So I trashed my head. Time to upgrade.

[dsm-onster]

I'm finally home. I bent many, many valves. My timing belt tensioner desided to throw in the towel.

I've been told that the stock valve train is not the weak link to revving the engine to higher than stock levels. SOOOOO, i'm going to get some FP2s, get some new stock springs, and any new stock valves i need. MY question is, if i keep my stock intake mani, will that defeat the purpose of raising the rev limit completely?More importantly, if I keep my stock intake mani, will it choke me out up top so much that it will take away the benefits of the FP2s beyond 7000 rpms? I can't find the posts compairing the stock mani with aftermarket SMIMs.

 

[johnk]

If you want to raise your revs I would recommend some stiffer springs. Don't bother replacing the valves yourself. For starters you need a machine shop to redeck the thing and hand lapping the valves is never going to get those seats as smooth as they should be. I know I've tried. If you don't have the tool for taking out the valves and standard size compressors are too small for this head.

 

[1SloColt]

If you raise the limiter and go with the FP2s it will not choke out the topend cause of the stock intake manifold. Wouldn't be a bad idea to go with a nice sheet metal intake and FP2s with stock springs and valves at 8krpm though. Should pic up some major power under the curve with a nice manifold, but no the stock one won't choke out the topend completely.

 

[dsm-onster]

hand lapping the valves is never going to get those seats as smooth as they should be. I know I've tried. If you don't have the tool for taking out the valves and standard size compressors are too small for this head.

I figured that. I wish it were that easy .

If you want to raise your revs I would recommend some stiffer springs.

So stock springs with 8500rpm rev limit is not a good DD?

 

[Mike1992]

So stock springs with 8500rpm rev limit is not a good DD?

Um no, if ya wanna rev past the stock 7k redline on a daily basis definetely upgrade your valvetrain.

 

[dsm-onster]

If you raise the limiter and go with the FP2s it will not choke out the topend cause of the stock intake manifold. Wouldn't be a bad idea to go with a nice sheet metal intake and FP2s with stock springs and valves at 8krpm though. Should pic up some major power under the curve with a nice manifold, but no the stock one won't choke out the topend completely.

Hey, 1SloColt! I was thinking this. Maybe no 8500 but 8000 would be fine with my 18G. How's the colt? Still getting bucked aroud by those 'stangs ? FWD is a b!tch.

 

[dsm-onster]

Um no, if ya wanna rev past the stock 7k redline on a daily basis definetely upgrade your valvetrain.

Well, i don't want to run past 7000 every day. Just want to have a DD that can every once and a while. Why, in my research, do i see thread after thread of guys doing this on their daily drivers without a care for years at a time. I don't want to run it in the red all the time everday, i want a daily driver not an exploding bucket of bolts . I'm not flaming or anything i'm just .

 

[Mike1992]

Think about it with reason. Why would mitsu set a redline of 7k. You want to throw in higher lift cams and use stock springs to push the springs even deeper into rpm's. Think about it, its like a duh answer. The stock spring wont handle the higher lifts at those rpm's and you will float a valve. Do it once and do it right dont half ass it, or it will come back to bite you in the ass.

 

[scottsee]

Plenty of people have reved their stock valvetrain up to 8500 on a daily basis. Stock springs have a seat pressure of around 80lb. You wont float any valves with your comp 2 (fp2-f2x) cams. When you get into the fp3, fp3x + cams you are required to stiffen your spring seat pressure to around 90-95lb. Do though buy new lifters when you change your cams. It's highly recommended in every service book their is.

1g intake manifold flows better at 4700-6700RPM. Everywhere else it falls about 3-4lb/min short in low and high rpm ranges. Nothing significant. You can extrude hone your intake manny. You probably wont "need" to do that with an 18g. It is a good idea if you'll be going larger anytime soon.

 

[larsrya8]

You wont float any valves with your comp 2 (fp2-f2x) cams. When you get into the fp3, fp3x + cams you are required to stiffen your spring seat pressure to around 90-95lb.

Forced Performance's website shows whether upgraded valve springs should be used with their cams.

If it isn't too much more expensive to get upgraded valve springs over the stock ones, I would go with the upgraded ones. True, stock setup can handle around 8500, but if you decide to upgrade in the future you're just going to have to take it apart all over again.

 

[GVR4592]

Here's a thread from Don Polk about cylinder head flow and how a stock intake manifold is a restriction even with a completely stock cylinder head. Stock springs will most likely be fine, if not you can shim them for more pressure. Just be careful of coil bind when shimming your stock springs.
http://www.dsmtuners.com/forums/showthread.php?t=16920

And stock springs have a seat pressure of about 55 lbs at 1.60 installed height, not 85.

 

[dsm-onster]

Here's a thread from Don Polk about cylinder head flow and how a stock intake manifold is a restriction even with a completely stock cylinder head. Stock springs will most likely be fine, if not you can shim them for more pressure. Just be careful of coil bind when shimming your stock springs.
http://www.dsmtuners.com/forums/showthread.php?t=16920

And stock springs have a seat pressure of about 55 lbs at 1.60 installed height, not 85.

I came across that thread last night. I was glad I did. I have to say that what you are saying is what most people say. I don't know how often John Shepard had to replace his springs but he did used shimmed stockers until recently. How much is a safe but effective shim width? .020", .040", .060"

If i have to get performance springs to get to 8500 rpms then i'm getting the FP2x cam. I might as well go for the higher lift. Unless i can't go to 8500 with the higher lift.

 

[dsm-onster]

Do though buy new lifters when you change your cams. It's highly recommended in every service book their is.

Hey, do you mean rocker arms? That's what i see, but thats for non-roller valvetrains. Since we have roller rockers, we don't need to replace those usually, right?

 

[aero_sallee]

Hey, do you mean rocker arms? That's what i see, but thats for non-roller valvetrains. Since we have roller rockers, we don't need to replace those usually, right?

They recommend replacing them with the revised 3g revised lifters to eliminate the dreaded DSM lifter tick.

 

[1SloColt]

Hey, 1SloColt! I was thinking this. Maybe no 8500 but 8000 would be fine with my 18G. How's the colt? Still getting bucked aroud by those 'stangs ? FWD is a b!tch.

My friend runs 264/272 combo and wraps 1st out to 8krpm while racing. I wouldn't try 8500 though. Colt is doign well, pulls pretty damn good with the SCM61 on 20psi. Doesn't leave the revlimiter until 3rd. Can't run from a deadstop cause it absolutely pointless. Tryin to conjure up a 2 stage control to relieve the spinning on the street right now. Sorry to here about the tnesioner.

 

[dsm-onster]

They recommend replacing them with the revised 3g revised lifters to eliminate the dreaded DSM lifter tick.

Oh yea. This head was rebuilt by the PO and the stockers were opened up so the oil can flow better. This is why i'd prefer not to replace them. I have no lifter tick. But that's a good idea.

I think i'm going with Manley performance springs from SBR. I never saw them and didn't know how affordable they are. This will give me the ability to rev to 8500 on track day and will let me get the most out of my future FP2s and a SMIM if i so choose to get one.

 

[dsm-onster]

My friend runs 264/272 combo and wraps 1st out to 8krpm while racing. I wouldn't try 8500 though. Colt is doign well, pulls pretty damn good with the SCM61 on 20psi. Doesn't leave the revlimiter until 3rd. Can't run from a deadstop cause it absolutely pointless. Tryin to conjure up a 2 stage control to relieve the spinning on the street right now. Sorry to here about the tnesioner.

4G63 powered Colt . . . X dollars
SCM61 . . . X dollars
Supporting fuel . . . X dollars
Miscelaneous upgrades . . . X dollars

Seeing the faces of others pulling out on to I-95 in full wheel spin with a friggin' Colt . . . PRICELESS