Can I do a staged m20 build? ITB, Stroker, Turbo.

[Mastrcruse]

I’m listening, watching YouTube videos, and researching on the forums and want to keep the m20 in my e30. I’ve been a researching a stroker, ITB, turob’d m20. I don’t have a power goal in mind but something that is “somewhat” reliable and “easiest” maintenance with a balance of power. Maybe those 3 things plus reliability and ‘easy’ maintenance don’t go together. I’ve read quite a bit and there are so many options I think I was more confused afterward than I was before.

If I wanted to do a staged build and “grow” the motor, what would be the sequence of events? I was thinking 40MM RHD-E kit, stroker kit (2nd but not sure what size), and turbo kit 3rd.

I nearly pulled the trigger on ITB’s but wanted to start collecting advice on an overall build so I don’t have to redo stuff down the road (or at least limit it).

Honestly, I’m probably biting off more than I can chew but maybe I’m over complicating things.

i was looking at...
IE or Bimmerheads stroker kit
RHD-E ITB 40mm kit
TCD turbo kit

I guess just to add - this isn’t a daily but it’ll be used 2-3 times a week for something fun to do. I could do a swap but I’ve always loved the pure sound of the m20. So maybe all that is overkill, most likely is, so if there’s something that people suggest against - please feel free to share.

[digger]

start with a solid bottom end and standalone computer. the topend stuff including inductions and exhaust is relatively easier to swap and build up later without removing the whole engine

[e30davie]

Yer get the bottom end and head done with stock everything else and then get the aftermarket ecu installed, wired, and running reliably in "end game" configuration. and in my opinion that looks like correctly sized modern injectors for your turbo, distributor less ignition with modern ignition coils, wide band feedback for fuel trim and dialed in cold start, warm up enrichment, air temp correction, and acceleration enrichment and get the thing running better than stock.

Then add your ITBs and turbo in 2 stages. ITBs first. then turbo.

You will thank yourself for getting the ecu sorted when you added the ITBs and turbo. Cuase you will only be dealing with mechanical issues (leaks etc) not trying to work out why the ECU wont work properly.

[AWDBOB]

Echo all of the above. I’m doing it right now. Do the bottom end/top end first in one shot, and get the standalone in once the engine is running good.

Consider this:

I would either do ITBs or turbo, not both.

The RHD manifold does not seal well at all with boost, and if you build your turbo setup properly the difference in transient response between awesome turbo kit - no ITB and awesome turbo kit - w/ ITB will be negligible (surely not $2k worth of a difference)

If you go turbo, spend your ITB money on a proper twin scroll manifold and a proper turbo (think BW EFR or GTX3676) and you will be much better off in various ways.

Deciding up front also allows you to cater your engine configuration to your end game plan.

For example:

1) unless you run e85 or meth, I wouldn’t run 10.5:1 comp with boost, but that’d be perfect NA.
2) If you’re going turbo I’d be hesitant to run 86mm bore with all the added cylinder pressure, but I’d you're staying NA it’s no biggie
3) if you’re going turbo vs NA your cam choice will be very different.
4) If you’re going turbo it’s not logical to get a nice set of headers built and modified to fit your exhaust, but a nice set of headers are essential for a proper NA build

Be HONEST about your end goals. Many folks build cars around what they hope it to be someday, and build what ends up being a super mediocre NA setup cuz “someday they’ll turbo it” but never do, when for the same $$ they could’ve been honest and said “I probably won’t go turbo” and built an NA focused build for similar $$ that would’ve net in a much higher fun factor

[AWDBOB]

Echo all of the above. I’m doing it right now. Do the bottom end/top end first in one shot, and get the standalone in once the engine is running good.

Consider this:

I would either do ITBs or turbo, not both.

The RHD manifold does not seal well at all with boost, and if you build your turbo setup properly the difference in transient response between awesome turbo kit - no ITB and awesome turbo kit - w/ ITB will be negligible (surely not $2k worth of a difference)

If you go turbo, spend your ITB money on a proper twin scroll manifold and a proper turbo (think BW EFR or GTX3676) and you will be much better off in various ways.

Deciding up front also allows you to cater your engine configuration to your end game plan.

For example:

1) unless you run e85 or meth, I wouldn’t run 10.5:1 comp with boost, but that’d be perfect NA.
2) If you’re going turbo I’d be hesitant to run 86mm bore with all the added cylinder pressure, but I’d you're staying NA it’s no biggie
3) if you’re going turbo vs NA your cam choice will be very different.
4) If you’re going turbo it’s not logical to get a nice set of headers built and modified to fit your exhaust, but a nice set of headers are essential for a proper NA build

Be HONEST about your end goals. Many folks build cars around what they hope it to be someday, and build what ends up being a super mediocre NA setup cuz “someday they’ll turbo it” but never do, when for the same $$ they could’ve been honest and said “I probably won’t go turbo” and built an NA focused build for similar $$ that would’ve net in a much higher fun factor

[Mastrcruse]

start with a solid bottom end and standalone computer. the topend stuff including inductions and exhaust is relatively easier to swap and build up later without removing the whole engine

Sorry for my ignorance. Are you both suggesting stroker first? Or just building a monster bottom end w/ megasquirt (or another suggestion?) and OEM top end?

I need to read more about what’s go to for the bottoms end. And if someone can build me one that’ll suit my needs of growth. I honestly don’t know about boost - but Stroker and ITBS tickle my fancy.

[Mastrcruse]

Echo all of the above. I’m doing it right now. Do the bottom end/top end first in one shot, and get the standalone in once the engine is running good.

Consider this:

I would either do ITBs or turbo, not both.

The RHD manifold does not seal well at all with boost, and if you build your turbo setup properly the difference in transient response between awesome turbo kit - no ITB and awesome turbo kit - w/ ITB will be negligible (surely not $2k worth of a difference)

If you go turbo, spend your ITB money on a proper twin scroll manifold and a proper turbo (think BW EFR or GTX3676) and you will be much better off in various ways.

Deciding up front also allows you to cater your engine configuration to your end game plan.

For example:

1) unless you run e85 or meth, I wouldn’t run 10.5:1 comp with boost, but that’d be perfect NA.
2) If you’re going turbo I’d be hesitant to run 86mm bore with all the added cylinder pressure, but I’d you're staying NA it’s no biggie
3) if you’re going turbo vs NA your cam choice will be very different.
4) If you’re going turbo it’s not logical to get a nice set of headers built and modified to fit your exhaust, but a nice set of headers are essential for a proper NA build

Be HONEST about your end goals. Many folks build cars around what they hope it to be someday, and build what ends up being a super mediocre NA setup cuz “someday they’ll turbo it” but never do, when for the same $$ they could’ve been honest and said “I probably won’t go turbo” and built an NA focused build for similar $$ that would’ve net in a much higher fun factor

I think what you are saying is pretty spot on. I’m very on the fence about boost and realistically, wont boost it. I feel boosting means a lot more maintenance and issues that could/will arise. I could be talked out of any of this stuff honestly. I want the fun factor and love the sound of an opened up M20 but also don’t want to hate myself cause I’m working on it more than I’m driving it.

Is there a shop/vendor that is known for these builds and can walk me through my options? Bimmerheads? Be good to have someone walk me through, one that has experience, the options. Like you mentioned - great advice. Thanks

[AWDBOB]

I think what you are saying is pretty spot on. I’m very on the fence about boost and realistically, wont boost it. I feel boosting means a lot more maintenance and issues that could/will arise. I could be talked out of any of this stuff honestly. I want the fun factor and love the sound of an opened up M20 but also don’t want to hate myself cause I’m working on it more than I’m driving it.

Is there a shop/vendor that is known for these builds and can walk me through my options? Bimmerheads?

ForcedFirebird 100%- his business is WOTTech. And being honest with that up front will help you get a car you REALLY can enjoy, not one you sell because you feel like you have to boost it but don't want to.

https://www.facebook.com/WOT-Tech-356741317707642/

[Mastrcruse]

Taking into account fun factor, reliability, and maintenance (plus this is a street cruiser) would the recommendations change? I guess I ask that cause when I think of turbos - unreliable and lots of maintenance come to mind.

If i think what I want, it would be something that pulls hard (up to cruising speed), sounds amazing, is reliable, and has good manners at cruising speed. Something that a lot of fun for spirited driving and cruising.

[SkiFree]

When I developed the 2.9L Ultimate Street Stroker kit, (John) ForcedFirebird and Matt/Shant (Bimmerheads) were both very much in the loop.

[digger]

Sorry for my ignorance. Are you both suggesting stroker first? Or just building a monster bottom end w/ megasquirt (or another suggestion?) and OEM top end?

I need to read more about what’s go to for the bottoms end. And if someone can build me one that’ll suit my needs of growth. I honestly don’t know about boost - but Stroker and ITBS tickle my fancy.

if at the end of the day you are wanting a stroker then yes a stroker bottom end first which is the so called foundation.

maybe you could tell us some more about what kind of characteristics you want with the engine? as there are strokers and there are strokers (lots of permutations and combinations)

[Elysian]

One thing I don't think has been mentioned... If your goal is turbo, you have to have a larger ring gap than NA... So during the motor build, if you know you'll turbo then I'd think it's probably best to gap for turbo.

[Mastrcruse]

if at the end of the day you are wanting a stroker then yes a stroker bottom end first which is the so called foundation.

maybe you could tell us some more about what kind of characteristics you want with the engine? as there are strokers and there are strokers (lots of permutations and combinations)

Thanks! I honestly don’t know if a stroker is the right thing. I’d like the fun factor to be high. A car that pulls hard and scoots until I get up to cruising speed. It won’t need to go above 80mph (express lanes here) but putting my ass in the seat is the most fun to me. I’d like something that sounds good (not SUPER obnoxious but I think this depends on exhaust), period correct is also something I want. But since most of its life will be just cruising, something with smooth power and drivability is something I’d like to achieve. Drivability, reliability, fun factor, and sounds amazing! Doesn’t have to be a 150mph car. It could be a holy shit 0-60 and be just fine.

I bet I’m not really helping.

[digger]

By the sounds of it you want a stroker then nothing crazy but something that can get the car moving at low rpm. A smaller engine will make about the same peak hp but need more revs to do so, meaning you’ll have to work harder (more revs and shorter gearing) to get it moving. At legal speeds a torquier motor will usually outperform a smaller peakier engine even if it has slightly more power as the average power / area under the curve comes into play not just the peak since the lower gears are spaced further part . At higher speeds you can keep the smaller engine on the boil better as the gears are closer spaced the higher up you go thats why drag racing you only need a power band of 2000 rpm or so.