Rebuild advice, ka-t!

[invain]

I'm running a t3/t04E @ 7 psi right now but the car has 112k miles and compression is pretty low in the first cylinder. Car still drives fine for now but I know it's a ticking time bomb running around boosted.

I'm obviosuly going to do a rebuild real soon, but I'm not sure how crazy I should go with a 300-350 hp goal. I don't plan on racing with the car, it'll be a dd in the summer so I most likely won't be pushing the car much. You guys think I'd need forged internals? I've heard stock internals are good up to like 400 hp? I'd like to get a decent cheap rebuild kit with just the essentials and then shop around for the other stuff to try and save a lil money. I'll be doing all the work myself, you guys think I can get it rebuilt to hold 350 hp for around $1,000? (Not including a re-tune)

[lflkajfj12123]

stock internals will not hold up to 400 hp lol

[DreamN]

^ If it's a healthy motor with a proper tune they most certainly will. Though I would never risk it with that high of horsepower.

[QuickSpoolSR]

at least upgrade the bearings, and i would upgrade the rods..

[[email protected]]

i think i heard somewhere that stock rods with forged pistons will hold up to like 350-400 reliably. someone correct me if im wrong

[invain]

stock internals will not hold up to 400 hp lol
I've heard about people pushing 500 hp on stock internals. Obviously that wouldn't last long, not the point however.

I've also read conflicting statements about the pistons/rods being the weakest link. Some say the rods are fine and pistons should be upgraded first. Others say stock pistons can hold more and rods should be upgraded first.

Like I said, my goal is 300 - 350 hp, but it'll be a DD more than anything so I won't be hitting high boost very often. I'm looking for the cheapest rebuild while still keeping it farily reliable. Doesn't have to be bulletproof, if 300 hp isn't enough I'd like to eventually do an LS1 swap.

[DreamN]

The pistons are the weakest link from what I've read. Rods are forged so they can hold their own quite well. Do a stock rebuild with upgraded pistons and arp studs. For added safety I'd go with a metal headgasket as well. The rest depends on a good tune plus what your turbo setup is.

[invain]

You sure stock rods are forged? I've honestly never heard that. From everything I've read, the rods are the first to go when stock internals are really pushed, but like I said I've also heard some people say the opposite.

[Shadowhunter]

The problem is not your horsepower goal but the compression that you are creating with a turbo in the cylinders and the stress you are putting on the internals. This is why Internals should be upgraded. Doing things right the first time pays off. That is why even if your running 6psi on stock internals will it last? Probably, but it will last much longer if you upgraded those internals.

[Ktown_drifter]

the pistons are the weak link.. 2 things about them that are reasons they should be upgraded.. 1: weak ring lands so the detonate right off... 2: high comp. Get some good low comp pistons and stock everything else with some good studs and a metal head gasket and youll be laughing

[lflkajfj12123]

The problem is not your horsepower goal but the compression that you are creating with a turbo in the cylinders and the stress you are putting on the internals. This is why Internals should be upgraded. Doing things right the first time pays off. That is why even if your running 6psi on stock internals will it last? Probably, but it will last much longer if you upgraded those internals.

you could do 400hp on stock internals i know but its a dumb idea

sr's hold up to the good till 400 on stock internals

after 300 on a ka i wouldnt risk it

especially since ka's are all fucking moody

tommy and matt both run ka-t and have upgraded their internals i think they're both at 300+ now

do it right and don't blow the motor

[dsc4130]

the rods were shot peened from the factory they are not forged, like ktown said, new pistons, good set of bearings, arp head studs refresh the head, and ive heard that the felpro HG is better thean a metal HG but im not a ka-t guy. these are things ive just gathere over the years

[ManoNegra]

the pistons are the weak link.. 2 things about them that are reasons they should be upgraded.. 1: weak ring lands so the detonate right off... 2: high comp. Get some good low comp pistons and stock everything else with some good studs and a metal head gasket and youll be laughing

we've added a detonation groove before the rings to pistons, something we've picked up from Porsche for this very reason

also, from experience, the rod end bearings are the weakest link in KAs
I'd throw some good bearings all around and upgraded rod bolts.

and lastly, bad tuning is what usually kills ka-ts.

[orion::S14]

The pistons are the weakest link...

Correct.

You sure stock rods are forged?

Yes, I'm sure. They are very strong.

the pistons are the weak link.. 2 things about them that are reasons they should be upgraded.. 1: weak ring lands so the detonate right off...

Correct.

...and lastly, bad tuning is what usually kills ka-ts.

1000% correct.

...

My advice, if you want a semi-bullet-proof ~350rwhp on a budget:

Rebuild with forged pistons, and keep the stock rods <-- They will be fine.

I've been making ~325rwhp on a 100% stock KA (with JWT cams) for YEARS now (like, +6 years, with TONS of track events each year). Like ManoNegra said...with a good tune, the stock KA will take +300rwhp NO PROBLEM.

350 is the upper limit, IMO...but again, with a good tune, and ESPECIALLY with forged pistons...you'll be set.

- Brian

[invain]

Thanks for all the replies so far guys. I'll def. go with forged pistons if they are the weakest link. If I'm way under budget maybe I'll get some eagle rods too.

And I agree a good tune is the most important. I'll def. have it retuned after the rebuild.

[invain]

What cr would you guys recommend for the pistons? I'll probably have the block bored .02 over or so.

[silviaguy240]

most all turbo applications you want to be as close to 9:1cr.

[99maxgtr]

Correct.



Yes, I'm sure. They are very strong.



Correct.



1000% correct.

...

My advice, if you want a semi-bullet-proof ~350rwhp on a budget:

Rebuild with forged pistons, and keep the stock rods <-- They will be fine.

I've been making ~325rwhp on a 100% stock KA (with JWT cams) for YEARS now (like, +6 years, with TONS of track events each year). Like ManoNegra said...with a good tune, the stock KA will take +300rwhp NO PROBLEM.

350 is the upper limit, IMO...but again, with a good tune, and ESPECIALLY with forged pistons...you'll be set.

- Brian

im all stock as well, just bought a healthy low mileage ka and hot tanked it and cleaned it up, put some arp headstuds and cometic headgasket.
im pushing probalby similar numbers as brian at 10psi on a t3/t4.
but tuning is key for sure.

[Leo-kun]

So would guys leave the stock internals alone if achieving a goal of about 280-300 hp on a KA?

[KA-T_240]

^As long as you have a solid motor with good compression.

I would not think twice about running 300whp on stock block.

[s13 @ fullboost]

not trying to thread jack but since it seems like your question was answered I also have one. Have any of you gone with the cx racing kit and what did or do you think of it?

[pinkarrowsnow]

One suggestion if your going to rebuild it please dont waste your time just not doing it correct i mean whats a few more weeks of saving ya know cp pistons eagle rods arp studs cometic gasket clevite bearings thats a pretty bomb proof motor for around 1200 bucks. Hit up tyler at underground motorsports he will give you a extremely good deal on a kit.

[undesiredshoe]

and lastly, bad tuning is what usually kills ka-ts.

Couldnt agree more. Im running 18 psi on a completely stock block sohc, never been opened up before and its running fine and its all because of what i use to tune it with. None of that piggyback shit, my motor wouldve blown a long time ago if i was using something like that.

My sohc is on the verge of 300hp right now, I have no doubt that if i had a dohc at 18 psi, i would definately be well over 350hp right now.

:bowdown:ka-t:bowdown:

[Bushido]

^ what do you use for engine mgmt?

[lflkajfj12123]

^ what do you use for engine mgmt?

id also like to know, jwt tune?

[undesiredshoe]

Chipped Stanza ecu with custom $30 realtime board from eccs.hybridka.com...$50 engine management...lol. Just a street tune right now so theres even more power to be made. Im pretty confident that with bigger injectors, i could run 25 psi or more with the stock headgasket and headstuds though the sohc head flows like a fat kid with asthma...thats whats really restricting me right now.

[lflkajfj12123]

sounds complicated

i'll take chances blowing it up with a safc-II or just go jwt

[undesiredshoe]

sounds complicated

i'll take chances blowing it up with a safc-II or just go jwt

$50 compared to a jwt $300+ and i can change everything on my own instead of waiting weeks for a retune. :coold:

But I would do a jwt tune over a safc anyday, even though the safc makes it look like you are a tuning pro.

[awesomenick]

That Stanza ECU stuff has always tempted me.

Right now I'm running a stock DOHC #28 ecu with a PLMS basic board. No realtime, sucks.

Maybe I'll switch over. I'll have to stop lurking the hybridka forums and make an account.

[Bushido]

hmmm, very interesting stuff indeed.