Bster13

iTrader: (2)

Ok, so I'll fess up... I sold the EVO awhile ago and purchased a Mini Cooper S to better fit my life. I'm coming here because there is a world of knowledge about turbos in general, so hopefully y'all won't beat me up too bad for moving on.

(If there is a better forum for this, please feel free to move it along mods, but I though this would apply for any turboed car, including the EVO)

After reading some piston failure threads I'm trying to walk the line and make good/safe power. What would increase heat inside the engine more and what drive characteristics would there be?

Stock Mini Cooper S Turbo:
- Tune it to run upwards of 20PSI. With the smaller turbo, it has to work harder and increases intake temperatures because it is perhaps out of its efficiency range, perhaps more back pressure, and thus heating the air up more and thus more heat in the cylinders....heat bad.

JCW Turbo (slightly larger) on Mini Cooper S:
- Tune it to run say 18-19PSI. With larger turbo, it has to work less to flow the same CFMs into the cylinders, thus less heat into the cylinders for the same amount of CFMs.
-Potential downside would be later spool, though I'm not sure how much later.

Am I thinking about this correctly? That at the cost of a little later spool, I could use the JCW turbo as a means to pump less heat into the engine and get close to the same HP/TQ figures and same area under the curve?
*assuming all other bolt-ons are done, including intercooler. No meth for me at this time, but a consideration.*

This was a good read:
10 psi on a big turbo and small turbo-How come one makes more power?!? : KA24E / KA24DE Forum

Many thanks for any help the EvolutionM folks can lend. Thx.

Leonthefaded

I will admit that I chuckled when you said you sold your evo and bought a mini cooper.
Never the less. I think you're going in the right direction. Pushing the stock turbo to its limits is just a bad idea in my opinion. I say that from an old 98 GST I had with the stock T25 turbocharger; I pushed it too and beyond its limits on a DD and the result was pretty crap. The turbo had play I never seen before.

I admit I do not know much about mini coopers - but, if it was my mini cooper I would just upgrade the turbo, tune to stock boost levels. I'm sure there are other ways to reduce the "turbo lag" that you would get. But this is all just off the top of my head and an opinion.

Bster13

iTrader: (2)

I understand the chuckle, I miss the EVO at times for the performance, but I got tired of the younger EVO folks just wanting to do roll-ons in the middle of the night.

I ended up selling the EVO because it didn't give me the same feeling as my motorcycle (I will never ride again) and purchasing a Brunton Super Stalker:
https://www.facebook.com/media/set/?...1&l=27019aa756

While that was AMAZING for me, the new GF (and now Wife) at the time was not keen on getting in the car much and taking trips, go figure? Haha.

So now circling back to something fun, but has a better social scene where folks get together as well as do some HPDEs and backroads trips that I enjoy more than the roll-on stuff.

Anyway, thanks for advice on the turbo sizing, still got some figuring to do.

Leonthefaded

No problem. I miss my bike too. 05 CBR600

killerpenguin21

iTrader: (20)

dont worry bryce, your old evo is living a great life!

big turbo at low boost is better all day (well to a point)

Bster13

iTrader: (2)

I'm glad it's treating you well. I'm sure you're pushing it more than I. Now I'll push the little MINI a bit.

adriano_917

iTrader: (14)

You will see some power increase as the S has a little more compression than the JCW but you want a bigger turbo with less psi to make the same power as a smaller turbo ? As spool goes youre not even going to feel the difference but get the JCW exhaust manifold too.