JohnBoy's Turbo Build

[KINGAMR]

It's not a ti, it's a 318is coupe

[RAiMA]

Originally Posted by KINGAMR

It's not a ti, it's a 318is coupe

My bad...

and Diam xxxJohnBoyxxx, I read your whole thread!

[xxxJohnBoyxxx]

Originally Posted by RAiMA

You're a brave man giving the keys to your wife

Been with the wife since 10th grade and I'm 41. She doesn't understand a lot of mechanical things but can drive the $hit out of that car.

She purchased the motor as a gift so she can drive it anytime she wants, I still get nervous when she is out driving it and I never let her take it out bar hopping with her friends...

[xxxJohnBoyxxx]

Well I've got my weekend project on a roll. Megasquirt MS-II on V-3 board. Ordered the 12' cable for easy install and I'm getting ready to open the BMW DME for connections.

Pictures:

[lpcapital]

Thanks for sharing all these info John!!! Good luck with your project...

[Jean H.318TI]

sick sick sick, sorry for the dumb question but why do u need these Megasquirt?

[lpcapital]

Originally Posted by Jean H.318TI

sick sick sick, sorry for the dumb question but why do u need these Megasquirt?

That's an open-source ECU. It will basically run in paralel with the stock ECU to control spark & trim, while the stock ECU will control everything else...

He'll be able to do his own tuning on the fly by connecting the laptop to the Megasquirt through a serial...

At least that's my understaind of the Megasquirt... Originally I thought it was some XXX stuff

[Jean H.318TI]

ohh okay so is like a piggyback, right?

[lpcapital]

Originally Posted by Jean H.318TI

ohh okay so is like a piggyback, right?

My understanding of "piggybacking" is that you use a device between the ECU and either the sensor (e.g. MAF) or the controller (e.g. coils) to intercept the signal and modify it. This means that either the ECU makes decision based on a signal that doesn't reflect the sensor's reading (e.g. when you add a resistor on the IAT to make the ECU think the air is colder than actually is resulting in a rich mixture), or the controller acts on a signal differnet to the one sent by the DME (e.g. you intercept and modify the signal the ECU sends to the injectors such as with the Power Commander).

The Megasquirt actually bypasses the DME: the DME doesn't controll fueling & spark. The Megasquirt controlls it. The Megasquirt get's the signal directly from the various sensors (e.g. MAF, IAT, TPS, crank and cam position) and based on the maps it decides fuel & spark and controlls directly coils & injectors. The maps are changed by connecting the laptop to the Megasquirt through a serial port using a GUI (e.g. MegaTune)

It can be used a stand-alone system, but in John case, he's using it as a hybrid system so he maintains functionlities such as cruise control, A/C, EWS protection and such which are still managed by the BMW DME...

The advantage is that of course you get better tuning, you can do it yourself, maybe he even decide to go with a MAP instead of the MAF for better tuning, I think you can also add the wideband into the Megasquirt to have wideband adaptaiton, he can add features such as overboost protection (you can tune it so that if for whatever reason the MAP reads more than x PSI of boost, it cuts off the injectors...)... Very powerful stuff, if you know how to use it... And John has the track record...

[Jean H.318TI]

ohhh okay thanks for answering my question

[xxxJohnBoyxxx]

lpcapital explained it very well. This is a test DNE since I already have a good running code for the DME on turbo everyday driving eccept one error. Error is adaption value out of range and should be an easy fix by dropping the injector constant a few. Code is 95% completed for OBD-II M44 turbo.

With the Megasquirt involved I can do "Launch Control". Spool the turbo with timing then drop that on launch for a fully spooled turbo run.

Knock sensors work with the MS-II I' using so I can timing retard or limp if it's real bad.

***Ability to use wide-band O2 sensor***

The ability to use a wide-band -vs- a narrow band for tuning and running coditions is a major plus. I think this will make positive change in better exhaust A/F ratio.


I left a lot of stuff out but will post as I add on more functions.


xxxJohnBoyxxx

[xxxJohnBoyxxx]

So I'm pulling a late nighter (took two gritala so I'm hopping). Got the BMW test DME all apart and all Mega to BMW wiring cross-over schematic written down. Hope to start soldering it tomorrow but might hold off to read some more on different setups. This Megasquirt will keep me busy for a while but the end result should be BMW OBD-II DME with tuing from a windows based computer and a bunch of extra stuff the Mega can do



BMW Test DME ready for soldering







Plug end







Bottom of board






Doing everything with standard BMW connections so if the Megasquirt has an issue I just pull over remove it and pop in the BMW DME with modified code that Mark D did for me.

[sam316i]

Just read this whole thread, wow this is some amazing stuff.
Full credit to you and thankyou for sharing.

[Marv17]

[Fagerheim]

hi xxxJohnBoyxxx! awsome project, im going to do a similar turbo project to my ti in the future, but cant afford it right now.
Iv read allmost the whole thread and im going to take alot of information with me when Im starting my build.
Iv seen ppl useing OBX turbo manifoil with Garret GT30 turbos without useing an oilpump at the return lines without problems...

For my project il use OBX manifoil, Garret GT3071R with 0,63 A/R, 550cc injectors, Forged arrow Connecting rods, Forged CP pistons (8,5:1 compression), Vi-Pec engine management, MLS headgasket, Vac Motorsport valve springs and stock crankshaft, not sure what camshafts yet. Planing on running 20-25psi boost. Im also rebuilding most of the engine before I turbo charge it since it has 250000km / 155300miles on it.

Right now im still working on the exterior and interior, removeing rust and such... Respray the car and such...

Thanks for shareing this information! =)