Let me first get this out -
RWD 3.1 Turbo (16G) '88 Camaro here. Cast Iron heads and all...
Now, I noticed the TGP uses some Mahle pistons. Being that I've got the iron heads, I can't use your guy's pistons, correct? or can I, with like 7.5:1 cr? Just unsure on that part - what is the difference between the RWD cast and FWD pistons? Both engines have the same stroke and bore, same rod length, yet the Al heads are 28cc (IIRC) and the Irons are 50cc. Where is the difference made up?
Now, what is the beef with the TRW's? I can get a full rebuild kit, with the Federal Mogul Hypereutectic pistons (I assume the are TRW - i believe they are all owned by the same company) for $311. Are they that.. ah.. crappy?
And what IS the stock boost on a TGP? I'm finding anything from 10 to 14psi...
I believe stock boost for a TGP is ~7psi IIRC...sorry I can't be of more help on the other questions. Got any pictures of your turbocharged Camaro? :wink:
yeah let's see some pics! I used to have a 91 bird with the 3.1 V6 I wish I had turboed.
rofl... come on guys... this isn't going to turn into a Check Out The Turbo Camaro thread ;) I DO appreciate it, though - check out my Turbo Chronicles and Turbo Update threads on Thirdgen.org, in the V6 forums...
How about that piston info? :D
Well the only difference I see is that the iron head uses flat tops and the aluminum are dished. These Mahle pistons are recomended for stock and somewhat mild turbo aplications(12psi) over any other Cast piston. They have a reinforeced ring cast inside of it. I wouldn't recomend Hype pistons...well yea they run cooler but they don't like to be "shaked"...if you know what I mean. Have you checked the priceing on iron head forged pistons? I've seen them...they have more "meat" on the top than the dished alum head pistons. Have you also considered a aluminum head swap...I've heard of people doing them..but it'll set you back if you don't have a parts motor....And I think they do them to UP the compresion on the stock iron head pistons...either way, I don't think you really need one anyway.
7.5 cr...well it will somewhat run...I think the Turbo TAs had that...Not too sure.. Yea...but you'll have vaigly any non-boost power...well not a prob if you don't care for off boost power.
And stock boost for a TGP is like 8.5 I think. Too little...and is upgreadable to only 12.5 max...turbo falls face flat on efficiancy. Well its a t25...with like .80 ar..and guesstimate of .60 on the hot side. Don't know what Turbo you have..so Im sure if its bigger...(CFM)...it could go up to 14 psi on tgp electronics....more on aftermaket electronics or a 3bar costom chip.
Ok, just got your guy's piston info (from Federal Mogul) - Your pistons seem to have about a 30cc dish, wheras the stock 3.1 has about a 12cc dish. With the 50cc iron heads, 30cc dish gives me like 6.9:1 cr... WAY too low!
Appreciate the help guys... running a 16g (flows about 520 cfm vs T25 405 cfm)
And technically, it's still a 2.8 in the Camaro. I'm building the 3.1 now :D
Fuel cut on a TGP happens at 9 or 9.5 lbs.
Funny thing about the fuel cut... On my modded chip it's set to 11.5 (IIRC) and cut at 14 (again IIRC) I can hold 15 or 16 psi, as long as it fluctuates. If you hold the pedal down it maxes @ ~17 and 1 or 2 seconds it puts yer face into the steering wheel. :lol: This hasn't been a problem until I got the stutter fixed. (New Accel 8.8's and AC plugs) Now it's quite annoying if you aren't paying attention when you are racing.
Haha... what kind of power outputs are you guy's getting from your turbo 3.1s? My camaro weighs in at 3150 with me in it (weighed on a real scale, lol)
about 2950 without me. I'd like to run 10-12psi on the 8.5:1 cr 3.1, iron heads, with the 16g. I'd also be running ported/polished heads/intake, 3" exhaust (all the way, no cat), and a 204/214 @ .050" cam. Any ideas what she'd run, or how much power she might make?
Quote from: DowardHaha... what kind of power outputs are you guy's getting from your turbo 3.1s? My camaro weighs in at 3150 with me in it (weighed on a real scale, lol)
about 2950 without me. I'd like to run 10-12psi on the 8.5:1 cr 3.1, iron heads, with the 16g. I'd also be running ported/polished heads/intake, 3" exhaust (all the way, no cat), and a 204/214 @ .050" cam. Any ideas what she'd run, or how much power she might make?
I ran a 14.6 @ 95 with only a K&N filter and Jeff M's TopGun chip. Also, keep in mind that I weighed my TGP with me in it with 1/4 tank of gas and it weighed around 3590 pounds. That's with me weighing in at about 200 lbs. So, my TGP weighs about 3390 lbs with 1/4 tank of gas. :shock: :)
so now that this guy is helped i have a question about pistons.....excatly what do we have in there as stock and what is the best upgrade or replacment pistons that you guys have tried part numbers would be helpful if ya have them :D
You can use the TGP piston. And your 7.5# is about right. :lol:
TGP and n/a pistons are the same with a -.257 dish @ 26cc?s. The difference in compression is the heads. Look here for the difference. Down about half way.
http://www.w-body.com/forum/viewtopic.php?t=7028&postdays=0&postorder=asc&start=30
Mahle makes a ?106 dished piston which could be the 12cc you were talking about although math wise it comes out 10.7 cc provided the width is the same.
The difference between the TRW and the Mahle 027260.
Mahle / TRW
Skirt below the wrist pin. Yes / no.
Steel band cast in skirt between and into pin bosses. yes / no
Huge pin bosses. Yes / no.
Oil return per side. 2?? / 1??.
Weight 494-496 g / ? felt lighter.
Appearance Stout / like for a toy.
Cost 98 / 120-130
Don?t know that the TRW pistons wouldn?t be fine. That?s the problem, just don?t know. I decided not to use them.
Stock boost about 6#, wastegate blows open at around 8#.
What do you get for your 311.00 kit?
Hope this helps.
Jud
Chevy 3.1-T Camaro/Firebird 90-92 - Master Kit
INCLUDES
Federal Mogul Moly Rings
Federal Mogul recessed head Pistons
Federal Mogul Rod Brgs
Federal Mogul Main Brgs
Clevite Cam Brgs
Melling Oil Pump
Melling Timing Components
Pioneer Frost Plugs
Fel Pro Gaskets
$311 (called for price without lifter/cam)
Turn my 3.1 stock crank .010/.010 and have it nitrided, then use this kit, with a Melling MTC-5 Cam Kit (204/214 @ .050 - .420/.443 lift) with a ported 16g blowing 10-12 psi.
I can get the kit without the pistons, that's not a problem... I might even be able to get them with the Mahle pistons. Difference in dish between the Iron headed n/a RWD (not the FWD Al headed n/a!) and turbo (FWD Al headed) pistons -
Dish specs -
(RWD 3.1 Iron Head Engine - what I've got)
COMP: (2)1.50mm OIL: (1)4.00mm
COMP DIST: 1.442"; PIN DIA: .9055"
RECESSED HEAD .105" DEEP x 2.913" DIA
Dish specs -
(FWD Turbo 3.1 Aluminum Head Engine)
COMP: (2)1.50mm OIL: (1)4.00mm
COMP DIST: 1.442"; PIN DIA: .9055"
RECESSED HEAD .265" DEEP x 3.000" DIA
The FWD 3.1 pistons will work... but WAY too low a compression to be of any use to me..... 7:1 or so. I'd like about 8:1 or so. Does Mahle make a RWD 3.1 iron headed piston? Or, a 3.1 piston (3.539" bore - .030" over) with about a 12-14cc dish?
Found the Mahle pistons for my application - #027250, vs your 027260. Now the question - are the same beefy construction? I'll call tomorrow. Does anyone here know?
$108 - Mahle Pistons p/n #027250
The guy was telling me those are stock pistons for my application? Now, are they going to be the same beefy construction as the TGP # 027260? The only difference I'm seeing, is the dish....
From what I've seen of the Mahle pistons, they all have the same great cosntruction. But I can't guarantee these pistons will.
Go to the Mahle site and decide four yourself. There on the same page so I would assume they have the same charestisic. Didn't see one that suits you perfectly although there is a 599810 with no specs.
Be carefull. Who ever gave you that 3'' dish distance for the 60 piston is wrong. It's 2.795 on the std and +.040. The distance for the 50 could be wrong to. Thats the one spec that I couldn't find on ther site. In the picture they look the same.
http://www.mahleinc.com/obj.nsf/479CBD429BAE04CA85256C390040EBE1/$FILE/2003-04%20MAHLE%20CATALOG%20P.15-60.pdf
http://www.mahleinc.com/am_na/am_na.nsf/out/1.5.0.0?OpenDocument&6,447571E-02
Jud
I believe you could use the GEN III 3100 piston design if you desire to stick with a hyper rather than forged using the iron heads.
They offer an increased compressed height over the 3.1 MPFI piston, which results in a static compression ratio increase with aluminum heads from 8.9:1 to 9.6:1.
Pretty safe to assume that this 0.7 increase would also apply
when an iron head is used rather than the alum. head.
Using the 3.1 MPFI piston (either NA or TGP) with iron heads will result in a cr (< 7:1) which is really not advantageous for anything other than a high boosted strip application, since it would not be very steeetable due to the lack of off boost torque.
The 0.7 increase would not just make this a more feasible approach from a cr standpoint, the increased compressed height was employed when GM finally caught on to the fact that optimized piston quench was actually an important factor in engine design. :)
Thus, by using the GEN III piston design with iron heads, your quench height should also be close to optimized.
Optimized quench translates into a decreased detonation threshold, which allows one to obtain a marked increase in boost levels without the corresponding increase in fuel octane that would normally apply.