MK1 MR-2 motor rebuild help!

[sgtnavytiger]

Hello,
I just brought an MK1 Mr-2 motor and was planning on rebuilding it. I had several questions, and was hoping someone here would know a little more than I do! I was planning on boring .20 mm over, and installing new wiseco pistons, after first having the crank ground, connecting rods ground and re-trued, flywheel inspected(?), and all balanced. Next would be a header, a great man I know from Canada is going to hook me up with one, not sure on brand just yet. Soon after, a port and polish, valve seals inspected and possibly all reground. Then, I was going to shop for bigger camshafts. I want this car to still be fairly reliable, and street-drivable. So, that brings me to any suggestions for camshafts. Thus far, I have found ones with a 8.1mm lift, with a 265 through a 275 degree duration. (found at www.andysautosport.com from HKS) Finally, the seemingly hard question, what should i do for injectors? The smallest i have found was 550CC injectors, however I have read that the stock 4age motor came with 185CC injectors. (550cc just felt a little drastic)
Three quick, easy questions left. Is there any need for an e-manage (or any piggy back ECU system) system for the fuel system change? Will I need larger injectors and a different ECU to increase fuel flow, or will the larger injectors do this for me? And finally, will I need a larger AFM for the increased amount of air? -Why did we leave carbs?? HA!

Thanks for ANY input!
Benjamin J Harper

Check this site http://www.geocities.com/MotorCity/lane/1231/afm.html
Also, I've heard from that Supra injectors may work?
Please someone straighten me out! Thanks!

[ModifierMR]

First may I suggest you bleed your coolant. It is the end all fix all problem solver.

lol Just kidding, but seroiusly

Originally Posted by sgtnavytiger

Hello,
Finally, the seemingly hard question, what should i do for injectors? The smallest i have found was 550CC injectors, however I have read that the stock 4age motor came with 185CC injectors. (550cc just felt a little drastic)

Supra Injectors will work. Although I would go to crazy with fuel delivery. I mean if you were doing forced induction I could understand why. But you are keeping it N/A Correct?

Three quick, easy questions left. Is there any need for an e-manage (or any piggy back ECU system) system for the fuel system change? Will I need larger injectors and a different ECU to increase fuel flow, or will the larger injectors do this for me?

If you upgrade to bigger injectors you will need a some sort of fuel management piggy back setup. But if you are completley tuning and building this motor from the ground Up I suggest saving up and finding yourself a decent cheap Standalone ECU. Something you can completley program and you can set up your injectores to fire as you see fit.

And finally, will I need a larger AFM for the increased amount of air? -Why did we leave carbs?? HA!

I dont think you need a bigger AFM but like I said, having a Standalone ECU will make things simpler and less hacked. That is if you can program. lol

[JDM'ized]

Originally Posted by ModifierMR

First may I suggest you bleed your coolant. It is the end all fix all problem solver.

lol Just kidding, but seroiusly




Supra Injectors will work. Although I would go to crazy with fuel delivery. I mean if you were doing forced induction I could understand why. But you are keeping it N/A Correct?



If you upgrade to bigger injectors you will need a some sort of fuel management piggy back setup. But if you are completley tuning and building this motor from the ground Up I suggest saving up and finding yourself a decent cheap Standalone ECU. Something you can completley program and you can set up your injectores to fire as you see fit.



I dont think you need a bigger AFM but like I said, having a Standalone ECU will make things simpler and less hacked. That is if you can program. lol

I agree.
As far as the injectors....I wouldn't go bigger than 370cc (if you're planning to put down 200-250 hp).....370cc will do the job.
Going with 550cc (like mentioned above, is overkill, and hard to tune it if your engine won't make more than 250 hp)....unless you go turbo and make at least 300 hp.
E-management works fine, but standalone are always a plus.
I got an Haltech E6X which I like a lot, and it's not that difficult to wire up.
Good luck.
Alex

[sgtnavytiger]

Thanks for the info guys! So, how big are the supra injectors?
Yes, this motor will be naturally aspirated.
I'm sure I could learn to program an ecu however; It may not be worth the risk.
I think I may go with the Greddy E-manage system.
What about the, I think it's 4AGZE, the supercharged 4age motor's injectors?
Any opinions on cams and pistons?
Thanks again

[MR2Jedi]

Originally Posted by ModifierMR

First may I suggest you bleed your coolant. It is the end all fix all problem solver.

lol Just kidding, but seroiusly




lol

[sgtnavytiger]

What about a small turbo charger? Any thoughts on this?!
And I'm not sure how much HP it would make... not really sure how much this combo would make...

[JDM'ized]

Originally Posted by sgtnavytiger

Thanks for the info guys! So, how big are the supra injectors?
Yes, this motor will be naturally aspirated.
I'm sure I could learn to program an ecu however; It may not be worth the risk.
I think I may go with the Greddy E-manage system.
What about the, I think it's 4AGZE, the supercharged 4age motor's injectors?
Any opinions on cams and pistons?
Thanks again

Don't quote me on that....but I think the Tacoma 2RZ injectors are 320cc (I know it's irrelevant....but it helps me thinking....).....Supra have to be bigger than that.....so maybe around 350cc, or in that neighborhood (again, don't quote me on that)....but if that's the case, they should work for your HP goal.
As far as pistons. I went with Arias (I'm too a N/A die-hard). I ordered a set of 12.5:1 compression and have them coat the dome and skirt for heat and friction respectively.
Cams.....there are just so many good companies out there, you can't go wrong with proven HKS. Look into something like 272/264 duration. They should give you some good mid-range and a bit of top end too.
How about BC ? Do they make anything for the MR2 ?.....or even Greddy.
Web Cams also should make something for your engine.
When considering aftermarket cams, do your HW...specs of aftermarket cams make the whole difference in the worlds. If you have huge lobes and cams that have a lot of duration and high lifts, they make a lot of power up top, and sacrificing some bottom end....always choose wise, so you don't compromise bottom end and mid range.
Good luck.
Alex

[toyotaspeed90]

7mgte's are top feed and 440cc/min
2jz-gte's are 550cc/min and side feed

4agze's are 365cc/min

4age smallport have 250cc/min... only downside is that they are high ohm and you will need to remove the resistor pack.

stock bigports are 215cc/min...

however.... the fuel pump is run at only around 70% or so.... the 4age pump in the aw11 can easily power lower boost (like an ae101 4agze at 10psi) and still be running super rich. You could keep the stock injectors and go with an aftermarket fuel pressure regulator and rise the rate.

using hks 272/273 with a bigport head and otherwise pretty stock you won't see a huge gain in power... easily under 150 at the wheels. stock puts down (in their aged state) around 90-105whp.

[sgtnavytiger]

Hmm, well after some thought, i think i am going to go turbo. I plan on using a garrett T25. My father and i are going to build the downpipe, manifold, and whatever else we need. I'm will soon be ordering 4 new arias 8.6 comp ratio pistons. The motor will have the bore fitted to this pistons along with a line hone. I'm not sure what i am going to get done as far as headwork. Maybe over sized valves and larger camshafts. The fuel system is still a problem. I have found a set of 7mge supra injectors, green top 315 cc. But i think that they are high impedance, what would i have to do to make these injectors work? also are there any physical limitations? Finally, do i need an AFM that will "see" boost?
Please, let me know what you guys think. Thanks a ton!

[JDM'ized]

If you read above, Toyotaspeed90 says that with high impedance injectors you have to remove the resistor pack...
As far as your selection for the injectors, RC makes all you can think of....size, low/ high impedance, lenght, everything. Give 'em a call and see what's up.

As far as the boost AMF...I like to have a gauge that monitors the fuel pressure....especially when you tune it on the dyno. You can screw it in on the AFPR....like an Aeromotive for instance.

For the head, since you're gonna tear it apart...you might as well port and polish it at least, and if you have some extra cash, that's the time you want to fit in some nice cams along with adjustable cam gears so you can fine tune the timing better.
Bigger valves are always a plus...

[toyotaspeed90]

there's no reason to port and polish a 4ag head... they have a factory 3-angle valve grind.... the bigport easily breathes enough air....

if you plan to go turbo.... the only way to use the stock ecu is to "ghetto" mod it, and it WILL BE UNRELIABLE. To do this, you must swap the injectors to something like the 365's or larger..... you will also need to purchase a hobbs pressure switch... when it reads boost it needs to turn the cold start injector on for excess fuel. You will also have to re-located your AFM to pre-turbo. The stock afm will NOT read correctly after the turbo.

if you plan to go turbo and want to do it right, go with an aftermarket ecu... at least a band aid computer (aka piggy back) that will give you more flexibility with changing the pulsewidths of the injectors.

on my 4agte build, i'm using a stock ae101 4agze (s/c stuff pulled off), a CT20A turbo, supra 440 injectors, and megasquirt.

[JDM'ized]

Originally Posted by toyotaspeed90

there's no reason to port and polish a 4ag head... they have a factory 3-angle valve grind.... the bigport easily breathes enough air....

How rough is the casting of the combustion chamber and intake/ exhaust?
Maybe the head already flows super well, but smoothing out the imperfection....there is nothing wrong with that....

Originally Posted by toyotaspeed90

...on my 4agte build, i'm using a stock ae101 4agze (s/c stuff pulled off), a CT20A turbo, supra 440 injectors, and megasquirt.

I thought the 2JZ-GET had 550cc injectors...

[toyotaspeed90]

Originally Posted by JDM'ized

How rough is the casting of the combustion chamber and intake/ exhaust?
Maybe the head already flows super well, but smoothing out the imperfection....there is nothing wrong with that....

I thought the 2JZ-GET had 550cc injectors...

read my post above.......

the 2jzgte does have 550's... but they are sidefeed and in no-way usable in the 4age with a stock fuel rail.

the 7mgte has 440's that are top feed

[JDM'ized]

I see....Thanks for the info's