Hey guys, just want to get your opinion on something that happened today. Im gonna find out tomorrow, but the more opinions I get the more I can look for stuff that maybe I didnt think of.

So today I was heading to the shop and I was doing a long hard pull at 17psi in 4th. Right around 5k I felt a little jolt and at the same time I looked in the rear veiw mirror and seen a tiny puff of smoke. I let off the throttle and actually lost power for a few seconds. I regained power and limped it to the shop.

I did a comp test and I had nothing on cyl 1. I know alot of you are thinkn I threw a rod or piston, but I really dont think I did. Besides the car sounding like its missing, it idles fine. Theres no smoke coming out of the ass end, theres no "bad" noises coming from the motor. The oil looks fine aswell as the coolant.

I pulled all of the plugs out to check timing and that was dead on. Also while I was hand turning the motor, I did take notice that I can spin it with no probs what so ever and again no odd noises.

Im thinkn maybe a blown headgasket or something going on with the valves (which were just installed a month ago).

My whole bottom end is forged with 10.5:1. Ive been running 15+psi for over 3 years now. My AFR maps are near perfect, was at about 11.8 at the time of boost. I just put on a ported head with SS valves and Crane springs and retainers. Im using ARP studs with a Mitsu MLS.

Well I dont think I left anything out, lol.

What say you guys

TIA
DJ

man 10.5 with 15 psi, what kind of ignition settings are you running?

Even more important, what are the cam specs? Dynamic compression determines detonation... not static compression. So the 10.5 is only part of the equation.

Welp, the results are in...

I melted the #1 piston.

Like I previously said, Ive been running this setup for a long time now with no probs. Cams were stock along with stock ignition.

Anyways, Ive been having an overheating prob for about the last week. Besides a stuck stat, I was still losing coolant somewhere and I think from what the HG looked like, it might have been going into that cylinder.

So if coolant was geting into that cylinder, then the coolant couldve been working like a blowtorch on that piston and overheated it.

Now is the decision if I wanna just hang it up and get rid of the car and finish my S13/RB project or actually spend the time and money and rebuild. Blaaaah, lol

Thanks guys
DJ

So it just needs a 420a dropped in it? :D

Actually I have a block, all I really need to get are pistons and might aswell get new bearings. Im assuming the rod/rods are still good, lol.

Ouch!

I think it sounds like you know what you're doing over there, so I'd suggest rebuilding it. The car looks great in the flat black, so consider dropping CR a bit - say stock-ish - and just enjoy having a relatively easy-to-tune daily driver with big balls and focus your attention on the s13.

Why scrap out when you've got a good thing going, right? :thumbsup

how did 15+ psi + 10.5 CR feel?

Originally posted by talon749
how did 15+ psi + 10.5 CR feel?

Starting off, its really nice having that extra torque before boost, then when the turbo kicks in, if I have it at atleast half throttle, hold on. Thats of course if I get traction, lol, I could never run full boost in 1st or 2nd. Remember I was first running an SC61 and this TO4E, so with the high compression I was starting to boost at about 3k to 3500 depending on throttle location and then had full boost by 3500-3800. The high compression and larger turbo I think is a nice setup, because with the larger turbo it wouldnt boost if I didnt want it too, but I still had the torque to get going....does that make since, its kinda hard explain? lol

I could go from a 50 mph roll in 4th and drop it down to 3rd and just smoke the tires if I wanted to, but that didnt happen too much cuz I dont like buying tires out of stupidity, lol.

Ive never had a diff setup so I dont know how others are, but I didnt have problems beating even modified V8's with my setup. I have a buddy with a pretty nice Evo and he's always trying to beat me with no luck, lol.

All in all it was an awesome ride, except for that damn annoying JE piston slap...soundn like a damn diesel all the time, lol. I really dont want to see it gone, this is the longest car Ive ever owned and I like having a car that everyone thinks is slow until they mess with me, lol.

Ive decided Im going to do exactly what you suggested DR1665 and thats finishing the S13 and in the meantime start to get parts and finally rebuild. I cant decide though what comp I want to do. What I had is telling me to stick with 10.5 and start getting back into to the ignition part of my MegaSquirt, but then I also think to play it safe and go with a lower comp, prolly no lower than stock.

Oh well, only time will tell, lol

Thanks guys
DJ

that sounds pretty amazing haha, 3rd gear burn out at 50mph is really impressive, i bet even with the 9.6:1 CR at the 15psi you will be making lots a power, even more reliable too, I wonder how much those custom pistons will cost.

Originally posted by talon749
that sounds pretty amazing haha, 3rd gear burn out at 50mph is really impressive, i bet even with the 9.6:1 CR at the 15psi you will be making lots a power, even more reliable too, I wonder how much those custom pistons will cost.

Its funny you ask that, cuz the last hour Ive been looking for something close to the stock comp with no luck. Maybe they are a made order setup. If thats the case then maybe I will go with the regular 8.8 if not the 10.5. I dont want be spending some big bucks on just pistons. One way I can look at the 8.8, is I can turn to boost up even more, lol.

I'll keep lookin though

Can't wait to see what you plan now to go with DJ, seemed like it was a beast from what you were describing. Sucks about your luck, but now you can change it up a bit if you want. Good luck :thumbsup

MAN 10.5 COMPRESSION THATS WHAT I HAVE BEEN RUNNING AND EVERYONE SAYS THATS TO HIGH FOR BOOST I ORIGINALLY HAD HIGH COMPRESSION FOR NITROUS BUT GOT TO EXPENSIVE TO FILL IT TWICE ON SAT NIGHTS. WHAT KINDA SETUPS ARE YOU RUNNING. FUEL AND IGNITION.

Originally posted by SBR420A
MAN 10.5 COMPRESSION THATS WHAT I HAVE BEEN RUNNING AND EVERYONE SAYS THATS TO HIGH FOR BOOST I ORIGINALLY HAD HIGH COMPRESSION FOR NITROUS BUT GOT TO EXPENSIVE TO FILL IT TWICE ON SAT NIGHTS. WHAT KINDA SETUPS ARE YOU RUNNING. FUEL AND IGNITION.

Please stop using all CAPS. This is the 2nd thread I saw you do that in.

I believe he is using Megasquirt to control his fuel.

Originally posted by totaleclipse_05

Originally posted by SBR420A MAN 10.5 COMPRESSION THATS WHAT I HAVE BEEN RUNNING AND EVERYONE SAYS THATS TO HIGH FOR BOOST I ORIGINALLY HAD HIGH COMPRESSION FOR NITROUS BUT GOT TO EXPENSIVE TO FILL IT TWICE ON SAT NIGHTS. WHAT KINDA SETUPS ARE YOU RUNNING. FUEL AND IGNITION.

Please stop using all CAPS. This is the 2nd thread I saw you do that in. I believe he is using Megasquirt to control his fuel.

:scratch :bowdown :shrug Thats a badass setup. Wouldn't your car run better with 8:8:1 than 10:5:1. What pistons are you using JE ,eagle crower,mahle..

I'm turbo mine right the first time,gonna the the kit and parts needed a lill at a time, and forged internals. I'm ,wait til my stoker goes and then thats when I'll start. I'm not no, rush to turbo mine just yet. I've heard the advice along time in a forum.

That dude, is right whatever his name was I forget.

Originally posted by totaleclipse_05

Originally posted by SBR420A MAN 10.5 COMPRESSION THATS WHAT I HAVE BEEN RUNNING AND EVERYONE SAYS THATS TO HIGH FOR BOOST I ORIGINALLY HAD HIGH COMPRESSION FOR NITROUS BUT GOT TO EXPENSIVE TO FILL IT TWICE ON SAT NIGHTS. WHAT KINDA SETUPS ARE YOU RUNNING. FUEL AND IGNITION.

Please stop using all CAPS. This is the 2nd thread I saw you do that in. I believe he is using Megasquirt to control his fuel.

I told him to stop shouting once already!

as far as the car dj it sounds like you've got things fairly well sorted. 10.5 on boost must have been nice for low end, I know some of the VeeDub guys have been boosting the r32 golf at factory comp of 11.3 and those things are just mean off the line and everywhere im between

I REALLY DONT HAVE A CHOOSE ABOUT USING ALL CAPS TRUST ME I KNOW WHAT IT STANDS FOR BUT I WORK AT A DEALERSHIP AND IT IS PERMENATLY ON FOR WRITING UP WORK ORDERS......SO PLEASE EXCUSE IT.

I'm at a dealer and I still have a no caps function

Do you have a SHIFT key? You could try holding that down, and you'll type in lower case letters :shrug

DJ420a,

For your piston needs, look up Venolia. I got mine through ERT back in the day, but I'm thinking you might be able to deal direct. Depending on how long they hold onto specs, they should still have the specs on my 10.5:1s. Since they specialize in custom pistons, I highly doubt they would have any problems reducing the dome a bit to drop CR to 10.0:1 or whatever. The metal composition is supposed to be first rate. I've been told their pistons will melt before they will crack.

Expansion is very tolerable too. When I had my bottom end put together, I told them I was going to turbocharge things so they set the rings a bit on the loose side. I *do* get a minimal amount of slap at idle until the engine warms up, but you really don't notice it with the lope of the idle. On a boosted application, I doubt you'd hear much, if any, slapping at all.

Google them and check them out. They're quality.

well the caps lock doesnt work but the shift does...... good job edxmon. so is 10.5-1 to high to run boost i am talk about jus 5 or 6 pounds

Originally posted by SBR420A
well the caps lock doesnt work but the shift does...... good job edxmon. so is 10.5-1 to high to run boost i am talk about jus 5 or 6 pounds

If you do, the only way I would do it is with atleast a wideband and an EGT.

The way I did it, was I just kept turning up the boost little by little as I datalogged and tuned. I actually had the car up to 20 psi, but when I got to about 4-5 grand, it would spit and sputter no matter how rich or lean I made it. Im sure it was the ignition not liking that, so I kept back it down till everything looked decent at 17 psi.

I do use the Megasquirt and I was just using fuel. Way back in the day I tried to use ignition, but something wasnt working right, so I just disconnected it. I still have all the ignition hardware under the hood and ready to go.

The bottom end setup was JE 10.5:1-20 over with Eagle rods.

Im have some buddies that run a few shops and stores around here and a few of them said they could hook me up with one JE piston. Im not sure how true that is right now, but maybe that would be the way to go and start learning the ignition part of the MS again. :shrug

DR1665, Im def going to look into these Venolia's you speak of aswell as getting ahold of ERT.

For now I have a boosted inline 6 to worry about, lol

yeah i have the whole sbr stage 2 block with stage 2 heads and all the gidgets and gadgets, i mean if you are pushing 17 pounds i should be able to get my 5 or 6 i want

Sorry to hear about your car. I was boosting 15psi with a super 16G and 10.5 compression pistons 2 years ago. I ordered a 8.6:1 block, but howell sent me a 10.5 block. I now have a 8.6:1 compression and i feel a difference. The 10.5 felt very nice and i always wondered why the car felt better back then and when i found out about having 10.5, i realized why it felt fast. I loved the 10.5 much better, but decided to take it safe since i have no ignition mods and i still have a sfmu for fuel system. I now have a SC6169, so i bought the 8.6:1 so i can boost 20psi when i get the portfueler system. Good luck with both projects.

Originally posted by freddy_00_69
Sorry to hear about your car. I was boosting 15psi with a super 16G and 10.5 compression pistons 2 years ago. I ordered a 8.6:1 block, but howell sent me a 10.5 block. I now have a 8.6:1 compression and i feel a difference. The 10.5 felt very nice and i always wondered why the car felt better back then and when i found out about having 10.5, i realized why it felt fast. I loved the 10.5 much better, but decided to take it safe since i have no ignition mods and i still have a sfmu for fuel system. I now have a SC6169, so i bought the 8.6:1 so i can boost 20psi when i get the portfueler system. Good luck with both projects.

I have the SC61 on the RB cuz I figure its gonna like the SC61 more than the TO4E, but Im actually thinkn about selling the TO4E and getting another SC61 so I will have 2. You gotta give up for Precision, thats just a badass turbo, lol.

Are you actually running your 8.6/SC61 setup now? If so, how much of a diff are you experiencing than when you had the high comp? I figure if I was running 15+ on the 10.5, then with a low comp setup, I might be able to run roughly 10 more.....who knows, lol.

Originally posted by DJ420a

Originally posted by freddy_00_69 Sorry to hear about your car. I was boosting 15psi with a super 16G and 10.5 compression pistons 2 years ago. I ordered a 8.6:1 block, but howell sent me a 10.5 block. I now have a 8.6:1 compression and i feel a difference. The 10.5 felt very nice and i always wondered why the car felt better back then and when i found out about having 10.5, i realized why it felt fast. I loved the 10.5 much better, but decided to take it safe since i have no ignition mods and i still have a sfmu for fuel system. I now have a SC6169, so i bought the 8.6:1 so i can boost 20psi when i get the portfueler system. Good luck with both projects.

I have the SC61 on the RB cuz I figure its gonna like the SC61 more than the TO4E, but Im actually thinkn about selling the TO4E and getting another SC61 so I will have 2. You gotta give up for Precision, thats just a badass turbo, lol. Are you actually running your 8.6/SC61 setup now? If so, how much of a diff are you experiencing than when you had the high comp? I figure if I was running 15+ on the 10.5, then with a low comp setup, I might be able to run roughly 10 more.....who knows, lol.

I ran the super 16g with the 10.5 unknowingly, and i got the SC61 after i put in the 8.6:1. I felt a difference in just normal driving, but the SC6169 pulls hard as hell now and i am only at 7psi, cant turn it up until i figure out what the hell is wrong with my 42lb injectors or wait until i get the portfueler. I like this turbo, i got it with the 4 inch inlet option.

i know this is going to sound stupid but how do you switch the com, you guys are talking about 10.5 the the stock com, which is better. it looks like you guys know a lot about your cars and i want to know a lot more too. i think that if i read and ask Q's i will learn a lot more so i can run my 420a to its full. i hope to soon run the hahn t20 turbo.

stock compression is like 9:0.1 or some where in that region not positive so dont qoute me if i am wrong. So to chage compression you must tear in to your motor etc higher pistons,rods,shave the head stuff like that.......anybody else feel free to input

Originally posted by SBR420A
stock compression is like 9:0.1 or some where in that region

Close.

General musings on compression ratio (CR) for the new guy.

-Stock 2GNT CR is 9.6:1
-For every point you increase CR, you increase bhp by 4%. (Ex: Going from 9.6:1 to 10.6:1CR would yield 5% more hp at the crank.)
-The higher the CR, the more mechanical energy the engine can get out of the air-fuel mixture. The downside is that compressing matter creates heat, so too much compression will get things hot enough to explode (spontaneous combustion), meaning detonation and engine destruction.

very well put

Originally posted by SBR420A
stock compression is like 9:0.1 or some where in that region not positive so dont qoute me if i am wrong. So to chage compression you must tear in to your motor etc higher pistons,rods,shave the head stuff like that.......anybody else feel free to input

Ehh make it easy... mill the head. Unless you're doing a full rebuild. But if working with a stock shortblock, mill the head to bump compression.

Ehh make it easy... mill the head. Unless you're doing a full rebuild. But if working with a stock shortblock, mill the head to bump compression.

Milling the head isn't the best way to increase compression. I would suggest only milling the head to make sure it seats properly on the block. Then I would suggest letting the machinist take what he feels best off the head. I think my head was milled about .015" to square it up after I popped a timing belt.

How else are you going to increase compression ON A STOCK SHORTBLOCK as I specified?

Milling a head down so you can go from 9.6:1 to 9.65:1 compression is pretty worthless. Sorry.

Why would you only mill it that little bit? That would be silly.

milling the head isnt the best way to raise compression as stated above. Milling the head to raise compression may leave the head useless in the future rebuilded because you can only mill so much off our head before it becomes a paper weight. When you spend 1500 in porting the mill off a significant amount, the next rebuild may require the head be milled to the point that the head integrety is compromised. Now you have 1500 in port work that is great for holding your door open.

If you want to raise compression just do it the right way with a set of pistons. Cheating only costs more money in the future.

DJ, dont hang it up. Rebuild it. Before you know it its only going to be a handful of the experienced 420a'ers left. The Icons of this site are slowly disappearing and we are going back to cold air intakes and nitrous for those who think they have a built car. The true built 2GNT is becomming a thing of the past. Before you know it, its going to be Dino, Thura, myself and a few others. Come on Dj.....stick with us. Lets keep 2gnt free of stupidity.

Thanks for explaining that better than I could. I appreciate it.

doing it the right way may look like a lot of money but if you are going certain routes the benefits will be well worth it in the end. jus take the process step by step and remember if you can to find another car to drive around for a while dont rush this.

Originally posted by Star Turbo Talon
DJ, dont hang it up. Rebuild it. Before you know it its only going to be a handful of the experienced 420a'ers left. The Icons of this site are slowly disappearing and we are going back to cold air intakes and nitrous for those who think they have a built car. The true built 2GNT is becomming a thing of the past. Before you know it, its going to be Dino, Thura, myself and a few others. Come on Dj.....stick with us. Lets keep 2gnt free of stupidity.

Well, everytime I drive to my shop since this has happened, the Eclipse has looked like your dog sitting at the edge of your yard all excited becuase your finally home, lol. Ive had the car way to long to just hang it up. This car has actually been the only car that hasnt given too many problems besides your normal 420a bugs and things that I have done to it. So Im def gonna rebuild. I paid my machinist a visit just yesterday to decide what direction we might take.

Really, to me, this going to be a fairly quick and simple rebuild. Its just deciding what comp to go with. Ive never had low comp, so Ive got this idea locked in my head that before boost, the car is gonna suck. Then with the turbo's I have, the motor is gonna be laggy as hell. Im sure this is all in my head.

Something keeps telling me to just get another 10.5 piston, since really thats all I need. Then again, lower comp equals safer motor and I also have a chance to get rid of that piston slap thats been a thorn in my side for 3 years.

Anywho, thanks for the pep talk Star Turbo Talon. Every word you said made absolute sense. I cant just hang up on the car that has taught me a hell of alot about motors, forced induction, suspension and most of all broadening my sense of imagination to make things work.

Thanks again
DJ

I can relate and agree with you leaning towards going back to higher compression. I was running JE 10.5's after my 2nd build and it was a major difference from the 8.8's when used with a 20g. On my 3rd build I decided to go with 9.25:1 CP pistons. These were a great happy medium and you may want to look up the standard offerings from them. Although I know mine had to be custom made when I got them through VT Engines, they may have more to offer now.



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Santiago
boosted 420a...(2.2l v8 eater)
02 WRX
95 T/A 383ci
03 Harley XL 92ci w/ NOS