been around 420a's for a long while. been on this site for a long while as well. I don't post alot unless I have a really good question. The title says it all. The motor'll handle it, just curious about the tranny. I've done the most I can w/ the a604. Tranny temp gauge, 4 or 6 pass cooler (can't remember), relatively new a604. It's a 99 model so I know it's the most recent design. I'll never do more than 9 psi on first gear, but when it shifts to second, will it handle 16 or more? 20? Want to know some of the senior 2gnt'ers opinions on this. I'm slowly getting parts for a manual swap, but I need advice. money is tight so don't suggest to swap yet. Tell me about what the a604 can do for ME. lol Thanks :)

doubtful.

Stock clutch packs arent known for holding to a lot of abuse NA, let alone when you start doubling the power.

stock clutch hubs are also know for shearing in NA trim. (turbo pt cruiser hubs are newer design and should hold up much better...shame they werent available when I built my a604...this is what happened to my built a604 and why i did the 5spd swap)

Does the 99 trans come with aluminum accumlators? If not, the OEM plastic accumulators are known to crack (which leads to burnt up clutches as pressure decreases)



Not saying it WILL blow, I would just be ready for it.

i say save up and buy the parts for the 5speed swap. then once you have everything turn up the boost and let us know how the auto try handles it

I wouldnt even consider it unless you built the atx up. I did a shitload of work to mine, changed all the internals even had some things custom made so that they wouldnt break. But I wouldnt turn it up that high either way.

I would imagine by most ppl's responses is no, its dumb. I don't really have a choice right now though. I'm about to be built (motor) and wanna drop it in and go. On the other hand, I believe I have all the parts for the 5 speed swap except for the actual transmission w/ brackets itself. That's not something i'd like to handle right now. I'd like to get the motor in, broken in, and run everything smoothly, THEN I will worry about the 5 spd swap.

I want to know the limits on the a604. I want to know what is dumb and what is not. I want to know what to avoid and what not to avoid. I'm not a nooob on the a604, i know it can handle some hp/torque, but not everything that is thrown at it. I want to know limits on OEM a604's (newer 99 design). I need advice on what to do with that in mind. No I will not swap extremely soon, and no I will not build the a604. I want high boost, but just not enough to break the tranny. Just tell me what would hold for some time. 15 psi? 12 psi? 50 psi? lol

I hope this helps to clear out the answers that i'm looking for. I appreciate everyones replies and will take everything that is said into consideration 4 my decision.

Just for clarification, there was another a604 post about... I think the title was like "high boost..." something. I might can find the post and link it here but I asked a very general question about this there as well. Another user responded mentioning that the a604 can take it as long as its from a roll, which I will always be doing. 8psi first gear, 15 or more (depending on the tranny bogging down) in second, and so fourth... ok enough typing

here's the post I was talking about:
http://forums.2gnt.com/dcboard.php?az=show_topic&forum=33&topic_id=3571&mode=full
reply was from mcgyvr

Your not gonna get the answers you want.
Who knows the real condition of your A604.
Ryan has had issues at eleveated boost levels but others have been just fine.. There are lots of variables..
It might last just fine with 20+psi pulls or it might grenade with a 5psi pull.


Why not just keep a safe boost level (under 10psi) till you get the 5speed?
Do it right or expect problems...
Or just turn it up and blow the fuck out of the A604 for giggles and to force you to do the swap..
.
.

well, i forgot to mention that I used to run 9-10psi. I blew the motor, rebuilt it and am now running 6psi. Tranny has never slipped nor has it had any hints of a coming failure or whatnot. i guess i'll see what she does...

Never boost with O/D engaged, that's how you will burn up your clutch hub and kiss your tranny goodbye. If you are going to be doing any kind of boosting always make sure you do not have Overdrive on. Personally I wouldn't do anything above 10psi, unless the trans is built for a turbo setup.

OD is only engaged during cruising speeds. Under more than 50 or so % throttle, it never engages and it's as if it were to be off. OD does engage sometimes at the top of 2nd at full throttle, but not often. I don't think OD has anything to do with tranny strength at those boost levels. Clutch pax will probably slip or at least something will. eventually. I'm doing the 5spd swap, so no worries :)

I ran 15-18psi on my stock a604 for about 30k miles then it broke. Tranny slipped like a bad clutch when it died, and barely got it home under its own power before it just stopped going forward. It makes cool whining noises now.