High Compression Stroker

[Locutus78]

I am foreseeing problems with my starter on my new motor. I just had a stroker with 10:1 custom pistons put in my 97 GST, and when we were getting it to start for the first time last night the starter kept binding. Even once we got it up and running if it does not turn over right away the starter binds. My mechanic said that with those pistons this will be a regular occurance. The question is does someone make a "heavy duty" starter for a 2g FWD, or will a N/A or another car maker's starter fit?

 

[95blackGsTurbo]

No and why in gods name would you run 10.5:1 compression? Good luck running over 10psi on the any turbo before knocking like crazy. You can't run that much compression on a turbo motor and expect to make any power short of using straight alcohol as a fuel. Hope you have a hell of a headgasket and all ARP hardware for that.

 

[whitehot 93]

I think 10.5 compression may not be a bad idea. It will be great for spool, with a lot of low end torque. The Buick guys do it all the time, and run 30psi of boost. Sorry to stray from the issue. Is your car a manual or automatic? Maybe you don't have the correct spacers? I don't see why your selection of pistons could cause a starter to bind. It sounds to me that there is an issue between the flexplate to starter. I am unaware of any heavy duty starter.

 

[Locutus78]

No .

Thank you for your answer

 

[95blackGsTurbo]

I think 10.5 compression may not be a bad idea. It will be great for spool, with a lot of low end torque.

It is a VERY bad idea. Search and you will find how bad of an idea it is. As for the Buick guys...have you ever felt a GN rod compared to a DSM rod...BIG difference in build and wieght.
http://dsmtuners.com/forums/showthread.php?t=180148&highlight=high+compression

 

[GVR4592]

I don't think it's such a bad idea to run high compression, Magnus Motorsports has been doing it for years.

As for the starter issue, I don't know if your compression is too high to cause the starter to bind. I've seen it happen on SBC's, but never on an import. My buddy has a 13.5:1 Honda engine and his starter engages just like stock. I would verify that the starter is getting the correct voltage and make sure it's grounded properly. Also check the wires for any corrosion. Are all of the starter bolts tight?

 

[95blackGsTurbo]

Yeah but that's not on a DD.

 

[GVR4592]

Yeah but that's not on a DD.

It doesn't matter, it's all in the tuning. Have you ever tuned a high compression turbocharged engine?

 

[Locutus78]

I think 10.5 compression may not be a bad idea. It will be great for spool, with a lot of low end torque. The Buick guys do it all the time, and run 30psi of boost. Sorry to stray from the issue. Is your car a manual or automatic? Maybe you don't have the correct spacers? I don't see why your selection of pistons could cause a starter to bind. It sounds to me that there is an issue between the flexplate to starter. I am unaware of any heavy duty starter.

Thank you, this is what I was looking for, as far as help. I will check those things.

As for the starter issue, I don't know if your compression is too high to cause the starter to bind. I've seen it happen on SBC's, but never on an import. My buddy has a 13.5:1 Honda engine and his starter engages just like stock. I would verify that the starter is getting the correct voltage and make sure it's grounded properly. Also check the wires for any corrosion. Are all of the starter bolts tight?

I know we had to sand a spot on the firewall for the starter to get a ground. Will also look for electrical. I know we tightened the bolts down real good. It will really only do it if it has to try and turn a few times before turning over. It was the first time(s) it has been started in a while, and may wind up being one of "kinks" that have to be worked out. Just trying to foresee and solve problems.

If you look in my profile you can see my setup (cooling, fuel, etc)

 

[carsaval]

I have a friend with one of the rare turbo storms. He had some redneck rebuilt his motor and the guy put in 11/1 pistons. well a couple hundreds miles later and his turbo was no more. He covered it with a plate. let me just say my friend is like einstien, in that he needs to comb his hair. but non the less I believe that if you have the fuel the air and the tunning ability, not to metion cooling ability. I would say why dont you experiment and let us know what happens.

 

[GVR4592]

Thank you, this is what I was looking for, as far as help. I will check those things.



I know we had to sand a spot on the firewall for the starter to get a ground. Will also look for electrical. I know we tightened the bolts down real good. It will really only do it if it has to try and turn a few times before turning over. It was the first time(s) it has been started in a while, and may wind up being one of "kinks" that have to be worked out. Just trying to foresee and solve problems.

If you look in my profile you can see my setup (cooling, fuel, etc)

I would move the ground to the stock location and see if it helps. Is base ignition timing adjustable on 97's? If it is that might be part of your problem.

 

[Locutus78]

I have a friend with one of the rare turbo storms. He had some redneck rebuilt his motor and the guy put in 11/1 pistons. well a couple hundreds miles later and his turbo was no more. He covered it with a plate. let me just say my friend is like einstien, in that he needs to comb his hair. but non the less I believe that if you have the fuel the air and the tunning ability, not to metion cooling ability. I would say why dont you experiment and let us know what happens.

A little history on the motor: It was built by FP for a road race car. The guy ran 3 races approx 500 miles (after it was broke in by FP). He kept chewing up 3rd and 4th on his tranny, and he went to a tube frame. I have a better transmission and won't be road racing it. Not to mention the incredible deal I got on it. Everything including the turbo, was built and ported by FP, so I am confident in the engine and turbo.

 

[95blackGsTurbo]

It doesn't matter, it's all in the tuning. Have you ever tuned a high compression turbocharged engine?

Yeah it was actually pretty easy but it was a 377 11:1.

 

[GVR4592]

So what's the problem then?

 

[95blackGsTurbo]

The rods. Magnus runs there rods...FP kit comes with Eagle rods. Small and lightwieght. You would think that the little aluminum rod would bend very easily under that much CC pressure. And if it's a daily driver the octane level would pose a problem...although meth. injection could fix that....If FP built it though it should be fine just the streetability issue.

 

[GVR4592]

Who said anything about aluminum rods? Even if they were aluminum rods they aren't going to bed under that cylinder pressure.

 

[awdtalontsi1992]

I get the feeling 95blackGsTurbo thought Eagles were aluminum. This would be an incorrect assumption. The higher you can raise you compression.....to a point....without having to lower the boost the better. The shop I worked at helped in the development of a ford 302 turbo motor. We found that by raising the compression and lowering the boost we could make more power. There was also a big increase in the low/mid power, increased spool, and much flatter torque curve overall. Because the motor was from a road race car they probably raised the compression and lowered the boost so they could get a better powerband. For a street car this would be a good idea. The threshold for detonation will very tricky and good tuning is a must. Howver the trade off on a street car will be worth it in my opinion. Keep us informed on your progress.

As for the starter issue. It is very unlikely that the problem is a result of the higher compression. I would look into making sure the alignment of the starter and ring gear is correct.

 

[andymoraitis]

I've always said that my dream motor would be around 10.5-11:1 2.4 with low timing and methanol injection. That thing would be a screamer with a great pump gas turbo like a 60-1 at 25 psi. The thought of it makes me shiver.

 

[Locutus78]

The rods. Magnus runs there rods...FP kit comes with Eagle rods. Small and lightwieght. You would think that the little aluminum rod would bend very easily under that much CC pressure. And if it's a daily driver the octane level would pose a problem...although meth. injection could fix that....If FP built it though it should be fine just the streetability issue.

These light weight, forged steel connecting rods are a great upgrade for the 4G63. They are strong enough to handle 600+hp, but are quite a bit less expensive than many of their competitors. Available for both 6-bolt and 7-bolt applications.

It will be my DD torque monster on a "conservitave" tune, with the C16 tune for those special occasions.

 

[Black Majik]

Binding isn't really the correct term, it's engaging correctly, turns the motor correctly. What he's talking about is it just doesn't have enough "umph"(read strength) to do it more than a couple of turns with out struggling. This motor was hard to turn over by hand when it was building compression, then turned over smooth as glass on the down stroke or with the plugs out. I think the starter will be fine, but may wear out quicker than usual due to this.

 

[nightspeed87]

A little history on the motor: It was built by FP for a road race car. The guy ran 3 races approx 500 miles (after it was broke in by FP). He kept chewing up 3rd and 4th on his tranny, and he went to a tube frame. I have a better transmission and won't be road racing it. Not to mention the incredible deal I got on it. Everything including the turbo, was built and ported by FP, so I am confident in the engine and turbo.

Thats going to be some motor when its tuned right. ( You do have a chip/ or link right?)
Wont be all out drag material, but for a full street set up it sounds good, stroker and high compression- the combination of the two will give you hella torque and low end/ mid range power, and with proper tuning/ fuel/ ignition timing you should still be able to squeeze perhaps 20 somethin psi out of it with a large turbo, and ( in my opinion not because of the compression) but because of the stroker it will spool fast.
I believe Ive heard that strokers require less ign advance anyway so you probably will be ok with the higher compression as long as you keep adv low and boost high as possible it will still make a lot of power.
Keep in mind you are a gst, your going to be melting your tires when you gun it
I hope you have a lsd for that

 

[whitehot 93]

Even if they were aluminum rods, which they are not..... They would be plenty strong to handle the horsepower. Top Fuel Engines use Aluminum rods and make more horsepower per cylinder than you do in the entire engine.

The rods. Magnus runs there rods...FP kit comes with Eagle rods. Small and lightwieght. You would think that the little aluminum rod would bend very easily under that much CC pressure. And if it's a daily driver the octane level would pose a problem...although meth. injection could fix that....If FP built it though it should be fine just the streetability issue.

 

[JayRolla]

Doesnt having real high compression make it hard for the stock starter to get her going. I know the big v8 guys when they get lots of compression they need a larger starter just to get it going. I know the compression would cause it to bind.

 

[Locutus78]

Doesnt having real high compression make it hard for the stock starter to get her going. I know the big v8 guys when they get lots of compression they need a larger starter just to get it going. I know the compression would cause it to bind.

That was the reason I started this thread to get some feedback. A lot of helpful responses. Black Majik is one of the mechanics that is working on the car at F.I.S.T. racing here in Houston. Like he said it might just wear out sooner than normal, thus why I asked about a heavy duty started or if a higher compression N/A engine starter would mount up.

Thats going to be some motor when its tuned right. ( You do have a chip/ or link right?)
Wont be all out drag material, but for a full street set up it sounds good, stroker and high compression- the combination of the two will give you hella torque and low end/ mid range power, and with proper tuning/ fuel/ ignition timing you should still be able to squeeze perhaps 20 somethin psi out of it with a large turbo, and ( in my opinion not because of the compression) but because of the stroker it will spool fast.
I believe Ive heard that strokers require less ign advance anyway so you probably will be ok with the higher compression as long as you keep adv low and boost high as possible it will still make a lot of power.
Keep in mind you are a gst, your going to be melting your tires when you gun it
I hope you have a lsd for that

My setup is in my profile, but yes I am using Link, yes I have a stage 2 tranny with Quaife LSD. I am not cutting any corners with this car, because I know that even if done right you sometimes have to do it twice.

 

[nightspeed87]

call mitsubishi and see if they even carry higher power starters if you think it would help.
I can see it making sense as of why you say it would be harder to start since the compression stroke would have more resistance, but I dont know to what point would make a difference. I mean yea 10.1 is high, but i wouldnt think the starter would have problems unless you had like 20.1 compression or somethin stupid like that .
I suppose it should be ok though if you have honda guys running around with 13. somethin compression, I mean once a spark hits some fuel its going to handle the rest, so the only way the starter should wear out sooner is if youd have to hold the ignition key in the start position for like 3 or 4 seconds before it catches.