housing. I have the HX35 on my 12v tow rig, and it boosts really high (maxes at about 30psi). I'll have two straight six holset turbo'd vehicles when I'm done

You can get different exhaust housings for the H1C if you want to change it. I had a first gen and a second gen 12v and I both loved them! What a torque!

[TurboShark]

I absolutely love my 12v. I tow my crawlers all the time like its nothing. Give or take about 5000-6000 pounds including the trailer and I can let off the brake at a stop light and it still starts to roll forward wanting to go. Love them! Plus they last forever!

[Brad D.]

Very cool build. The Samurai is awesome too!

[TurboShark]

Small update. Got the BEGi installed and mounted. Valve cover back on, wastegate bolted up. Intercooler is halfway mounted. I also started on the not fun process of taking the pan off. I got the oil filter housing off today as well. I'm hoping to be done with everything and can take it to the exhaust shop within the next week or so. I'll keep it updated.

[TurboShark]

Update time, got a lot done in the past week.

First time working on a BMW, and an M30 for that matter. Holy shit it was such a pain in the ass to get the pan off. But I did and got my 12AN return bung tig'd on by a buddy. Also got the oil filter housing tapped for the feed line.





Opened up the DME and put in the timing chip from TCD



Biggest thing was I got the entire exhaust done by a guy my buddy knows. He hooked it up and did a great job. Entire downpipe is all mandrel bent. 2.5" all the way back, no cats, and a single Magnaflow glasspack type muffler. It's going to be loouuuddd







Also got the hardest part of the intercooler plumbing done. Had to figure out the puzzle of mounting the AFM, and not getting in the way of where the wastegate is going. Was tricky but it's done.



I made the mounting plate for the intercooler, so just have to weld supports to the bumper for it. Getting my new Tial wastegate tomorrow (fleabay wastegate ended up not being what I needed). Oil lines are done, getting the v band flange tig'd on to one of the intercooler pipes tomorrow for the blow off valve. I should be driving it by the weekend if everything goes right.

[TurboShark]

This is where the forums come in handy! I need some help tuning it guys. Everything is done with it, but I've been having problems even getting it to run. I'm sure I have overlooked something or I didn't do something correct, I'm hoping one of you can point it out for me.

I tightened up the AFM spring, installed an Innovate wideband and started it up. It's weird, sometimes it runs when I start it up and sometimes it doesn't. If it does though, it is EXTREMELY lean. like barely sputtering still showing 22.4 on the wideband. I flipped the AFM over and popped the black cover off so I could adjust the spring while the engine is running. If I use my finger and open up the AFM door a little bit, it richens up a lot and runs great at around 14 AFR. But if I let it go, and the door closes it goes back to being super lean.



That little half circle on the left that sends the signal to the computer that the door is open I'm guessing tells it to dump more fuel, since there is more air. So it makes sense when I open the door up with my finger that it runs a lot better because it is sending more fuel through the injectors.

I went to every silicone coupler on the charge pipes and sprayed brake cleaner around them to rule out a vacuum leak, as well as all around the valve cover/vacuum lines. Everything is good. Also when it does idle (very lean) it smokes like a son of a bitch. Idk if that says anything.

I backed the center screw off the RRFPR a lot to make sure that wasn't doing anything to throw things off, and it wasn't. Anybody have any ideas? Frustrated to say the least, but I've been in these situations before . I can fabricate all day and have a great time but the minute I have to get an engine to run correctly I'm done, don't have the patience for this stuff!

[mooseheadm5]

Check your fuel pressure.

See what happens when you run it on a stock computer (just don't boost it while testing.)

[TurboShark]

I will get on that. I could suspect fuel pump, but when the AFM is open a little bit it runs like a champ. But then again when I go to rev it, it falls on its face and nearly (sometimes) dies.

What do you mean run it on stock computer? It is stock, only the timing chip is in there.

[mooseheadm5]

Swap the chip back to stock.

[TurboShark]

I'll try that to rule it out as a possibility.

[//grecko//]

your afm Is not supposed to be before the turbo?

[TurboShark]

Everything I've read, the AFM goes right before the intake. Can somebody else chime in on this? Need to make a new manifold if that's so..

[rwpg]

I think your idle valve needs to between the afm and throttle body. My guess is it`s passing air around the afm so theres no fuel being added to the idle flow.

[TurboShark]

Ahh! Finally something that makes sense! I'll go switch it around, thanks for the input!

[TurboShark]

Ahh! Finally something that makes sense! I'll go switch it around, thanks for the input!

[rwpg]

So here’s some theory that I pieced together after doing quite a bit of reading up on Turbo systems to figure out what made sense in the placement of the intake system components and why it made sense. Then I looked for photos of different factory turbo systems and found that almost all simple factory turbo systems follow the same basic layout:

Filter => AFM/MAF => Turbo => Intercooler => Blow-off => Idle-Valve => Throttle-Body

The Blow-Off valve can be almost anywhere in the charge pipes but it should dump back into the intake system between the AFM/MAF and the Turbo intake. This is done to recirculate the already computer-measured intake air back into the system without the computer re-calculating the same air flow twice and over adding fuel at the injectors. It’s slamming the TB shut that drives up the charge pressure and pops the blow-off open. The purpose is to dump the over-pressure air before it overloads the turbo (bearings I believe) while the turbo has not yet seen reduced exhaust pressure from closing the TB

The Idle-Valve is to take the computer-measured intake air and pass it into the manifold bypassing the throttle body which is basically closed at idle time

Crankcase vent (from the valve cover) can also be passed to the intake between AFM/MAF and the Turbo. This is to stop the charge air getting into the crankcase backwards through the valve cover vent pipe.

The gas fume vent pipe from the carbon filter should also be passed into the intake between AFM/MAF and the Turbo. I’m surmising here but if the carbon filter vent is connected into the charge pipe (as you have) then the charge air can go back through the vent system an into the gas tank. That could be interesting

The above is how I set up my system which I have not yet finished so that’s why I stated “theory”. I did it this way as a result of the reading and picture/diagram hunting and wanting to stay a little bit eco-friendly. I also noticed many non-factory setups that do the following:
• Dump the blow-off air into the atmosphere. This may result in little explosions out the tail-pipe as that dumped volume of air is not passed into the engine but the computer pumps in the gas at the injectors expecting that dumped air (AFM/MAF input tells it to do so) which as a result over richens the mixture
• The crankcase vent is often vented to the atmosphere or passed into the exhaust manifold after the turbo

I tried to get the above validated on this forum but nobody has answered

This isn’t a very good photo but it shows the e23 745 turbo setup and it follows the same basic pattern of intake assembly http://us1.webpublications.com.au/stati ... 50_4lo.jpg
AFM is before the Turbo air intake.

Hope this helps