poor_red_neck

Ok, this should be the last question I ask for quite a while, until I get the FC, and it starts messing up


I tried searching for this, but there were so many results, it would take forever to find it.

The engine in my S5 GTU is 88 block and rotors, with 89 intake and 'accessories' etc etc

I'm pondering if to sell the S4 motor, complete as is, and buy a complete S5 engine, hopefully a re-built with low miles

Or

Port my existing motor, and while Im at it (this is a question, not a statement) Can I replace the rotors with S5 rotors to get the HP from a stock S5 engine? Or does the entire block need to be replaced?
I currently have all the S5 stuff on it. (this is according to the current owner, im assuming the TB and everything else is S5 ) Is the S4 and S5 "block" the same? I know the rotors are different, and the S5 are lighter I believe... is this the only thing holding my HP back to 146 instead of 160? If so, is it as simple as putting in S5 rotors (with the right letter code, as in weight, i do know about that) and get to that 160 HP #?



How should I go about this?

My first method, I have a stock S5 motor, probably won't port it, as I just laid down bucks for a new motor.

Or second (assuming I can simply exchange rotors) port the motor, etc.


My current mods are CAI, exaust, S-AFC.

If I go, I'll be going for a slightly 'large' street port.

I'm really not that familiar with this, and hoping to get the opinions from some of you that may have been in my situation... or can shed some light.


If you need any clarificatoin, let me know.

Thank you so much,
Jonathan

poor_red_neck

By the way, the S4/S5 hybrid currently in it has around 30K miles on it since the rebuild.

13bpower

The internal (seals, rotors, housings) of the s4 engine are not designed to be reved to 8k, the s5 internals are.

If you want more power go with a COMPLETE s5 engine and a streetport. Don't do it half way if your going to do it.

Basically if your reason for swapping is to get more power it is not worth it UNLESS you streetport it at the same time. AND do it the right way, with all s5 stuff. You will be much happier in the long run.

poor_red_neck

Well, either way I was going to port the S4 motor in it at the moment.

I wasn't planning on porting a S5 motor in the beginning for the reason that I would need to get a re-build kit, and I honestly don't feel confident enough to do a porting job. I don't know how to do it, and don't trust my dremel skillz (If thats whats used )

What all is replaced during a rebuild? Side seals, apex seals, and more seals probably (dont know all the names yet) Is that pretty much all there is to it?

If anyone has a good write up on porting, Id love to read it. I've been following 88IntegraLS's write up, but Id be worried that one housing would be different than the other... just too much I couldnt afford if I screwed up.


How much would a S5 motor run me... full thing.
Would it matter if it is "blown." I dont know if buying a blown motor, if I could risk having rotor housing damage.

If I get a S5, I will most likely go ahead and get a port done. - So looks like Im going with a S5 motor

poor_red_neck

Bumpity Bump...
This forum moves too damn fast

Icemark

And what are you asking, that you are bumping up???

didn't you answer your own questions with:

poor_red_neck

Im asking if I were to purchase a "blown" S5 motor, does this usually mean it has rotor housing damage... or just a blown seal, or both. Since I'm going to port it, and have to replace all the seals, if it would matter that it is blown. Do rotor housings normally get messed up during apex seal failure, or just the apex seal break, and lose compression.

How much does a S5 long-block go for, doesnt matter mileage as it will be rebuilt anyways. What's a fair price on a S5 blown motor (considering no rotor housing damage, if thats possible)

Icemark

Blown motor, could be a simple as a water seal or oil seal that let go, or as bad as an apex seal let go.

If it is an apex seal almost always (and occasionally on water seals) the housing will need to be replaced, and a good number of times the rotor itself as well.

Blown motors can be a cheap as free or as expensive as a couple hundred.

poor_red_neck

So in your opinion, would it be better to just buy a S5 long-block with moderately high mileage? Port it, replace all seals (rebuild I guess) put my S-AFC back on, exaust etc.

Also, my current exaust is bonez cat, 2.5" catback, magnaflow mufflers...

If I were to change to RB true duals, full package, would I need to re-tune the S-AFC?

Thanks again Mark,
Jonathan

Fitness Stain

u got a series 4 engine, and a series 5 lower and upper intake right?

how did you get those to match up as they are different...atleast the gaskets are....
i have a series 4 engine with a series 5 jspec upper and lower intake, and i want to use them on the series 4 engine.....
i dont want to go the port matching route unless i have to as i think it will take time and right now...time is not on my side

poor_red_neck

OH man, lol.... I just raised a few BS flags about 10 minutes before reading this post...

**EDIT** Any work currently done on the engine, has been done by the current owner, I have not done anything as of yet, it is not in my possesion, but will be within a week or two.

I do not have the car in my possesion yet, but this is gonna be my car, no matter what, Im just saving tha last bit of money to pay for her.



This is what I dont get.

It's a S4 Block and rotors, with S5 intake right?

Well, I just rememberd something, the S5 throttle body doesn't even fit the S4... not without modifications, and he didnt mention modifying any of the parts. Im not sure about the UIM or LIM.... this is raising a few brows for me as well.

He claims that having the S5 intake will get a few HP back, from the 146 of the S4... this may be so, but I **think** he might be pulling my leg onthis one, and It's just a plain S4 motor. I'm pretty sure its not a J-Spec.

Thanks for bringing that up, definately something to bring up when we finalise the deal.



Next question:

If the throttle body has been modified to fit on the S4 engine, can it still be placed on a S5.

Here's something I just thought about.

I buy a S5 short-block, streetport the shortblock, take all the existing S5 stuff (with the assumption that the TB, IMs, etc etc all will still fit) and put that engine in my car.

This way, if for some reason the S5 ported short block will blow, I have a S4 short block that I can just swap in there. Not as easy as just having two seperate engines, but I honestly don't have any room for an entire S4 engine to lay around, but just the block wouldn't be that hard.

It *should* be cheaper this way. May be a bit more difficult, and take longer to install, but I don't really care about the time.


Am I making sense, or is this all a bunch of crap Im thinking, and wont work

poor_red_neck

OK....

Last question for this thread:


The shortblock is S4
The lower intake manifold is S4
Everything else is S5

He has a bunch of extra parts, including the original S5 LIM...

So all I would have to do is buy a S5 shortblock, port it, slap it in the engine, done

And I'll have the S4 shortblock and LIM as "backup" incase the S5 blows...


This WILL work correct?

If so, sounds like the plan Im going to do.

Thanks for everybody's help,

Jonathan

Icemark

Actually if you drill the S5 middle (VDI section) intake,

do a minor porting job to increase the S5 intake runners and use a S4 gasket, it fits just fine.

That way you can keep the S4 lower intake with its aux port activation, and then add the VDI middle and upper sections.

It still requires you to use either a S5 main and 2ndary fuel rail (or swap the PD to the other side on the S4 main rail). This is why you need to use either the S5 rail or swap the PD to the other side:


But otherwise it will work fine.

Icemark

If the car is a S4 I would keep with the S4 block. If the car is a S5, then I'd swap over to the S5 block.

The compression difference is pretty minor, but you gain RPM using the S5 block and flywheel (you don't want to use the S4 flywheel with the S5 engine and rev it past 7500). The extra RPM at the top end is the only reason to use the S5 block. The HP gains you have already from using the S5 intake on the S4 block.

poor_red_neck

Yes, its a 89 GTU


So you're saying that It does indeed have at/around 160 HP (if it was in new condition)... just can't rev to 8K (I know the redline is 7K)

Awesome

I think I'll do it just for the fact of porting the engine easier (dont know where I get that from... sounded right in my mind at the time) and the RPM might provide some kind of an advantage...


THANKS A MILLION MARK!
Jonathan

Icemark

Normally you would use a slightly modified S4 throttle body, if the car was a S4. You would only use a S5 throttle body if you were useing a S5 ECU.

Quote:

Next question:

If the throttle body has been modified to fit on the S4 engine, can it still be placed on a S5.

Yes, the fittement issue is one of the S4 throttle body on a S5 upper intake, and a S4 block. Minor grinding is required of the S4 block to fit the S5 intake and S4 throttle body.

Quote:

Here's something I just thought about.

I buy a S5 short-block, streetport the shortblock, take all the existing S5 stuff (with the assumption that the TB, IMs, etc etc all will still fit) and put that engine in my car.

This way, if for some reason the S5 ported short block will blow, I have a S4 short block that I can just swap in there. Not as easy as just having two seperate engines, but I honestly don't have any room for an entire S4 engine to lay around, but just the block wouldn't be that hard.

It *should* be cheaper this way. May be a bit more difficult, and take longer to install, but I don't really care about the time.


Am I making sense, or is this all a bunch of crap Im thinking, and wont work

Again it will depend on the series car. More work and not an easy swap if the car is a S5 and using a S4 block. MOP comes to mind first, as the S5 MOP is electronic and electronicly controlled.

Icemark

Dyno tests have been consistently showing about a 10-15 HP increase over the stock 146 of a S4 block, when using the S5 VDI intake (of course that is dependent on the engine condition to start with, as well as other mods already done on the car).

poor_red_neck

Good Deal!

Well, current mods are:

Ghetto cold air intake, soon to be fitted with a "true" cold air intake... I dont know if that's what its called, but its where the intake is coming in from the bumper... like, the filter is down on the bumper... I think RB has one, but I'm getting my hands on one from 1989RX7Guy (currently under testing)

Bonez Cat
2.5" Cat Back
MagnaFlow Mufflers
Apexi S-AFC II (not tuned yet, but will be soon)

Ok Mark...

Very sorry, I just remembered another fact I'd like to know...

Will porting (streetport) have the same effect HP wise on a S4 as a S5 block? Will there be a greater HP increase porting a S5 instead of a S4?

Thanks,

Jonathan

Icemark

You'll have more HP with street porting a S5 block, because of the higher compression rotor faces.

Fitness Stain

but mines a turbo...does the same still apply?