G4cs tuning and information

[Sleepr awd]

I have come across a 92 gvr4 with a g4cs motor hybrid and a holset turbo with supporting mods. It does not run at all or well when it was but according to the owner it is because he has not tuned it right as of yet. He works too manyhours right now and wants out of the project because it is costing him too much in storage fees so I agreed to take it off his hands. Let's assume I'm stealing it from him as far as price goes. I do know this guy personally so I know he is being as straightforward as possible. And the last setup he had on it was simply beastly.

Is there a basic tune for this sort of motor setup I can get from someone on here?? Or will I have to go in and start from scratch. I assume he is using dsmlink however it is possible it is a standalone system.

I will update as time progresses and I appreciate any help anyone can give me I looked allover dsmtuners and there is no mention of tuning this setup

[david-b]

You HAVE to get on the dyno and tune. You can't just drag and drop a setup from another car. Every car (even with identical setups) are different. If the car doesn't start, I would have to think there may be something a little bigger than just tuning. Do a compression test before you buy. If you get a great price on it, hell go for it.

[Thor06]

Originally Posted by david-b

You can't just drag and drop a setup from another car. Every car (even with identical setups) are different.

There is truth to this, but if its not running simply because of a tune, if it has link and you can find someone with a similar setup, I think you can get their tune file and put it on your car. Obviously this wouldnt be permanent, but you could limp it home I think.

Do you have a mods list? If its just an SAFC its just matter of playing with sliders I think, but like I said, I think if its got DSMlink you can just get corrections for the injector size and 1g/2g and you should be able to drive it home as long as you dont boost. If its AEM EMS, Haltec, or Emanage, I dont know what to tell you.

[SilvrEclipse]

I doubt he is running a stand alone system. You only see that on extremely modified cars, which could be controlled by dsmlink so its really their choice.

I would find out what he is using to tune the car with. Find out the stock injector size and find out what are in there now.

[Sleepr awd]

o clear something up. This will not be a drag and drop setup. The whole car has been setup for this motor combination and for the price I'm getting it for I could take off only the suspension and swap it with mine and scrap the rest and still get a hell of a deal out of it. I really need a tune just to build the fine tuning off of much like using a keydiver setup and going back with an safc to correct everything. Also there is no dyno in these parts to take it to and the closest one I'm not sure even messes with dsms. Unfortunately I will be doing some street tuning until I can come across some series cash.

I do not have an exact mods list no. I am sure it is either dsmlink or aem for engine management. It is safe to assume the injectors are larger than 700, it has a coil on plug setup, very large fmic, holset hx35 or hx40 turbo 3" or better ic piping, cams, 4 bolt LSD rear, big brakes of unknown brand, and anything else necessary to run this setup.

Forgot the built trans too.

Part of my concern was. Is there any additional compensation for the motor size or is it solely based on the amount of air let in??

[Sleepr awd]

talked with him more indepth

4gcs hybrid
wiseco pistons scat rods
adjustable cam gears and spare 2.4 gears
272's with light headwork
dsmlink
racing seats
5 black motegi 7 spokers still 4 lugs
trans built with double 2-3 evo shift forks
differential work
slowboy/ competition clutch 2800lb??
holset turbo

Symptoms were that it ran but would die when warmed up
oil had some discoloration and appeared a little silverish when checked
unsure on compression testing but he did not remember it to be favorable
turbo might be messed up if there were metal shavings in the oil

At least that is all I got on the subject cuz that is all he could remember and it does still need to be tuned

[david-b]

Shavings in oil are usually normal from a rebuild. Usually the left over debris gets all over the place. Turbo more than likely will also be shot from that.

If compression was "not favorable", then there's a problem with the motor and a tear apart is almost inevitable. Something is causing the motor to lose compression and causing it not to run.

[gthompson97]

I'm confused. Is it a 4g63/g4cs hybrid, or which type of hybrid? IIRC, the g4cs is a brother block to the 4g63, with the exception of a taller deck (6mm or so). Some people put the g4cs crank in the 4g63 block with special rods/pistons and you have a true 2.4, not 2.3 like most stroker kits. That's the only g4cs "hybrid" that I know of.

[Thor06]

Well first off, the metal shavings are from the rebuild yes, but its mainly from the parts wearing together. The break in can be thought of as "an extension of the machining process."

Secondly, the "hybrid" he speaks of is the g4cs block (I think you mean 6 mm there Garrett , since the 4g63 stroke is 88mm and the 4g64/g4cs stroke is 100mm, the difference is 12 mm and since that would be 6mm up and 6mm down, the deck height only needs to be an extra 6mm taller) and the DOHC 4g63 head. This works because the 4g63, 4g64/g4cs use the same casting, but the 4g64 and 4gcs bocks are bored out an extra mm and the deck height is left an extra 6mm tall. This is the only way to get the 2.4, the 4g64/g4cs crank in the 4g63 block is the 2.3. The only other hybrid is the 2.1 which is a 4g63 crank in a g4cs block with special long rods.

EDIT: Oh yeah, the Dave is right, the metal shavings can and do claim turbos after a fresh rebuild. The shavings get caught in the turbo bearings allowing insufficient oiling and cause it to burn itself out. The fix for this is to break it in with a turbo you dont care about and/or with a inline 10 micron (?) filter in the turbo feed line.

[Sleepr awd]

Right it is the g4cs block crank etc with the dohc turbo head on top of it which makes it a 2.4 turbo motor without needing to bore it out

It would be great news if it was something simple like a coil going out or something but it is my experience that when it rains it pours and I'll prolly start in on it and end up needing a whole new car. Btw if someone outright wants it I can work on getting it to someone.

[gthompson97]

Yes, I did mean 6mm, 6" would make it a 5.9! Imagine lag times with that beast! .

[Sleepr awd]

So I was thinking about it. And...

Has anyone had problems with the ignition control module?? At least on gm vehicles an ignition control module can cause this particular problem with the car starting and running and then dying after the car is warm.
Or is there another sensor that can cause a similar issue?? I was thinking the problem could be more electrical than mechanical and could be a much simpler fix thanexpected.
Though I still don't have the car yet so there is not much I can physically check. But it is nice to make a list of things needed to do.

[SilvrEclipse]

You could check things like the coil pack, plug wires, and put new plugs in it and check for spark. That would eliminate the common ignition problems.

I can garentee that this is problem is something electrical. You could also check fuel pressure on the car. I would check the o2 sensors, crank postion sensor, cam position sensor, IAC. Anything you can check I would do it.

If you still cant figure the problem out you may want to try a different ECU.

[kjewer1]

You have to get funny with the cam gears on that motor IIRC. If the cams are out of time, it could cause it to run crappy and get low or high compression test values. Probably as good a place as any to start. I've never built one of those tall deck motors, so I've never paid much attention to exactly what has to be done to get the cams in time.

Other than that, there is nothing special about that setup that would keep me from getting a 95% tune on it in 15 minutes. I wouldn't worry about the tuning. The holset turbo is probably a dodge diesel sized unit, which is typical, so the stock airflow sensor is not going to fly. If it has a MAFt on it, that is also a likely place to have some setting screwed up causing it to run like shit.

[Sleepr awd]

The cam gears on it are adjustables but you can use those or the 2.4 's cam gears which it is coming with as well.

Maf should be a gm blow through but the old motor would have been set on that anyways