New to the Mk3 not supras.

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Velocityfreak

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May 28, 2009
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So im new to the mk3, im picking up a 87 turbo next week. Aside from fixing the mechanical issues and bringing it all back to stock, getting it perfect like the way it was running from the factory, I want to do some baseline modification for future upgrades.

What should be my first mods... I was thinking of going with the Lex AFM and 550s, but at the same time those feel like piggybacks even though they could be used later down the road, it seems like they are a roadblock eventually.

I dont want to mess around with small mods and waste money. What if I bought a megasquirt v2 3.0, and got that up and running before I put on anything else and got a baseline to work off of. Would it be wise to just get a base tune off of a stock mk3, then mods could be tuned accordingly? Saviing the base maps as I go along, Would a megasquirt be a good investment for the first serious mod?

Whats the most cost effective way to reach 450 - 500 HP? Im eventually thinking ceramic BB turbo too, but thats a bit a ways a way.

Supposidely its a JDM engine, but i dont think that matters at all, unless they torque the HG bolts tighter in Japan.
 
got_boosted

got_boosted

I need a turbo! >:(
Mar 3, 2006
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Sounds like you need to do a little bit of reading in the tech section.

First off, 550cc injectors and Lex AFM are a GREAT combo and will support over 400whp (lots of power for most people), and to make it safely over 500whp you will need lots of things. To my knowledge, you'll need forged pistons and a metal headgasket just to get started. The 550's will probably be too small. If you don't have an upgraded fuel pump for 400whp, you'll need one now, along with an AFPR. An aftermarked turbo will be a must. CTs aren't quite big enough, and you'll need to budget $500-$600 for a decent clutch. If you cut corners with those goals, you'll end up paying more in the long run.

Welcome to the MKIII Supra. They're by far my favorite car that doesn't say Carrera GT3 or Lotus on it. I've been doing this for years now, and my budget build is still about $5-6,000 (including the car for $1,500) for a reliable 500whp car from the ground up doing all my own work. (I chose to start with a 2JZ-GE this time around, but a well-built 7M will be about the same price as doing the swap, or cheaper if you can do a lot of work yourself and get a good deal on parts.)

HTH

Collin
 
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mirage83

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My opinion (fwiw) would be to start with the exhaust and then move on to other things. Big return performance-wise for a relatively small investment right there, and a quality 3" setup will be fine for whatever else you decide to upgrade on the engine later.

Before I went to a larger turbo I'd make sure my engine and supporting equipment (lex AFM, 550+ injectors, etc) was already in place and in good condition.
 
Keros

Keros

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Mar 16, 2007
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The Lex/550 mod is a great idea for a strong 7M... just remember the key word: strong. If there's a flaw in your motor, boosting the crap out of it will find it and exploit (read: explode) it.

Anyway, my understanding of the situation is that a standard CT26 with a Lex/550 mod cannot out-flow the fuel pump (if it's in good shape), and thusly your turbo will die when you crank the boost as opposed to the engine. The 57 trim and any bigger CT26 rebuilds, the same cannot be said. Adding the Lex/550 mod effectively raises the fuel cut limit by 25%, however, if there is not 25% more fuel effectively available, something is going to give... and it'll likely be chunks of pistons out the exhaust ports.

My point is that if you have a stock CT26, you could get the Lex/550 mod and keep everything else as-is and run 14psi. Get an electronic boost controller and run the shortest possible length of vacuum hose to the selenoid then the wastegate to prevent overboost... and call it a day for a while and focus on other things.

I wouldn't expect a CT26 to last long doing that, so when it dies you'll be able to go MAFT-pro, MS, or any other tuning device of your choice, for finetuning fuel at more than 400hp. The Lex/550 combo CAN do it alone... but it isn't a good idea... you should use a piggyback of some sort to aid fuel control. Of course, upgrade the fuel pump and various other fuel mods. IMHO, that's the way to go to get used to the power and upgrade things like suspension, tires, brakes, ect... all requirements for handling the power you'll be making on a bigger turbo. The stock CT26 is more than capable of making tires into smoke.

It is of value to know that the JDM 7M does not have provisions for EGR, and thus should either have a JDM ECU installed or the USDM EGR system retrofitted. Otherwise should you end up in a high load, low RPM situation, there's a possibility of pre-detonation.
 
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Velocityfreak

New Member
May 28, 2009
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New Hampshire
Keros;1334037 said:
The Lex/550 mod is a great idea for a strong 7M... just remember the key word: strong. If there's a flaw in your motor, boosting the crap out of it will find it and exploit (read: explode) it.

Anyway, my understanding of the situation is that a standard CT26 with a Lex/550 mod cannot out-flow the fuel pump (if it's in good shape), and thusly your turbo will die when you crank the boost as opposed to the engine. The 57 trim and any bigger CT26 rebuilds, the same cannot be said. Adding the Lex/550 mod effectively raises the fuel cut limit by 25%, however, if there is not 25% more fuel effectively available, something is going to give... and it'll likely be chunks of pistons out the exhaust ports.

My point is that if you have a stock CT26, you could get the Lex/550 mod and keep everything else as-is and run 14psi. Get an electronic boost controller and run the shortest possible length of vacuum hose to the selenoid then the wastegate to prevent overboost... and call it a day for a while and focus on other things.

I wouldn't expect a CT26 to last long doing that, so when it dies you'll be able to go MAFT-pro, MS, or any other tuning device of your choice, for finetuning fuel at more than 400hp. The Lex/550 combo CAN do it alone... but it isn't a good idea... you should use a piggyback of some sort to aid fuel control. Of course, upgrade the fuel pump and various other fuel mods. IMHO, that's the way to go to get used to the power and upgrade things like suspension, tires, brakes, ect... all requirements for handling the power you'll be making on a bigger turbo. The stock CT26 is more than capable of making tires into smoke.

It is of value to know that the JDM 7M does not have provisions for EGR, and thus should either have a JDM ECU installed or the USDM EGR system retrofitted. Otherwise should you end up in a high load, low RPM situation, there's a possibility of pre-detonation.
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Thanks that ECU information is very valuable, I will make sure it is the JDM ecu, I believe the entire loom was swapped but I will certainly have to make sure. I believe there was an EGR on there, but it looked odd, as the EGR vacuum modulator only had 2 hoses coming from it. I thought there were 3 on the US EGR vacuum modulator?

Perhaps, it would benefit my setup initially to run the JDM ecu before the MegaSqirt addition, as it would be dumping extra fuel at idle, because of the lack of EGR, it would allow better emissions and fuel economy, and fuel map if I also include an EGR, as i could lower the idle a bit, and the ECU should see that its running rich and pull back some of the fuel. Is there any difference between the JDM engines and US engines in terms of power?
 
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Velocityfreak

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jetjock;1334554 said:
What would a lack of EGR cause it to be dumping extra fuel at idle?
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because the air volume that the engine needs to stay running, the EGR is circulating exhaust wastegas with no oxygen content.

With a jap engine and lack of egr, the engine is still breathing X amount of oxygen air at 1000 RPM, vs a US engine is breathing Y amount of oxygen air + EGR amount which equals X.

X is both the same
In japan its strictly X (lack of EGR) (higher oxygen count)
IN US you have Y amount which is less than X, plus the addition of EGR waste gas, the waste gas fills up volume to run cleaner. So Y + EGR = X (lower oxygen count) Remember there is no oxygen content in EGR recirc.

you have the same amount of gas leaving in the exhaust pipe but because JDM engines have no EGR, they have a higher oxygen content, the ECU will correct the lean mixture with more gas.

You see now?
 
jetjock

jetjock

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Jul 11, 2005
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Redacted per Title 18 USC Section 798
I'd hardly call that "dumping".

Velocityfreak;1334505 said:
...as it would be dumping extra fuel at idle, because of the lack of EGR, it would allow better emissions and fuel economy...
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So injecting this extra fuel results in *better* emissions and fuel economy? How does injecting more fuel result in using less? And how does the lack of an emissions device result in better emissions? Not that it matters because EGR is *never* active at idle, which is what I was getting at. Therefore both engines in your example would be "lacking" it.

Btw did your dad also tell you this?:

Velocityfreak;1332806 said:
NE is earth / ground.
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Be careful what you wish for...
 
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Velocityfreak

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May 28, 2009
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jetjock;1334918 said:
I'd hardly call that "dumping".



So injecting this extra fuel results in *better* emissions and fuel economy? How does injecting more fuel result in using less? And how does the lack of an emissions device result in better emissions? Not that it matters because EGR is *never* active at idle, which is what I was getting at. Therefore both engines in your example would be "lacking" it.

Btw did your dad also tell you this?:



Be careful what you wish for...
Click to expand...


Sorry Ne is engine revolution sensor, it was off the top of my head.

I mention nothing about lack of EGR resulting in better emissions, if you want this information do the research. All emissions equipment improves emissions.

Actually EGR has partial vacuum at idle (EGR is not Recirculated through valve A), as valve b is open, So you arent totally correct with your assumptions. Valve A which supplies most of the EGR gas is open past idle, but valve B is open during idle, and does actually let exhaust emission/pressure balance through the EGR vacuum modulator. Thats why when you remove the cap to that thing, the filter is always clogged up. Its EGR gas that bypasses and goes into the intake manifold, even though its small there is still EGR gas that enters the intake manifold at idle, have a look at your EGR diagrams again in the BGB.

Yes when you look at the TB at idle the plate physically blocks the EGR port for valve A off. However valve b is still open and feeds directly to the manifold.
 
jdub

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
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Feb 10, 2006
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Velocityfreak;1335066 said:
Sorry Ne is engine revolution sensor, it was off the top of my head.

I mention nothing about lack of EGR resulting in better emissions, if you want this information do the research. All emissions equipment improves emissions.

Actually EGR has partial vacuum at idle (EGR is not Recirculated through valve A), as valve b is open, So you arent totally correct with your assumptions. Valve A which supplies most of the EGR gas is open past idle, but valve B is open during idle, and does actually let exhaust emission/pressure balance through the EGR vacuum modulator. Thats why when you remove the cap to that thing, the filter is always clogged up. Its EGR gas that bypasses and goes into the intake manifold, even though its small there is still EGR gas that enters the intake manifold at idle, have a look at your EGR diagrams again in the BGB.

Yes when you look at the TB at idle the plate physically blocks the EGR port for valve A off. However valve b is still open and feeds directly to the manifold.
Click to expand...


So exactly where did you get this little piece of fiction? Or, did you make it up yourself?

JJ is right (as usual), you have NFI what you're talking about. It would be wise for you to refrain from posting this kind of BS in the Tech sections.
 
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Velocityfreak

New Member
May 28, 2009
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New Hampshire
jetjock;1335232 said:
Crack me up. If Valve A leaves Denver at 5:15 and Valve B leaves Chicago at 9:22 which one will be closer to Des Moines when they pass? :)
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Am I really wrong or did I call you out Jet Jock? The person who never gets called out because he is the one doing the calling, then please explain to me exactly how the EGR system works. And what is its intended purpose, and why when removed the vehicle has more power and gets less MPG.

I am all ears, because you have not reviewed your BGB in a long time, explain why valve B always has vacuum? and Why the exhaust system has pressure build up between the manifold and cat, and there is vacuum in the intake manifold. The pressure difference is seen by the EGR vac modulator. The lines are always connected valve B and are always open on the EGR unless intake vacuum is above 600mmHg, in which case valve B closes off.

Dont be surprised that someone knows more than you, because there will always be someone better than you, and you may have spent years on the forums, but it only takes one comment to light a fire. My suggestion is to acknowledge and move on.

I am over it, I know who is right. Your knowledge precedes me when it comes to electronics, I cant surpass that knowledge, but just be aware you are not always right.
 
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