From what I've heard, the DOHC 3.4 (LQ1) pistons are worth 10:1 in a 3.4 block. Your cam ought to be happy with that, based upon specs.
I'm wondering about the need for SFI, and a different ECM, though. My 3.4 was quite possibly 200+ HP, ran 19# injectors, a 272, was ported and had high flow intake and exhaust - and it ran fine on the stock ECM. Actually, it even ran okay - albeit a bit rich - on the stock chip. (Ran well enough to pass Atlanta emissions testing, though.) I wouldn't bother changing ECMs unless you want to go DIS.
From what I've heard, the DOHC 3.4 (LQ1) pistons are worth 10:1 in a 3.4 block. Your cam ought to be happy with that, based upon specs.
I'm wondering about the need for SFI, and a different ECM, though. My 3.4 was quite possibly 200+ HP, ran 19# injectors, a 272, was ported and had high flow intake and exhaust - and it ran fine on the stock ECM. Actually, it even ran okay - albeit a bit rich - on the stock chip. (Ran well enough to pass Atlanta emissions testing, though.) I wouldn't bother changing ECMs unless you want to go DIS.
Thanks Radar, my Fiero drove pretty well before (aside from the wiped cam lobe), but I think I'm just looking to make it run more efficiently and reliably. I want to disable the EGR, probably even the cold-start injector, etc. I'm thinking the MegaSquirt, or the FastEFI. I have both... but more than anything else, I just want a whole new harness. I'll be breaking in the motor with the old harness and ECM. So it's not something I'll do immediately. I just want to be able to have the AFR tuned in perfectly across the board. I want the engine to perform / feel like a new car, and not have any hunting idle issues, or anything like that. There are "some" characteristics of the Fiero I want to forget, haha...
Thanks for the heads up on the 3.4 DOHC pistons! I'll take a look at that...
[This message has been edited by 82-T/A [At Work] (edited 04-16-2024).]
Originally posted by 82-T/A [At Work]: Thanks Radar, my Fiero drove pretty well before (aside from the wiped cam lobe), but I think I'm just looking to make it run more efficiently and reliably. I want to disable the EGR, probably even the cold-start injector, etc. I'm thinking the MegaSquirt, or the FastEFI. I have both... but more than anything else, I just want a whole new harness. I'll be breaking in the motor with the old harness and ECM. So it's not something I'll do immediately. I just want to be able to have the AFR tuned in perfectly across the board. I want the engine to perform / feel like a new car, and not have any hunting idle issues, or anything like that. There are "some" characteristics of the Fiero I want to forget, haha...
Thanks for the heads up on the 3.4 DOHC pistons! I'll take a look at that...
...which I've used for years... ...and if you want to bore it to 3.5L (3.7" / 94 mm bore diameter), you can use LFX 3.6L DOHC pistons.
[This message has been edited by lou_dias (edited 04-16-2024).]
Hey guys... rather than create a new thread, I figured I'd continue to compound my questions on this one. I made this post last year, and then some ago... and not sure what all I mentioned above, but I ordered a DCC9 / L32 crate motor (rebuilt engine) last spring. This is what I have SO FAR for my build:
3.4 V6/60 block (93-95 Camaro or Firebird engine) - ARI Racing Ported Gen-1 heads (what they called a mild performance porting and blending), with all new high performance springs, the works... - SI Stainless Steel "tulip?" valves to improve a bit more air flow into the combustion chamber - Crane H272 Camshaft w/ Crower hydraulic "cam saver" lifters - LQ1 DOHC Pistons (.020 overbore) ... roughly to give me ~9.7:1 compression or better. - 17# Accel pintle-style injectors - Port matching of the intake, runners, and the plenum (I might even spring for extrude-honing) - Darrel Morse bored throttle body, and will eventually do the DAWG mod (that's not done yet) - West Coast Fiero stainless steel shorty headers - 2.5" complete stainless mandrel-bent cat-back exhaust system with a high-flow Magnaflow stainless steel catalytic converter
I might be missing a few things, but that's basically what I'm looking at. Now, I'm planning on taking everything to the machine shop, and I have questions:
- I have not yet ordered rings for the pistons I've purchased. What is the BEST (highest performance, lowest wear to the block, and most reliable) rings I should get (either make and / or type)
- What kind of bearings should I get, or are there any that I should stay away from? I know most of them are aluminum, are there any with special coatings or... something I want to stay away from?
- I'm planning on using the stock rods that are currently with the 3.4 block and the stock crank. Is there a better replacement for either... or more specifically, are there better aftermarket rods I should be using instead? Just want to make sure that I use the best I can while I have the motor open.
- When I take my engine to the machine shop to have the rotating assembly balanced... is there anything that I should ask them to ensure that it's balanced exceptionally well? They may look at this as just a commuter car engine. I'll of course tell them my goals... but is there more I can tell them than simply, "here... balance this." Like, can I specify... to within half a gram, or something like that?
I know people have different opinions on these things. But just so everyone knows where I am on this. This is my "high school" car, and effectively also my dream car (if you may...). So, for things that go into the engine, and things I can't really just swap out in an afternoon, I don't mind spending whatever it takes to get the absolute best of the best of the best. I want to produce the most horsepower, with the best reliability, all while looking totally stock to the untrained eye. So that means a 3.4 block with all the stock 2.8 bits bolted on.
I'm expecting ~200hp, but hoping to get more like 210, don't know if I'll be there, but we'll see. I'd like to see reliable mid-14s in the quarter with my hybrid SCX-282/Fiero Getrag. Thank you!!!
