RarlyL8

I currently am using a K27-7200 that was purchased from iA years ago when they first came out. Turbo technology keeps improving and the 7200 may no longer be the best turbo for my application.
Is the 7200HF a significant improvement (for me) and can I have my 7200 modified to HF spec? What change will I see?
Here are the particulars:
930 3.3L, 1978
Euro exhaust
Euro CIS
SC cams
0.75bar spring
B&B intercooler
Stock heads
ARP rod bolts and head studs
Wastegate dump pipe
915 trans (VERY quick through the gears to 7000rpm)
No dyno sheets, runs 90mph in the 1/8 mile.

cobalt

I can say that i switched from the Stock 7200 to the HF turbo and I found a vast improvement in the way the car responded. Much more throttle control and much better top end.

I don't believe they still make the HF I believe it is now either the HFS or some other variant. I would talk to Stephen or Kevin and get their opinion.

Kevin

The HyFlow is still in production. Rarly, email me, I'll give you some options.

cobalt

Kevin,

What are the actual differences between the different models?

Kevin

The main difference between the HyFlow and HyFlow "S" is the compressor housing inlet. The "S" has a 3" inlet.

Tripster

Get you a big turbo (HF, KS, SS, PDQ or something and lets go race, im getting bored' and need some excitement. Ive got a white Turbo sitting in the parking lot "with Hair standing up on the whail Tail in a frenzy wanting to race.
Did not mean to Hi-jack this post, please continue with the regularly scheduled program.

PorschePhD

Chuck Jones

What's the main difference between the K27 7200 and the Hi-Flo? How much more do you get out of the hi flo if you don't intend to track....is the difference worth it?

Kevin

There has been many threads about the Hyflow.. The stock 7200 runs out of air at around 5,100-5,250. The ability of the compressor wheel to generate boost efficiently drops. The Hyflow will continue to produce boost to redline, efficiently. When you have a higher efficient compressor stage, you will produce less heat and reduce the thermal load on your IC..

RarlyL8

OK Tripster, it's go time!
All I have to do is lay back and be ready to dodge the shrapnel when your 915 explodes. That's my strategy and I'm sticking to it.

As for the HF, my question is - will I see significant improvement IN MY APPLICATION?
Because I use a 915 the gears become very short due to the power the engine lays down. Things happen so fast that it is easy to rev past 7000rpm. The HF would likely help me in 4th and 5th gears but would it hurt me in 2nd and 3rd? Does the HF produce more HP than the 7200 or does it simply have a broader HP band?

PorschePhD

Yes. Bottom line is it will add HP and increase the powerband. Saying it will not make power ina 915 is saying it wouldn't make power in a G50 either. I have one on my 930 and my car is a G50 and I make more power than your car and still find it is useable over the 7200.

RarlyL8

Thanks for the replies.
As odd as this is going to sound, I am not looking for more power. A more broad power band would benefit me in 4th and 5th gears but a raised power (or torque) level will grenade my already stressed 915.
How about down low? Right now all boost is in at 3000rpm. Will an HF come on sooner?

Kevin

What exhaust system are you running?

RarlyL8

Euro exhaust with a dump tube on the wategate and a stock neighbor friendly muffler.

Tom F

I have a similar setup in my 3.0 turbo, with a standard K27-7200. I don't have a perfect basis for comparison, because I changed to the Euro exhaust at the same time that I changed from the 3LDZ to the K27 and because my 3LDZ was worn, but the difference in low end performance, i.e., feeling of a broader torque curve, is remarkable. If I were doing it again, I would go with the hi-flow, but I got a sweet deal on the new K27 from the shop where I shipped my 3LDZ for rebuilding, after UPS lost my package.

The only wrinkle, I feel, is that the ignition advance curve, and the warm up regulator boost enrichment (I have a later WUR, the one for the Euro 3.3) are mismatched to the K27 - the increased boost at low rpm should be compensated by slower enrichment and a little slower advance, is my seat-of-the-pants impression. My gas mileage is awful - around 13 mpg. This could be the SC cams, too, I guess.