installed HIGH compression pistons OMG

[1SloColt]

This thread is great. My boss is sitting here laughing his ass of at some of you people. Then again some of you like DSMJim and a few select others are actually making sense. For those of you that think you can't run high boost on high compression tell that to my boss and his 71 Chevelle Big Block with 13.7:1 compression and 13 psi on a 871-1 supercharged. (FYI Thats a top fuel supercharger). He owns his own motor building place. We custom grind cams and lightwieght cranks and whatnot here. Running that kinda compression and boost combo wouldn't be impossible but it depends no what kind of rods you have. I have a friend with a 800+ hp DSM running an RS65 turbo but his motor has forged crank, titanium rods and titanium valvetrain parts. It can be done but at a price to support what you are going to try and do. Some of you are so far out in left field it's not even funny. I personally think that if he keeps his knock down he should be alright. I don't think it will be a very reliable daily driver and you better find about the most expensive headgasket you can find and get ARP EVERYTHING. I personally think this thread should just be closed before some people out there that halfway know what they are talking about get confused and start infecting other people.

Your friend can't be making 800hp on a 4g63 or even a stroker motor because the RS65 can't flow enough to make that much power on that motor. Also, why do you need ARP everything? People have been running +25psi on stock HG and headstuds for a long time.

 

[ACKERSON]

What pistons are you running? You said they were cast mitsu pistons. I really dont think the compression is quite as high as you think it is. I'm not aware of any factory mitsu turbo piston that has more than 8.8:1 compresson. Can you give us a complete list of what is in your bottom end and which cylinder head you are using? I read the mods in your profile but I dont know if that is up to date.

 

[armandovivoni]

yes the list is from my old 7 bolt 4g63.

this now is a 6 bolt. with stock rods. balance shafts eliminated and fully rebuilt. arp head studs and cometics hp head gasket seal the head with the block at 110LB torque. the head is the same I used on the 7 bolt. its a 1g head with hks 272/272, crower springs and retainers. and the rest of the head is stock. I dont remember exactly but I think pistons said on top 63DM. I have plenty of fuel 1,152cc inj. and the complete fuel system upgraded. I now use a T4/T3 turbo .70 57trim/ .48 stage 3, I have a front mount IC 32x12x3, with 2 1/2" piping from turbo to IC and 3" piping to the intake manifold. I have a turbo xs rfl BOV, a 70mm throttle, sheetmetal intake manifold. Ill put pics.

this pic you can see the IC. bumper is all broken, some dumb guy crashed with my car right there were its sitting and left.

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for some reason I cannot put more images. but check them yourself at www.cardomain.com/id/armandovivoni LINK

pics are in order from new(top) to old(bottom)

 

[Coup D E'Tat]

The RS65 cannot support "800+" HP (whatever "800+" means.) 65 lbs/min of airflow, by itself, cannot support that power.

And running high compression and high boost is fine, if you know what you're doing. I'm interested to see how it goes, so make sure to post the results.

Later,

 

[95blackGsTurbo]

Then I guess the dyno was wrong. With his setup and spray I don't doubt that he got 800 out of it. So your telling me for Shep to have 1000hp he has to be pushing 100lbs a minute. I don't think they ever make a turbo that big so he can be doing it by your theory. A 60-1 can't put down 682.2 either I guess but it did that too on his old setup. I won't even tell you what he will be runnin for PSI cause all I will get it. YOU CAN'T DO THAT. IT WON'T WORK...YADAYADAYADA. If the guys at AGP and one's who sold him his motor parts say it will hold 35psi then I'm sure it will. I just wanna see him run it after its tuned.

 

[Coup D E'Tat]

Then I guess the dyno was wrong. With his setup and spray I don't doubt that he got 800 out of it. So your telling me for Shep to have 1000hp he has to be pushing 100lbs a minute. I don't think they ever make a turbo that big so he can be doing it by your theory. A 60-1 can't put down 682.2 either I guess but it did that too on his old setup. I won't even tell you what he will be runnin for PSI cause all I will get it. YOU CAN'T DO THAT. IT WON'T WORK...YADAYADAYADA. If the guys at AGP and one's who sold him his motor parts say it will hold 35psi then I'm sure it will. I just wanna see him run it after its tuned.

Well, first and foremost,

65 lbs/min of airflow, by itself, cannot support that power.

Then, you say

With his setup and spray I don't doubt that he got 800 out of it.

Does this mean you really have no idea what he made, only what you've heard?

What is the guy's name? I'm sure if he really has "800+" horsepower, someone will know of him, or I'll be able to find something to back up your statements.

Also, please do some research before you throw things around like "I don't think they even make turbos that big" because the market DOES include turbos that will flow 100+ lbs/min. Shep is running a GT42, right? Those flow around 80lbs/min, don't they?

 

[GPTourer]

If this is true then explain what happens when you super mega unobtainium rods hold up, but you aluminum pistons melt from detonation.

He said "unobtanium" .

 

[armandovivoni]

hmmm weird. yesturday I found what I thought was the problem, and today all morning car was working fine. then later in the afternoon stupid problem starts again and this time worse. now it does it even before the car starts to pull. 1rst gear. I step on it and suddenly engine looses all power. I let go of the gas, step on it again quikly and its all good, but change to second gear and it does it again. could a bad camsensor be the problem?

 

[ADrewzki]

No. If you had a bad sensor, the problem would persist. You state that your problem goes away when you release and then step on the pedal. So I would say no.

 

[armandovivoni]

so then its in the wiring?

in neutral it doesnt do it.

 

[95AWD_TSI_TALON]

I am running 7.5:1 cr motor on a T66@32psi 93 octane..... and yes race gas is another world from pump. But I have sat here and read throught this entire thread and its amazing what some absorb into there heads. There is a honda shop over in Calf. that is building B-series 12:1cr with 24psi (keep in mine psi means NOTHING especialy when comparing different cars! turbo size-10psi on my turbo would flow like 20psi on a 16g ) airflow lbs /cr is what you want to compare. Now I remember them talking about having to tune that car in 2psi intervals!!!! That is how corky they are. It can be done. But what surprised me is that mirage got tuned then you guys raced....I would be leary of any shop tuning my car and sending me out the door running 14psi

Also on the ARP head studs torqued to 110 and not blowing the head off still. Extremmotor sports (yes glazer) put a "JDM 6 bolt"in one of my NOW customers cars, on big16g@16psi lifted the head and blew apart the Mitsu. 3 layer. They put a NA motor in, I took it out and the pistons were DOMED. Almost as bad as the 12.5:1 cr in my brothers b18c1 I built (NA so no first hand experience on that ....yet)

None the less first hand mistakes make you realize them most. But the money lost make you realize far more....you would still have a good block,head, oil pan,oil pump, and as long as you dont have my bad luck a good radiator and good turbo. I blew my stock motor up: bent valves, chunk of rod went throught front of case and cracked radiator and turbo seized due to pushing 21psi @ 8kRPM and the motor shuting off.
Matthew

 

[GPTourer]

I am running 7.5:1 cr motor on a T66@32psi 93 octane.....

Got any pictures of your engine?

 

[THE_ARTIST_]

is that an arospeed intake manifold?

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[armandovivoni]

I am running 7.5:1 cr motor on a T66@32psi 93 octane

32 psi on pump gas!! what do you use to tune your engine? do you have water injection? or are you just pulling hard on timing?

 

[SilverJester]

No. If you had a bad sensor, the problem would persist. You state that your problem goes away when you release and then step on the pedal. So I would say no.

Actually it could be. I just had a crank sensor go bad on me. At first I thought it was a bad connection as well, it seemed to magically go away for about a month and then all of a sudden it was back. And the car would stutter for only a second, and very randomly some days it wouldn't do it at all some times may 5 times a day. Then one day I was letting my car warm up, it idled for a about 5 mins then shut off. I turned it back on it idled for another 2 mins, die again, and after that wouldn't turn back on until I changed the crank sensor.

Electronics do weird and random things when they start to go bad, you could try checking you cam and crank sensors. Oh yeah, does your tach jump when it dies like that? mine would instantly go from 4k to 1k or sometimes from 2.5k to 6k although the engine obviously wasn't spinning that fast.

so then its in the wiring?

in neutral it doesnt do it.

Not necessarily (I mean it might be the wiring) but until the one day where it completly stoped working, I never had any problems at idle either. I had the same reasoning as you, road vibration must be shaking the connection loose.

 

[armandovivoni]

yes the tach does that jumping thing. but that doesn't tell me anything. it can jump cause the camtriger is going bad or cause a bad connection.

 

[95AWD_TSI_TALON]

32 psi on pump gas!! what do you use to tune your engine? do you have water injection? or are you just pulling hard on timing?

I am running dsmlink and no water injection is in the car just not hooked up right now. And I am running advanced timing right now about 18-20 degress at WOT. Tuned out to 10.5:1 AFR. But race gas in the car is another entire story . I daily drive the car .

 

[armandovivoni]

your timing is 18-20 degrees on top(added) to the base timming? how much is your base timming at?

I havent taken mine to the dyno yet. but my base timing is at 10 degrees and my timming advance from 4k rpm up is 25 degrees. thats added to the base. so it = 10+25 = 35 degrees at WOT

 

[95AWD_TSI_TALON]

your timing is 18-20 degrees on top(added) to the base timming? how much is your base timming at?

I havent taken mine to the dyno yet. but my base timing is at 10 degrees and my timming advance from 4k rpm up is 25 degrees. thats added to the base. so it = 10+25 = 35 degrees at WOT

No my base is 12 degree's also. I having added 4-8 degrees across the the rpm range. so TOTAL timing at wot is going up as high as 20 degrees!
matt

 

[bkblazen2003]

get a data logger and check your knock count. if you are getting enough knock the ecu can be pulling back timing.

high ompression turbo is great. but you mistake is taking all the ime to swap pistons and cheap out with un forged pistons. Highcompression turbo is great on the street but to have a long term set up you need forged highcompression pistons. You don't need to worry aout the block. They are iron and not aluminum like hondas.

You don't need all that boost to have a fast car with high compression. try to keep boost lower and tune with fuel and timing to further increase power. 5 psi should be all you need for 350-400 with the right parts.

 

[armandovivoni]

dude, if I could get 350hp at 5 psi I would be super happy. though I dont think its possible. maybe at 10-15 psi it could be close. yesturday a friend met a guy who has same pistons I do. he is runing at 16psi, with 550cc inj,apex afc, t3/t4 turbo, walbro255, and stock 2g head. he has a fwd just like me and he did 12.9 1/4 mile. this gave me lots of hope. and I think I could do better since I have much more go fast mods and better tuning management.

 

[GVR4592]

From the sounds of it your "high compression pistons" are probably 2nd gen or evo pistons.

95AWD_TSI_TALON I'm not calling you a liar but it's very very hard to believe you are running 20 degrees of total timing and 33 psi from a t66 on pump gas. If you are you should have a new record for the most power made on pump gas and if thats the case congratulations. How do are you able to get so much timing without knock on pumpgas?
I think Dre made his 504whp run at 30 psi on his agp 50 trim with 5 degrees of total timing on 93 octane. 20 degrees of timing at 33 psi on a t3/t66 with 93 octane is just a little to hard to swallow. Can you post a log file from dsmlink?

 

[armandovivoni]

bro, I have a second generation eclipse. I know what pistons I used to have.

 

[GVR4592]

I think that you don't have any idea what pistons are in your engine right now. So there is no way you can even estimate your compression ratio. It's a cast factory mitsu piston and you claim it's not a second gen piston, so it's probably an evo piston or an n/t piston. Why would you install a piston that you know nothing about?

 

[JiveMasterT]

I think that you don't have any idea what pistons are in your engine right now. So there is no way you can even estimate your compression ratio. It's a cast factory mitsu piston and you claim it's not a second gen piston, so it's probably an evo piston or an n/t piston. Why would you install a piston that you know nothing about?

good point... seriously... how high can it possibly be?