Criticize My Turbo Build Plan

[NathanR]

Hi all,

I've been working through sorting out getting my 1987 325e with an M20B25 prepped for a turbo. The car is reaching a point where it's pretty solid, so I'm starting to try to plan out how to go about getting some more power. Engine-wise, the M20B25 in the car had a fresh rebuild within the last 5K miles, and has a brand new head. I have attached my proposed build sheet, and have roughly selected the vast majority of components, but I have a number of questions to help point me in the right direction, and am generally looking for anything I may have missed or any criticisms to my plan thus far.

My plan for the car is a target reliable 350whp (please let me know if I'm being realistic here). I'm not wanted to go super budget-build, but looking to do a mid-tier, and am open to alternatives that can help me save some cash here and there. My target for the build is under $7K, which I'm already exceeding without including a diff or any fabrication (I'm capable of doing all of the "bolt-on" work, but don't have the equipment nor the skills to do any fabrication. With that said, I'm aware that I'm likely going to need to increase the budget by a grand or two if I can't find some ways to cheapen it up without making it less reliable.

Here's my questions (numbered to make the direct answers easier):

1. What am I missing? Besides ignition, (see question 5)
2. I have a number of turbo options listed here, but it's difficult for me to parse through each and make a decision, open to suggestions here, though I want to note that I would like something with a T51R Mod if possible (it's the inner child in me that requires this)
3. Looking for information to help me decide on a wastegate from my included options or other suggestions.
4. Looking for information to help me decide on a BOV from my included options or other suggestions.
5. I currently have a 4.10 LSD that came with the car from factory. Are there options to regear, or is it better/cheaper to just sell the 4.10 and buy something else?
6. What do I need to run a wasted spark setup?
7. Do I really need to O-Ring the block? I don't mind doing it but buying the $400 Isky tool to use once bums me out a bit.
8. What intercooler is suggested to use that allows me to keep A/C? I live in Central Texas, so A/C is a must.
9. I have High Flow Cat in here just because the car is currently cat-less and my Fiancée hates the smell, but I don't want to add back pressure issues so if it's recommend to keep it as is, that's fine with me.
10. At 350whp, am I going to run out of brakes? Given the car's existing lack of safety equipment, I'm happy to add a BBK, but ultimately it will push out the turbo build to fund it, which is fine, but would like to know now rather than later.

I'm sure I'm missing a couple of questions here, so apologies in advance, but thank you for your help!

Also if anyone wants to follow my build, I'm @shts_fkd_garage on Instagram!

[AWDBOB]

Buy a full kit from ClassicDaily. His kit retains A/C, uses Pulsar G30 copy you want to use, and you can get it all done in your budget, including ECU. It's not on his site, so you have to email.

Suggestions:

-Don't waste your $$ on a cam, stock cam is fine for a turbo car
-Use an eBay FX clutch to save $$, they're great and I don't see them as a compromise.
-Sell your s4.10 and buy a different limited slip and you'll have an almost even swap vs all the new diff setup costs
-Buy the whole LS coil kit and ECU from ClassicDaily.
-Head gasket is a fuse. At 350whp you should keep a stock gasket, if you're popping HGs something is failing so if you oring the block you have a higher chance of melting a piston instead of blowing a HG
-I wouldn't worry about a hi flow cat hurting back pressure, non-issue
-Stock brakes are fine with some nice pads/rotor/fluid
-Their FMIC & piping kit is meant to work with A/C

My buddy just did all of the above and his car has been incredible.

His dyno results are here:

https://www.r3vlimited.com/board/forum/e30-technical-forums/engine-drivetrain/m20/378740-forcedfirebird-s-m20-dyno-thread?p=10123560#post10123560

[e30davie]

What ecu is the classic daily based on? mega squirt?

[jakeb]

What ecu is the classic daily based on? mega squirt?

No it runs FOME. Much better than megasquirt by todays standards.
Deets here, https://www.classicdaily.net/collect...g-and-play-ecu

[e30davie]

Interesting, the onboard wideband controller and knock sensor are massive upgrades

[NathanR]

Buy a full kit from ClassicDaily. His kit retains A/C, uses Pulsar G30 copy you want to use, and you can get it all done in your budget, including ECU. It's not on his site, so you have to email.

Suggestions:

-Don't waste your $$ on a cam, stock cam is fine for a turbo car
-Use an eBay FX clutch to save $$, they're great and I don't see them as a compromise.
-Sell your s4.10 and buy a different limited slip and you'll have an almost even swap vs all the new diff setup costs
-Buy the whole LS coil kit and ECU from ClassicDaily.
-Head gasket is a fuse. At 350whp you should keep a stock gasket, if you're popping HGs something is failing so if you oring the block you have a higher chance of melting a piston instead of blowing a HG
-I wouldn't worry about a hi flow cat hurting back pressure, non-issue
-Stock brakes are fine with some nice pads/rotor/fluid
-Their FMIC & piping kit is meant to work with A/C

My buddy just did all of the above and his car has been incredible.

His dyno results are here:

https://www.r3vlimited.com/board/for...0#post10123560

This is all super helpful!

I did reach out and Jake gave me some great info, thanks Jake!

Some follow up questions I have:

1. I've removed the cam from my list, what about the rocker arms and valve springs? Will I be okay with just the new stock head?
2. Do you have a link to the knockoff FX400? Or the brand name?
3. What's the benefit of the LS Coil Kit vs. the Wasted Spark setup?

[varg]

Your 4.10LSD is going to traction limit you, I went down in ratio immediately after M20 swapping because the power was useless in 2nd gear, and I had to pedal it the whole time. If you want to see how it all goes together with AC when not using a kit, take a look at my build thread, I have one of the few turbo E30s with AC. As for brakes I don't think you need a BBK. You're in flatland like me and unless you're going to track the car, you're not going to overheat the brakes. Not that there's a point in tracking a 350whp E30 without a ton of other mods so the power is actually useful.

-Use an eBay FX clutch to save $$, they're great and I don't see them as a compromise.

In my experience, avoid cheap clutches, especially kevlar ones if you want to ignore me and buy cheap anyway. Years ago my FX/F1 kevlar clutch became "sticky" as it warmed up and would not disengage from the flywheel when the pressure plate pulled back. Since that happened to me years ago, I have heard of it happening to others. Might not happen with weekend toy cars that see hardly any miles, but I was daily driving so the car was getting tested in all conditions.

Lesson learned: Clutches are a huge pain in the ass when they go wrong, so buy a good one instead of chinabay stuff.

[moatilliatta]

Terrible.

[AWDBOB]

This is all super helpful!

I did reach out and Jake gave me some great info, thanks Jake!

Some follow up questions I have:

1. I've removed the cam from my list, what about the rocker arms and valve springs? Will I be okay with just the new stock head?
2. Do you have a link to the knockoff FX400? Or the brand name?
3. What's the benefit of the LS Coil Kit vs. the Wasted Spark setup?

My general rule of thumb is based on cam wear. If the cam isn't worn and the rockers match the cam I typically leave them. If you replace the rockers it's best practice to replace the cam as well and vice versa.

The cheapies people typically use are "FXRacing" brand, sold by gripforce-clutches on fleebay. Jake has the kevlar one in his car with a stock pressure plate. His car makes a little over 300whp and it's held up well.

He'll have a more educated answer than I will re: LS coils/WS

Your 4.10LSD is going to traction limit you, I went down in ratio immediately after M20 swapping because the power was useless in 2nd gear, and I had to pedal it the whole time. If you want to see how it all goes together with AC when not using a kit, take a look at my build thread, I have one of the few turbo E30s with AC. As for brakes I don't think you need a BBK. You're in flatland like me and unless you're going to track the car, you're not going to overheat the brakes. Not that there's a point in tracking a 350whp E30 without a ton of other mods so the power is actually useful.



In my experience, avoid cheap clutches, especially kevlar ones if you want to ignore me and buy cheap anyway. Years ago my FX/F1 kevlar clutch became "sticky" as it warmed up and would not disengage from the flywheel when the pressure plate pulled back. Since that happened to me years ago, I have heard of it happening to others. Might not happen with weekend toy cars that see hardly any miles, but I was daily driving so the car was getting tested in all conditions.

Lesson learned: Clutches are a huge pain in the ass when they go wrong, so buy a good one instead of chinabay stuff.

Good intel- I know many folks who have used the FX clutches over the years and haven't heard a bad account until now. But I'm sure no one I know has put them through DD paces. Like Garagistic parts..... they can't break if they're always in the trunk waiting to be installed

You've had good luck with Clutchmasters?

[AWDBOB]

Terrible.

you still planning to turbo your home furnace and work van?

[varg]

You've had good luck with Clutchmasters?

The only clutchmasters I've had is the 850 twin disc in my wagon. The spec stage 3+ in my E30 wouldn't disengage fully when new and now occasionally causes a vibration that goes away when I clutch in and back out slowly. It's easiest to reproduce that by popping the clutch in neutral, it'll almost always vibrate after that. I have a UUC lightweight flywheel and M5 clutch conversion waiting to go in my E30, probably this winter and if it's any good it'll be my top recommendation because it's pretty cost effective and the lightweight setup in my wagon is just so nice. Eminently blippable.

I do not abuse my cars, but I was always notoriously hard on parts because of the long commutes and daily driving. If something is going to rear its head with time it'll show up sooner with someone who is putting as many miles in a month on an old car as most do in a year. Now I have a much shorter commute, and I'm putting hardly any miles on my cars.

[NathanR]

• On the note of a clutch, I don't think I mind spending an extra couple hundred just to avoid needing to do it again if the eBay clutch gives up. In that case, is the FX400 appropriate? Or should I do like an FX300/FX350 or others? The car is daily driven-ish when the sun's out, I probably drive it 4-5k mi/year.
• On intercooler mounting, I assume I'll need to delete the oil cooler?
• While I’m at it, should I be planning on adding a catch can here?
• Don’t wanna let the LS coils vs wasted spark question die off here, any feedback on this one?
• Final dumb question for the day - how does timing work after the distributor is deleted?

[varg]

Timing works the same way as it does now, it's controlled by the ECU, the distributor is only there because there's one coil. Either wasted spark or sequential LS coils will be fine with this kind of power goal, choose what works out for you i.e. if you don't want to do some wiring use whatever there is a kit for. FWIW, you can run LS coils in the wasted spark configuration too, the difference between the two is one requires a cam sensor, and one doesn't. One configuration fires two coils at once, one fires one at a time. You don't have to delete the oil cooler, you can mount an aftermarket one somewhere. I have my stock one mounted to my core support, and it does still do some cooling there believe it or not. I've confirmed with a thermal camera.