Your churbo setup, if you could do it again what would you do differently?

[cleanasse30]

Hey r3vers,

I am in the beginning stages of my turbo build on my 325i. I've been researching general turbo system design and e30 specific turbo info for the past 4 or 5 months and have finally begun buying some parts to make this a reality. So my question for those of you that have already built a turbo system, what would you do differently if you could do it all over again? What do you love about your churbo setup? What are some key things you learned along the way?

Just looking to try and avoid making silly mistakes since this is my first N/A to churbo conversion. If we get some good conversations going, maybe this can help others looking to turbo as well.

[TheTacoMan]

Avoid 90% of ebay parts, buy quality first and you wont have to replace it down the road, also really consider what size turbo you want. Suite it to how you want your car to drive. I assume you are talking about a m20b25?

[mrcheezle19]

Definitely buy quality parts. I'm tired of the "trying to build a turbo for $999 or less!" crap. You don't have to go spend 20k, but do get solid parts.

[codrum]

I would not have bought cheap 42lb injectors - one of them stuck open and nearly hydrolocked my engine. I also probably would have gone with a different turbo than the H1C I picked up. It's too big for around town boosting, even with the BEP 12cm housing. Make a plan for the build, outline the total cost for good quality parts for every nut and bolt you can think of, then add $500 on top of that for shit happens.

[cleanasse30]

Avoid 90% of ebay parts, buy quality first and you wont have to replace it down the road, also really consider what size turbo you want. Suite it to how you want your car to drive. I assume you are talking about a m20b25?

Not going to use ebay parts other than the intercooler which i plan to get from CX racing. I am planning on getting a Borg Warner S256 RS from AGP turbo with the AGP .63 A/R Vband turbine housing so I'm not cheapin out, I want this done the right way.

I bought a custom tubular t3 manifold from another member on the forums which is the first part I have acquired for das churboing lol. As for engine, I plan to boost my high mileage m20 until it blows up or needs replacing from wear, but I am also currently working on buying a 2.7i stroker (eta bottom end, 885 head) from another member to swap in once I get the basics of tuning down. I will be using a whodwho MegaSquirt setup with wasted spark and electronic boost control to control the engine.

Definitely buy quality parts. I'm tired of the "trying to build a turbo for $999 or less!" crap. You don't have to go spend 20k, but do get solid parts.

This build will be done using quality parts. Plan to use Turbosmart vee-port BOV and Turbosmart Comp Gate 40 wastegate. Custom tubular manifold has been purchased off another r3ver and plan to buy a new turbo.

I would not have bought cheap 42lb injectors - one of them stuck open and nearly hydrolocked my engine. I also probably would have gone with a different turbo than the H1C I picked up. It's too big for around town boosting, even with the BEP 12cm housing. Make a plan for the build, outline the total cost for good quality parts for every nut and bolt you can think of, then add $500 on top of that for shit happens.

Yeah I've started a spreadsheet to figure out relative cost of parts as I research them and decide on what parts to buy. I understand its going to cost more than I anticipate now, this project is more of a learning experience for me than a "lets build a fast car for as cheap as possible" type thing. My e30 is also not my DD so im trying to build it for mid-range to top end power to occasionally use at the track as well as weekend spirited driving.

[redsubdivisions]

Generic answer: don't cheap out. Get quality stuff. If I could do it all over again, I would have bought a tried and true setup instead of hacking shit up.

[BMWManiac]

Yup, and I would have gone with either an authentic gt28r or gt30r turbo instead of the ebay gt35 turbo.....I want a faster spool on my m20 with just arp headstuds and oring block

[AbsorbantNut]

Get megasquirt!! I have a reliable setup on Motronic, but it took a while to make it reliable. Megasquirt would've initially cost more, but it is much easier to do and has cooler features than stock management.

[KrautnotRice]

There is some good advice in this thread. It seems like the OP asked the right question.
Bump for other veteran turbo-ers to share their experiences.

[ak-]

Quality parts.
Saving up for extensive work that you might regret not doing beforehand.
MS from the start.
Fail safe features, maybe knock sensors.

[cleanasse30]

Quality parts.
Saving up for extensive work that you might regret not doing beforehand.
MS from the start.
Fail safe features, maybe knock sensors.

Has anyone successfully put a knock sensor on the M20 that you know of?

[nightbear]

Yep same story here, ebay parts, all of them are a waste of money, except for an IC.
Also a good idea is to start with the clutch - get one that will hold.
A well configured standalone is a must too.

Oiling should be sorted out well, have had million problems with that, killed a couple of turbos. Oil drain should be as big as possible, at least 20mm, so opt for 12an+.

Oh and if you are not ready to spend 10k+ on your car, that will never return, just don't do it.

[BMWManiac]

And apparently, the oil line/fitting on my turbo is 1/2" and not 5/8" so now I have to redo my oil drain from -8 AN to -10 AN instead of easily being able to switch turbos....so confirm BEFORE install!