2RotorSpeed

iTrader: (1)

Ok, so possibly due to partial oil metering pump failiure, my s5 tii front rotor has no compression on any of the faces... gear broke or something on those lines... no sure until I take it a part. No, it did not 'blown' up. So I will be swaping the block with a s4 NA engine with 151,000 miles one it (compression checked to be average/ok). HAH! I was running about 12-14 psi safely before (fuel and all).

So how about now? Is 10psi safe if I retard timing by 5 degrees? What would you guys run/do?

NJGreenBudd

iTrader: (1)

how long do you plan on the motor lasting?

ramses666

iTrader: (1)

I'm confused.... Your gonna swap a tII block with an NA?!? I think you need to think this over a bit... Perhaps you meant that you would borrow a NA housing and swap it with a TII. Maybe you should elaborate more of what your plans are.

Ramses666

arghx

iTrader: (3)

swapping motors between series is a pain in the ***. Don't bother, there's no point.

2RotorSpeed

iTrader: (1)

All i'm doing is changing blocks... so i'm putting the s5 turbo manifolds, turbo, everything on a s4 NA black. I know all about it, i've done this before, I know you have to tap the block for the manifold, you have to port the manifold to match the block intake ports, etc. I will have the car running again by the end of next week, just don't know for how long lol. So this isn't a question of how to do it, since I've already done this before, succesfully, it's a question of... I drift on a regular basis, and I want this motor to last at least for this season.

So, how much boost would it be safe on a 9:4 compression na motor with 150k miles, and how much timing would you retard... etc. thanks

classicauto

iTrader: (3)

First question:

You were boosting 12-14psi safely before? Then why did the engine lose compression on the front? That's not what I'd consider safe. Main thing that gives compression is your seals, nothing to do with "breaking a gear".

Second:

TII manifold won't bolt to an N/A block without some pretty serious mods. You need to add aluminum to the upper portions at the front and rear of the manifold and port the ever-loving **** out of it. Or buy a Japan2la mani already modded.
Along of course with swapping front covers and water pump assemblys.

As far as a safe level of boost for an S4 N/A....you can run a crap load of it if you can control the engine properly (standalone) but on a stock ECU I wouldn't push past stock boost levels even with jacked up methods like retarding base timing.

If you want it to last, don't put used engines in.

2RotorSpeed

iTrader: (1)

OK lol, I don't need lessons on how to turbo an n/a. The front rotor failed due to oil metering pump failiure. Now I'm going premix. Yes, at 13-14 psi I was safe, I have a wideband, safc, 720cc secondaries, AFR in the 11.5 across the band a WOT. So, I just wanted to know what people would run as a safe boost level, now can someone please just answer my question and stop asking me questions lol. Thanks

classicauto

iTrader: (3)

If that were true, then you don't need to ask the question you asked.

As I said, I wouldn't go much above stock without a proper way to control whats going on in the engine. But if you feel 14psi was safe on the stock turbo with S5 rotors, then trim a little boost out for the higher comp. Although, its well known that the stock turbo isn't doing much past 12psi.

Juiceh

iTrader: (4)

S5 TII to S4 NA block swap?

Instead of doing that why don't you tear apart half the current engine and see if you can fix that engine instead? Maybe all you need is to pop 3 new seals in and your all set...

*edit*
In response to the original question, I would not boost it at all. I'd pull it and tear it down asap. Driving around on it now probably won't cause any more damage, but ya never know.

2RotorSpeed

iTrader: (1)

Ok, I was just asking for an opinion about how much boost to run or if I should retard any timing just due to the old milage on the engine. I obviously do know how to turbo an NA since I've done it before... so I'm not sure why we're having this argument. I will run 10psi on this NA, and hope for the best. Do you recommend retarding timing at all? From what I know all blocks have the same base timing 5 deg and 20 deg, then the ECUs do the rest. I will be running the N370 ECU (and knock sensor), so there is probably no reason to retard timing unless it might help conserve a high milage motor... what you guys think?
Thanks.

classicauto

iTrader: (3)

Retarding the base timing will make it "safer" under boost, but you're going to run slugishly everywhere else, and be on the richer side across the board due to timing's effect on fuel requirements.

Aaron Cake

iTrader: (1)

With the stock turbo, 12 PSI. After that it's pointless because of the 150+ degree intake temps. Pull two degrees of timing for every PSI of boost. Have fun trying to do this with the stock ECU.

The knock sensor will not help you.

2RotorSpeed

iTrader: (1)

Well like I said I'll be using the N370 ECU, which pulls timing based on boost already. So what I got from your responses is... don't change base timing, and the amount of boost I'll be running won't make much of a difference as long as I'm running safe AFRs.... even with a 150k 9:4 compression engine. Corrcet?

Aaron Cake

iTrader: (1)

The stock turbo starts to die around 12 PSI. That is the most you want to push it to avoid heating the intake charge to insane levels.

At 12 PSI on the stock turbo, using S4 rotors, you will want to run a maximum of 15 degrees advance to keep things reliable. Bring that down to 12 degrees and it will be nearly impossible to blow up.

2RotorSpeed

iTrader: (1)

Ok, so I got the 150k miles s4 NA motor runing with all my other s5 turboparts. I didn't retard base timing yet (only drove car 15miles and didn't go past 2psi of boost). My turbo got slightly dameged when my engine blew a week ago, and I need to get it at least rebalanced before I can drift or even drive the car for a long period of time. My question is, should I bother retarding BASE timing 5deg if I plan on running 10psi? (I'm running N370 ECU). I know you, aron cake made your na turbo and didn't retard timing at all in the begining and your car ran fine...