The idea:

Got ahold of MR2 4AG Blue top Engine.. Everything is included,then i mean everything i mean everything all the sensors and etc... it is from my friend car, and it was sitting tin his garage for ever, so he desided to get rid of it.. 150$ for it was too fair >> so im getting it....

The bottom end has some problems but i dont even care, as long as im on the route to convert it to 7AGTE...


The main Question:

Wiring is MAP based, it has all the sensors and etc etc... BUT, im going with Megasquirt and im going with 4 ignition coils (direct ignition from peugeot). Question - what else i should need to make the engine wiring work propertly with this setup?

Optional Question:

Is everything Bolt on with the 7A and 4AG head? power steering and etc? (i dont have air cond so i think this aint a big problem)...
What CR i should get using 4AGZE pistons in 7A block and using 4AG head? I knwo what ignition chamber on 4AG is more flat so less volume and as long as with 7A head i get the 10.8 CR what should i expect witht the Blue top head?

Thanks guys, i really need some info quick, cuz i need to make the desidion about this setup - is it worth all the hastle....

you will need a 2mm h/g using 4agze pistons to get a 9.0:1 cr...

blue top 4ag??? i thought the ae86 was the only one that has a blue top... i thought the mr2 was red top with tvis...

-DMC

Are you going to be running an EDIS-4 setup for ignition?

Mr2 always used the blue top and the supercharged used the small port head. The 4ag has a FAR more domed combustion chamber Vs. the 7a. Your compression will drop dramatically from the 7a-4a head. I'd just use a stock gasket. if you are using 4ag pistons, the compression would probably be around the stock 8.9:1 (unless they are early lower comp pistons)

either way I would use a strong gasket, even if it's the stock size... I know boost hunger. >>

If you are loosing the 4ag ECU completely you will need megasquirt and spark. It's kinda a goofy looking set up (big sensor set up on the crank) but it works like a charm. There is a guy on club4ag that makes pre-assembled plug and play megasquirt and spark ECU's that are tailored to whatever settings you want. He is relatively cheap, and you can use your stock wiring. Even if you want to build the set up by yourself, he woudl be a good person to talk to in case you have any questions.

My only problem with megasquirt is what is going to run all of the little parts of the car the ECU is tied into. That is why I'd never run one on my daily driver. Some people love them though, I just don't have the experiance. Club 4ag has lots though. My advice, make a visit or two.



That is the head from a 4ag formula atlantic. It's milled down and still has more of a combustion chamber than a 7a.

This post has been edited by FallenHero: Mar 23, 2005 - 12:31 PM

Do you mean Megasquirt 'n EDIS? With the latest version of Megasquirt 'n Spark(024 I believe), people have been experimenting with using their stock ignition system with Megasquirt. Megasquirt 'n EDIS requires that a 36-1 trigger wheel to be added to the crank pulley, and then a VR(variable reluctance) sensor be installed very close to the trigger wheel. This is the route that I plan to go...EDIS provides a hotter spark, and then I can ditch my ignitor and coil and distributor, for a cleaner engine bay. >>



What exactly are all the little parts you're referring to that are tied into the ECU? I may have overlooked some stuff, but it appears to me that the only things that the Megasquirt setup doesn't account for currently is the A/C and stop lights idle up, the check engine light, diagnostics connector(which is already removed from my car), and the catalytic converter warning light(my ECU has this pin, but I don't think I've ever read about this warning light on our Celicas...I don't have a cat anyway.) Please, let me know if there's anything I've overlooked. >>

for your megasquirt stuff i have no idea because i'm just going to run the stock 3rd gen ecu with all the DLI ignition stuff connected with the emanager.

i have 3 8.9:1 comp 4agze pistons that are used if you need them

i just bought some 8.0:1 comp pistons with a stock size metal head gasket

i'll get some more info in a second

coom. I'm talking about all the warning lights, accessories (like ac and such), For me, my auto tranny...>>, even things like the cold start.

I'd have to research it to say more. I've never had a reason to though.

-FallenHero+Mar 23, 2005 - 1:30 PM

Ah ok. >> I don't really care too much about losing my warning lights. My A/C will still work, if I ever get my custom lines made, and I believe that the software I'm using will support the A/C idle up enrichment. Cold start enrichment is also handled by Megasquirt. >>

sweet. I only hear good things about megasquirt. When that is the case, most things are generally taken care of. Are you seriously tinking of running one on the silvertop?

The 4ag head basically bolts onto the 7A block. Just use the appropriate headgasket for the head. 4AGZE pistons in a 7A block with a 4AG head, will yeild slightly higher than stock 4AGZ compression... but it will still be fairly low... good for boost anyway. It doesn't matter what the stock harness is/was if you're gonna go with megasquirt. As far as I know... there are only one or two DLI set-ups that work with megasquirt... Ford EDIS, and I think one other. I highly doubt peugot DIS can be set up to work without some modification to Megasquirt. For the most part, "Megasquirt'n'spark" can handle everything that is required to run the engine. "Megasquirt" I believe still needs the to ECU for ignition timing.

As for 4AGE's... "bluetop" and "redtop" are very very inaccurate terms to classify the different 4AG engines. ALL of the AW MR2's had the bigport motor... regardless of the valve cover color/lettering, these are all considered "bigport"... even the 4AGZE. The AE86 all had bigports also. The ONLY cars to have had the smallport, is the AE92 corolla GTS (4AGE and 4AGZE), AE101 Levin (4AGZE), and a few others.