E30 tuning options

[extski 0]

Hi all,

So I'm wanting some advice on tuning for my M20B27. I've recently had it rebuilt and now that I have it back have found that it has way to much compression, around 230psi. I'm pretty dark about this as the engine is now detonating and the chip that was programmed for the engine previously is now no longer suitable.

I figure I've got a few options:

1. lower the compression by installing a thicker head casket or changing pistons or something similar. I don't really want to go down this route if I can avoid it as I've just spent a fair amount getting the engine built and there's no guarantee that this will lower the compression enough to allow me to tune it.

2. Buy a Link ECU or other after-market computer and try and tune it to allow me to run that high compression. If this would work I'm willing to consider it but I don't really want to have to spend another 3k if I can avoid it.

3. Get the original tuner to try and write a new blank chip on the dyno for me. If this works it'll be the cheapest option but there's no guarantee that it would and if it doesn't then I'm down $1200 with nothing to show for it.

I'd love to know if any one has any ideas about how I could fix this problem.

Thanks in advance.

Angus

[polley 916]

What is your static compression ratio, and where is it detonating (load / rpm)?

[BM WORLD 1283]

just get the ecu remapped , doesn't cost that much

and i am sure he can work with the compression.

add more fuel or pull some timing out etc

try gavin at hi-velocity

call him and ask

http://www.hivelocity.co.nz/

[No name user 379]

im with polley fix before you re-tune it and dont do a re-flash if you have no idea what you've ended up with there's no point spending more money, you can cc the motor without pulling it apart once you know the effective compression then move forward.

Ive tuned a few 2.7 cant say they went any better than a stock 2.5 there's an ecu made here as a complete stand alone called ECS made by the ex founder of link and retails at 1300 thus why don't bother with the re-flash you'll get more for your money and have better control over whats needed.

[Nobimmer 694]

Yep, have looke very hard into the ecs system and as far as bang for buck goes there isn't anything anywhere near it. We are going to run it in our 2 litre car.

[extski 0]

Thanks for your advice guys, have you heard anything about Megasquirt? http://www.msextra.com/

[No name user 379]

Thanks for your advice guys, have you heard anything about Megasquirt? http://www.msextra.com/

no comment

[extski 0]

no comment

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[polley 916]

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I think what he is saying is, its sh*t.

From what I've gathered, they're alright, but comes down to the person installing it. For some reason megasquirt seems to attract idiots who cant wire anything that has more than two wires, and most problems people have with it comes down to they have done a shitty job wiring it in.

Go with whatever your tuner is comfortable with installing / tuning. A megasquirt install is still going to cost $1k+ if you buy everything new, spend an extra thousand dollars and get something with a better build quality and connectors.

Edited June 27, 2012 by polley

[No name user 379]

I think what he is saying is, its sh*t.

From what I've gathered, they're alright, but comes down to the person installing it. For some reason megasquirt seems to attract idiots who cant wire anything that has more than two wires, and most problems people have with it comes down to they have done a shitty job wiring it in.

Go with whatever your tuner is comfortable with installing / tuning. A megasquirt install is still going to cost $1k+ if you buy everything new, spend an extra thousand dollars and get something with a better build quality and connectors.

top answer dude

[skidz 197]

Hi all,

So I'm wanting some advice on tuning for my M20B27. I've recently had it rebuilt and now that I have it back have found that it has way to much compression, around 230psi. I'm pretty dark about this as the engine is now detonating and the chip that was programmed for the engine previously is now no longer suitable.

I figure I've got a few options:

1. lower the compression by installing a thicker head casket or changing pistons or something similar. I don't really want to go down this route if I can avoid it as I've just spent a fair amount getting the engine built and there's no guarantee that this will lower the compression enough to allow me to tune it.

2. Buy a Link ECU or other after-market computer and try and tune it to allow me to run that high compression. If this would work I'm willing to consider it but I don't really want to have to spend another 3k if I can avoid it.

3. Get the original tuner to try and write a new blank chip on the dyno for me. If this works it'll be the cheapest option but there's no guarantee that it would and if it doesn't then I'm down $1200 with nothing to show for it.

I'd love to know if any one has any ideas about how I could fix this problem.

Thanks in advance.

Angus

Angus, how did you end up with such high compression? If you started with a standard 325 motor, installed a 2.7 Crank and rods, and retained the 325i pistons, you would end up with low compression - you need to deck the block. So I am picking you have used the 325 rods, which are longer, to give such high compression figures- if you have done this you are in serious danger of the pistons hitting the head, as well as the valves.

I guess the other option is that you have used the 2.7 rods (same length as 2.0 rods) and decked the block, as per the literature, but have gone too far...

So I would be more concerned about making sure the mechanical side of things is correct before you go any further.

Edited June 27, 2012 by skidz

[extski 0]

Angus, how did you end up with such high compression? If you started with a standard 325 motor, installed a 2.7 Crank and rods, and retained the 325i pistons, you would end up with low compression - you need to deck the block. So I am picking you have used the 325 rods, which are longer, to give such high compression figures- if you have done this you are in serious danger of the pistons hitting the head, as well as the valves.

I guess the other option is that you have used the 2.7 rods (same length as 2.0 rods) and decked the block, as per the literature, but have gone too far...

So I would be more concerned about making sure the mechanical side of things is correct before you go any further.

Hi thanks for your response. The engine is an ETA block. I'm not really sure how the engine builder managed to get such high compression I'm in the process of trying to find out. My guess is that when he was decking the block he's taken too much out. He has so far denied this and as I don't have any measurements from before the rebuild it's almost impossible for me to prove that this is what he's done.

I'm pretty dark about it, but at the end of the day I guess I'll just have to suck it up and learn from the experience. I've decided to go with putting a thicker head gasket in to lower the compression and will then get an ECU to tune it.

I'll let you know how it goes.

[extski 0]

I think what he is saying is, its sh*t.

From what I've gathered, they're alright, but comes down to the person installing it. For some reason megasquirt seems to attract idiots who cant wire anything that has more than two wires, and most problems people have with it comes down to they have done a shitty job wiring it in.

Go with whatever your tuner is comfortable with installing / tuning. A megasquirt install is still going to cost $1k+ if you buy everything new, spend an extra thousand dollars and get something with a better build quality and connectors.

Yeah I get it now. Did a bit of research and have found the same thing, was worth a look though.

Do you know anything about Microtech stuff? Can you recommend a good ECU that would be within my budget of no more than $1000 for the ECU and loom?

If I was to go with a second hand unit, would it be able to be retuned to my car even though it may come from a different make of car?

Sorry for my ignorance on the matter, I'm pretty new to all of this.

Cheers

[polley 916]

I would stay away from microtech for the simple fact that they need to be sent back to the factory and have them reconfigure it if you want to run it on a different engine than it was originally bought for.

Other than that, any aftermarket tuneable computer can be retuned for a different engine as long as it supports the trigger system you will be using and has enough outputs for spark and fuel etc.

You will want a system that can read and decode the 60-2 trigger wheel, using a magnetic sensor.

Do you intend on running the standard distributor? Or convert to sequential, or wastespark?

If you're only looking at spending $1000, you will be best off installing a piggyback ecu. Which will also cut down significantly on tuneing time, and installation time. You could PM crunchy about the MAPECU piggyback, which he knows all about.

[No name user 379]

I would stay away from microtech for the simple fact that they need to be sent back to the factory and have them reconfigure it if you want to run it on a different engine than it was originally bought for.

Other than that, any aftermarket tuneable computer can be retuned for a different engine as long as it supports the trigger system you will be using and has enough outputs for spark and fuel etc.

You will want a system that can read and decode the 60-2 trigger wheel, using a magnetic sensor.

Do you intend on running the standard distributor? Or convert to sequential, or wastespark?

If you're only looking at spending $1000, you will be best off installing a piggyback ecu. Which will also cut down significantly on tuneing time, and installation time. You could PM crunchy about the MAPECU piggyback, which he knows all about.

cheers for the plug but i rather not get into telling about them there's a stigma amongst bmw owners that you cant do certain things thus ive given up posting let them find out the hard way

[extski 0]

I would stay away from microtech for the simple fact that they need to be sent back to the factory and have them reconfigure it if you want to run it on a different engine than it was originally bought for.

Other than that, any aftermarket tuneable computer can be retuned for a different engine as long as it supports the trigger system you will be using and has enough outputs for spark and fuel etc.

You will want a system that can read and decode the 60-2 trigger wheel, using a magnetic sensor.

Do you intend on running the standard distributor? Or convert to sequential, or wastespark?

If you're only looking at spending $1000, you will be best off installing a piggyback ecu. Which will also cut down significantly on tuneing time, and installation time. You could PM crunchy about the MAPECU piggyback, which he knows all about.

Oh real, can they not be tuned by someone like speedtech?

I'll be running the standard distributor.

yeah I've been looking at piggybacks and am definitely still open to that idea.

[skidz 197]

I run a WAR chip in my Race car, cheap to buy, but still $$$ to have tuned. Andre at SpeedTech did a good job though

[polley 916]

Oh real, can they not be tuned by someone like speedtech?

I'll be running the standard distributor.

yeah I've been looking at piggybacks and am definitely still open to that idea.

The microtech's can be tuned by anyone, but first they have to be configured for your engine by microtech. If you intend to install it on a different engine than it was bought for, it will need to be sent back to microtech to be reconfigured, and then you will need to get someone to install and tune it.

Im not sure what they change, if it is hardware or firmware I don't know.

[extski 0]

The microtech's can be tuned by anyone, but first they have to be configured for your engine by microtech. If you intend to install it on a different engine than it was bought for, it will need to be sent back to microtech to be reconfigured, and then you will need to get someone to install and tune it.

Im not sure what they change, if it is hardware or firmware I don't know.

ok thanks, I'll investigate.

[extski 0]

I run a WAR chip in my Race car, cheap to buy, but still $$$ to have tuned. Andre at SpeedTech did a good job though

Hi Stephen, how's it going? Thanks for the input, will probably get the tuning done through Speedtech

[muzza1 0]

Hi Stephen, how's it going? Thanks for the input, will probably get the tuning done through Speedtech

Hi Angus,

What system did you end up with. I'm about to go through the same process with my 2.8 ltr.

Cheers,

Murray