What are the limits

[Younggun88]

o.k so what are the mechanical limits of the 3500(LX9). What is keeping the engine from say 7,500rpm and 15psi of boost. Custom pistons, Connecting rods, crank, valvetrain. What all would be needed. Also i would use methanol injection and a intercooler to keep knock down. i am just trying to see how far the limits can be pushed.

[Ortie666]

I would have to say #1 good rod and main bolts to get rid of stretching witch stock bolts are prone to doing.. #2 Propper fuel mapping, and a timing curve tune.. #3 Forged pistons, But olny if you want it to last.. and #4 Windage tray & crank scraper to keep suficiant oil in the pan at the higher Rpm's.. There Is a couple more Oiling tricks one can do.. but then your getting into machining the block and crank.. Ive held a stock-ish 2.8L down straights to 7200 rpm with no problems.. Cant say that 300 more rpm in a better built v6 would be any problem

[Superdave]

the 3500 comes with the same windage tray that the 3400 has.. so that's covered. The crank is very strong.. weak link is the pistons, rods, valvetrain and timing chain.

I've had my 3500 above 7K RPM quite a few times (almost every 1-2 shift).

[1988GTU]

IMO I would rather keep the R's around 6000-6500 and just up the boost a little more to 16-18 psi. It's a pushrod engine not a dohc.

Ive held a stock-ish 2.8L down straights to 7200 rpm with no problems..

WHY! would you want to even do that? Was there some sort of boost helping it take in more air?

[Younggun88]

But that is the point i want to push the limits. Money is not the issue i simply am trying to find out how far you can push it.

[Ortie666]

WHY! would you want to even do that? Was there some sort of boost helping it take in more air?

???Beacause I RoadRace the car on weekends and holding a gear to a corner is faster than shifting, Or because I can.. Besides a 420cfm carb and scoop, Its the exhast that plays the biggest roll in making power that high.. When I put single 2.5 inch and a muffler on it wont even rev past 6500 in neutral..

[Younggun88]

after looking at some desktop dyno numbers there is no gain from anything above 7300 with the cam i am looking at so 7300 plus 15psi of boost looking for about 450whp, 0-60 under 3.5s and 1/4 mile under 11.5. BTW this is going in a Fiero so i have much better traction and weight distribution than a FWD. My goal is to build a car with specs like the Ferrari 430 Scuderia. This should get me close. I also have been looking into ECU's with Flat shifts, Meth and Boost control for a complete custom setup. It will be costly but i will build it over a 4 to 5 year period once i get out of college and get a good job.

[MidnightriderZ24]

@ 10 psi i made 358 to the wheels with a decent tune (needed more work) on a 3400. after a retune running 12psi and other mods i can gaurantee i was putting almost 400 to the wheels and thats with a stock cam. when i pulled my engine apart, there wasnt really and issues at all, bearings looked decent.. the only thing is the walls were SCORED like no other. you will have no problem if u change out the rods, powered metal rods are strong, but very brittle, seeing those rpms you WILL stretch them (ask whitelightning). u will need some headwork to support those rpms! u will reach your goal no doubt at all.. just remember, better to be safe then sorry..

[923.4v6]

what kind of lift is the 3500 valve springs good for and compare against the yellow LS springs?

[Superdave]

what kind of lift is the 3500 valve springs good for and compare against the yellow LS springs?

the 3500 springs are good for around .440 lift no more than that. The Yellow LS6's coil bind at .560 which makes safe lift around .510 or so..

[1meanz]

whatever you do, if you go for 15 psi at 7500 rpm, then get videos! and if it holds 15, go 20! LOL but ALAWYS get a video, i want to see it if it doesent hold lol

[mcgavinz26]

This may seem like a stupid question, but just go with it. No one ever mentions lifters. They are hydrolic in all the 60 degree engines aren't they? I thought the idea behind them was that at higher rpms you will start to loose valve lift because of them, sort of a safety thing. Right or wrong? Stock ones are good enough for anything or you want solid lifters to run higher rpms?

[Superdave]

This may seem like a stupid question, but just go with it. No one ever mentions lifters. They are hydrolic in all the 60 degree engines aren't they? I thought the idea behind them was that at higher rpms you will start to loose valve lift because of them, sort of a safety thing. Right or wrong? Stock ones are good enough for anything or you want solid lifters to run higher rpms?

there are ways to improve the 3400 lifters, i'm actually working on a how-to video for this right now.

[bbeck]

solids do have a sweet ass sound... could it cause any issues with the knock sensors?

[Ortie666]

yeah, they also could cause my new motor that I dont speak of to rev 8+ all day