Engine Internals

[87Mitsu]

Hello everyone, this is my first post I just picked up my first Starion ESI R its a 1987. I have a question about the strength of the internals of this motor and how much boost/horsepower can most G54B engines handle before a rebuild with JE pistons? My car only has 89,000 miles on it and the top end of the motor is really clean as I had the valve cover off over the weekend. The car has always ran synthetic oil and it seems to run healthier than my dd. I just don't want to blow the motor or a head gasket when it goes on the dnyno Friday.Thanks for the help.

[Alsandr]

If I remember right, they don't work that great very much above stock boost.

[Preludedude]

its funny...99% of peoples first post is asking how much the stock motor can handle boost wise...

 

Why are you dynoing a stock car? If you are dynoing it because you will be upgrading and want to have numbers that you started with, then Id leave it on stock boost...

[Alsandr]

its funny...99% of peoples first post is asking how much the stock motor can handle boost wise...

 

Why are you dynoing a stock car? If you are dynoing it because you will be upgrading and want to have numbers that you started with, then Id leave it on stock boost...

*I* didn't ask that.

 

The mantra here is 'maintenance before modification.' Get it up and running well before you even THINK about modifying anything.

[Indiana]

A stock car for a dyno run is going to be disappointing. You might see about 150hp. If the head is clean under the valve cover then someone already replaced the head. Its not the headgasket that's the problem its the surface of the BLOCK that will end up being your problem. If its not been milled its not flat there's no if ands or buts about it. You will just end up learning nothing, wasting your money and causing something to break. You'll over rev it, loose the boost reference for the FPR at high rpms and detonate and blow your headgasket or worse. Unless you can already max out the redline with the pedal held to the floor in any gear DO NOT put that car on a dyno. Dyno will tell you nothing.

 

Things don't happen out on the street like they can on a dyno. There is no wind to slow you down. The load isn't the same for deceleration. People usually go to far past redline on a dyno. Your valve springs unless you are 100% sure they are HEAVY DUTY those valves at redline WILL FLOAT. Floating valves screws up your motor being the air pump that it is, not drawing in air as it should, boost gone, not evacuating exhaust as it should and its all bad its not just the valve guides getting ate up when the valves springs wobble and bounce the valves start to wiggle around and don't seat -this is what valve float means. The fuel pressure relies on boost for it to increase and when the boost levels out or goes away at WOT you are in trouble with the wheels not slowing down, the fuel was cut but the rpms stay high and the ignition mechanical advance is STILL there and the boost retard from the vacuum advance is GONE and you detonate or have preignition or both and the best thing that could happen is the head gasket just blows. This happens even with forged pistons and more money put into the car that you thought you could.

 

No one can tell you the limits of the stock pistons because NO ONE has ever found out. You'll hear the rods will take you to 500hp and I know the pistons can take at least 400hp. JE pistons, sounds like you have been reading the BS from TEP? Most don't first ask about JE pistons especially after they just get a car then want to dyno it unless they found TEP because of an internet search engine.

 

Slow down.

[87Mitsu]

Sorry that I did not state why I will be dynoing the car. It will be on the dyno only because I brought the car running rich so I purchased an Apexi SAFC 2 fuel controller to remove that extra fuel the car is only being dynoed so that I can get that running rich problem fixed so the car will be driveable. But I just wanted to know the strength of the stock internals because I was going to buy a boost controller to raise the boost alittle but I wont do that now that I know these motors wont handle that much boost stock. Thanks for all of your help.

[Cobalt60]

Well, you have an '87, which is 7.5psi of boost stock. In '88, the boost was raised to 10.5psi, and I dont believe any supporting mods were done to the engine, though the transmission was built up a little to take the extra power. This suggests to me the motor should be able to handle 10.5psi.

 

I would say take every ones advice and rebuild the motor before you start cranking boost, but I think I have read that on all stock parts you can get to 14 or 15psi, assuming everything is in good shape. Even then Id think you should at least make sure to change the head gasket, and make sure everything is planed properly, etc. Id also want to have a rebuilt TB, maybe bored to 52mm. Stock fuel injectors tend to go bad as well. I think the stock fuel pump can get up to about 14psi, but I think running larger gauge wires to it may be a good idea.

 

Your car is probably in better shape than mine, but after I bought it, Ive probably put over $2k into my car and it still is not ready to be boosted any further than stock.

[Indiana]

NO this is the worst thing you could do. You must first FIX what is wrong. Then you can mod. You are trying to modify a fuel system that has a problem and you can't "mod out" why its rich. If it is incorrect then you have to find out why and its NOT hard to find this out.

 

Simple things, just a couple things plug into the ECU that might cause it to be rich. The MAF and these RARELY go bad but get blamed for being bad far too often because they can't find what is wrong. The air filter is dirty, its the wrong filter and its some cone thing that covers the inlet to the MAF and leaves about 1/8" crack to suck in ALL the air the motor needs to run, the coolant temp sensor plug plugged in wrong to the temp. gauge unit, seldom cases of bad CTS mostly incorrectly thought to be bad from not including the resistance of the LEADS to your volt meter first then adding those to what the sensor shows, the 20+ year old injectors being just plain dirty and needing 40.00 spent to clean them ( www.witchhunter.com for example), a leaking BOV, an intercooler hose that appear connected and has a tight clamp but its not even on the end of the tube but just barely and it moves away from that as you drive.

 

Ok, how many sensors could be bad that cause the fuel mix to be rich? Just one, the CTS and if you suspect its bad just UNPLUG IT.

 

What's next? Dirty injectors, that's simple have them cleaned.

 

The rest? Leaks in the intercooler plumbing.

 

 

Next, it might be the cam timing off, it might be fouled spark plugs. Many times someone buy some fancy pretty package tiny electrode plug for a modern engine that makes this motor run like crap because they foul out.

 

Too high fuel pressure. If your return line is clogged, restricted or mashed there's a possible reason for being too rich and you'll have to put a gauge on the TB to see this or just anywhere in that return hose off the throttlebody and it should be ~38psi. There is a test port to activate the fuel pump over in front of the cruise actuator its a single plug dangling from the harness and it may still have a cap on it, just run a jumper from the positive battery cable to it and the pump will run. Incorrect ignition timing, timing not set using a timing light but just a guess and used to set idle -very bad idea. The vacuum adv. not working, it increases timing under vacuum load but also decreases for boost pressure. This is the only car I know of that uses that type of vacuum advance unit and they are usually bad and leaking and need replaced, about 65.00 any auto parts store.

 

None of these get fixed with an SAFC or MAFT or on a dyno. That's like using an air freshener in a toilet its is just camouflaged crap. You need to eliminate the source of the problem.

 

You can download the service manual for free, read the faq about setting the TPS and ISC screw for idle. There's some help pages of pictures if you find them still available.

 

You can find some of those topics in the links down the right side of the index page on my site too, there are additional links from those and under all the names of peoples cars below that, if its blue its a link:

 

www.b2600turbo.com

[87Mitsu]

Thank you vary much for all of the info Indiana and everyone else who has replied I really appreciate it. But I guess I joined the forum a little too late, I wish I had known this info before I purchased the SAFC.Now I will look into all of the possible problems the fuel system could be having. I only purchased the SAFC because the tuner said this would be the most affective and cheapest way to solve the running rich issue without having to replace a bunch of parts and trial and error and spend a lot of money.

[Indiana]

A dead CTS or one plugged into the wrong sensor since the temp. gauge unit is also a T arrangement is simple but in the end you can still use the SAFC you just might not need it for awhile. Look at that first, the sensor sticks up and has a oval end in the plastic and the harness plug used to be a molded rubber boot. If a hard plastic connector is on there and you see that other on the temp. gauge unit that sticks out sideways just switch them back. I'd save that dyno time till later.

[jolyrgr]

I only purchased the SAFC because the tuner said this would be the most affective and cheapest way to solve the running rich issue without having to replace a bunch of parts and trial and error and spend a lot of money.

 

If it were me, I would find another tuner. That type of lazy advise will not fair you well with these cars. Buying a system to make adjustments to a failing part, is only going to at best postpone the inevitable, and at worst grenade your motor.

 

Best thing you can get first, is a copy of the factory service manuals. That will eliminate a lot of the "having to replace a bunch of parts and trial and error and spend a lot of money" the tuner referenced, and you can be assured that you have a working system to start from.

 

JR

[87Mitsu]

The tuners are actually really good before hooking up the SAFC they gave it one pull on the dyno to see what the AFR was and it was so rich they suggested that it not be run anymore. They then went to figure why the car may be running rich, so the first thing they checked was the original intercooler pipes and it turns out that was the problem the car has a boost leak so I had the SAFC installed anyway for the future. But for now I will need to get hard pipes.

[Indiana]

On of our cars ( http://www.b2600turbo.com/kurt88.htm ) motor, stock cam, stock ignition system, stock pump, stock fuel system and stock pipes through the radiator support and a stock intercooler and not even a fan blowing on the intercooler made 261hp. HARD PIPEs aren't the magic wonderful thing they are made out to be either. Air flow through a larger pipe will be slower given the same pressure source, your turbo, and lag is filling all that up. You end up gaining nothing and going backwards. The stock intercooler will get heat soaked in town and is only good for little pulls but it will work at higher speeds. Its not all that efficient either. If you decide to go ahead and get hardpipes then get them with a better intercooler don't buy them to fit a stock POS intercooler. If you don't unplug the exhaust its not helping much to try and shove more into it. If you don't want a header then greatly port out your stock exhaust manifold. If you want to spend some money and it seems you want to, if you haven't had the exhaust enlarged then you might consider now a slightly larger turbo and a secondary injector in place of your primary since you did get your translator installed. Being too rich you still need to look for. You'll need some gauges such as a boost gauge as that factory one isn't any good and if you like a wideband 02 sensor. AEM is now making this new thing that sends 02 and EGTs from it to your cell phone or laptop. You do not have to buy those gauges and install them now.

 

its called X-WiFi

http://www.aemelectronics.com/x-wifi-35/

[87Mitsu]

Thank you Indiana yes I do plan on upgrading the exhaust,a full 3in system and I plan on getting a boost gauge and a AEM wideband gauge. The only thing I am not sure about is the injector and intercooler sizing.What size injectors and inter cooler should I run? I am only looking to take this car to 350hp and I also plan on running a Bosch 350 fuel pump inline to the stock one.