Hey Gang,
At the risk of starting another flamewar, I am going to ask the engine gurus if the effort of converting an S5 TII engine with 50k miles to go into an S4 TII is worth it?
You may have read the thread about my stupid purchase mistake, but would like your input as I make decision about what to do.
My last post had lots of specifics of how-to, but I'd like a real-world opinion on whether or not it's worth doing. Do you get enough benefit?

Thanks a million

- k -

 

Well now that you know exactly what has to be done to make it work, you need to decide if it's more hassle to either do the swap or try to sell the S5 engine and find a suitable S4 one. If the S5 enigne is a good one, I'd go with the swap...

 

i would just do the swap. The s5 tii motor has a better wastegate setup, and makes more power.

 

True, but the S5 turbo is a direct swap onto an S4, so that's not a reason to swap an engine. Most of the extra power comes from the ECU's electronic boost control running higher boost. The S4 doesn't have that, so boost won't be higher.

 

OIC. Learn something new everyday.

The S5 engine also has lighter rotors and a different compression ratio than the S4. As far as swapping the engines in between the series 4 and 5 it just depends on the time you want to take. If i got a s5 motor for a good price I would do the work to put it in

 

Do you mean that there is less work to put an S5 TII into an S4TII? The reason for the swap is 240,000 miles on my original S4 engine and it's startng to blow blue smoke above 75mph. Also getting *real* hard to start after warm-up.

Anyway, it looks like this is a clean S5TII engine. I'm okay with the extra work (have the skills, etc). I really appreciate your opinion about getting enough advantage out of the S5 to justify that extra work.

- k -

 

With that many miles on the S4, I'd say it's definitely worth the work to swap in the S5. Do you have the S5 intake manifold as well? I believe it has a better VE than S4.

 

Yes, the engine is a complete long block...from a JDM importer

Thanks for the info.

- k -

 

Do you have smog check? Do they check for the EGR valve?

 

Yes & No. They test the exhaust, and have a look under the car with a mirror. I doubt these boneheads would know where to look for an EGR on an RX.

- k -

 

No, I was referring to just the turbo, not the whole engine. Note the lack of capitalisation...

That's very impressive mileage.

Since you already have the engine and you're comfortable with the work, then I think the S5 engine's improvements are worth it.

 

Thank you very much, NZ. I am preparing for engine arrival and will leave an update as i go.

 

You have an 87 T2 am I correct? If that's so, then this swap is a piece of cake. Just swap in the short block and keep all your s4 accessories. The only work intensive part that you would encounter would be changing the front cover and internals for the s4 T2 with mech. OMP. That is, if you want to do that instead of going premix.

I made the same mistake you did, a year ago. However I had no choice but to go standalone because:

1. The T2 shell was previously wired for a haltech
2. I needed to redo all the wiring since it was done poorly
3. I could not source s4 T2 parts quickly enough to make the conversion worthwhile

Good luck!

 

ive got a s5 into s4 n/a swap, not quite the same but kinda and yes it was worth it.

 

I just did an S5 RHD TII into an NA S4 LHD Chasis. Its probably about 6 times more work then swapping two different TII Series.