What is a decent HP on CIS w/SC cams and bolt-ons?

[flightlead404]

My '86 930 has RarlyL8 headers and dual outlet hooligan, TK long neck intercooler, SC cams, crank fire ignition with COPs, KKK 27/29 turbo, and a Tial wastegate with .8 bar spring, lightweight clutch package. Fuel head is unmodified.

I recently hit 365 hp on the dyno with AFRs right at 12:1 at 6,800 rpm.

Is 365hp a good number, or should I be able to do better than that?

[Mixed76]

2x factory crank HP, at the wheels, on .8 bar is pretty good.

[flightlead404]

Originally Posted by Mixed76

2x factory crank HP, at the wheels, on .8 bar is pretty good.

So stock at the flywheel is 280hp I think

Are you saying 560hp should be doable on CIS? Seems a bit unlikely to me, or am I misunderstanding what you're sayin?

I could go to 1 bar, or even use EBC to get a bit more midrange. I'm able to get AFRs into the 11's from 3,500 rpm but start to run out of fueling around 5,000 or so and the AFR starts to climb back up.

[Mixed76]

Sorry, I was thinking engine type 930, not 930 turbo vehicle. A naturally aspirated 930 makes 180-210 HP; doubling that at 0.8 bar within the stock rpm range starts getting to thermo limits. My comment was very much based on your boost pressure; fancier components at the same boost pressure will give marginal gains unless you increase the rpm.

I can't comment on potential results at higher boost levels; in my limited experience with water-cooled cars, ~1 bar is a sweet spot in terms of driveability, reliability, cost, efficiency, etc. For sure more power can be made, dunno where it starts to cost you (things breaking).

[1979-930]

https://forums.pelicanparts.com/911-930-turbo-super-charging-forum/521544-ultimate-930-dyno-thread.html

Some good info here on what has been done and dyno results. I still need to get to a dyno.
I know from zero to about 90mph I think the 79 930 will kick the 07 GT3RS's butt. That 8K Redline in the 07 will take over in 3rd.

[Mixed76]

All things equal, a 3.3 should make 10% more, so maybe 400ish is a practical limit, which is still pretty close to where your flywheel number should be. So I don't think you're leaving much on the table, which I think is what you're asking.

Sent from my Nokia 7.1 using Tapatalk

[flightlead404]

Originally Posted by Mixed76

Sorry, I was thinking engine type 930, not 930 turbo vehicle. A naturally aspirated 930 makes 180-210 HP; doubling that at 0.8 bar within the stock rpm range starts getting to thermo limits. My comment was very much based on your boost pressure; fancier components at the same boost pressure will give marginal gains unless you increase the rpm.

I can't comment on potential results at higher boost levels; in my limited experience with water-cooled cars, ~1 bar is a sweet spot in terms of driveability, reliability, cost, efficiency, etc. For sure more power can be made, dunno where it starts to cost you (things breaking).

ok, yeah I'm trying to get a sanity check and see what else I might be able to do before I start doing things like:

-Full EFI conversion
-Bigger P's and C's
-Higher compression P's
-Porting/flowing heads

My guess is I'm approaching or even at the limit with CIS. Maybe I could eke out a little bit more by doing fuel head work to get a bit more fuel flow, which would in turn let me raise boost pressures. But, I'm guessing I'd still be under 400hp. I could ditch the CIS completely and go with a full EFI conversion, maybe that would get me 400 or possibly a shade over. I'm not really sure what is doable without cylinder and head work.

[gumba]

Is this crank h.p. Or at the wheels?

[Mixed76]

Your dyno shows a nice match between cam, turbo, and port sizes. You may be able to extend the powerband to slightly higher rpm with more fueling.

Sent from my Nokia 7.1 using Tapatalk

[flightlead404]

Originally Posted by gumba

Is this crank h.p. Or at the wheels?

At the wheels. Mustang dyno

[flightlead404]

Originally Posted by Mixed76

Your dyno shows a nice match between cam, turbo, and port sizes. You may be able to extend the powerband to slightly higher rpm with more fueling.

Sent from my Nokia 7.1 using Tapatalk

That's what I was thinking too. I've pretty much hit the limit on what the fuel head can deliver.

[TurboKraft]

Originally Posted by flightlead404

My '86 930 has RarlyL8 headers and dual outlet hooligan, TK long neck intercooler, SC cams, crank fire ignition with COPs, KKK 27/29 turbo, and a Tial wastegate with .8 bar spring, lightweight clutch package. Fuel head is unmodified.

I recently hit 365 hp on the dyno with AFRs right at 12:1 at 6,800 rpm.

Is 365hp a good number, or should I be able to do better than that?

That is good, for 0.8bar boost. Pretty typical from what we've seen on the Dynapack chassis dyno.

Originally Posted by flightlead404

So stock at the flywheel is 280hp I think
I could go to 1 bar, or even use EBC to get a bit more midrange. I'm able to get AFRs into the 11's from 3,500 rpm but start to run out of fueling around 5,000 or so and the AFR starts to climb back up.

Yes, factory all-stock USA-spec is 282hp flywheel, and 240-250whp is about typical.

A few things stand out:
1. It's pointless to rev the engine past 5600-5800ish where it makes peak HP. Sure, the revs sound good, but you're usually faster if you just use the next gear and the torque.
2. You could add a little more boost, which will lean out the mixture some if you're near the limit of the fuel delivery. At 5800 you're roughly 11.7:1 AFR, and you would be fine at 12.0-12.2 on that 93-octane gasoline.
3. If you can lean out the mixture from 3400-up so you're not into the 11s AFR, you should gain a bit more torque. You could do this by removing fuel or adding airflow (boost).

You're running the Microsqirt-controlled CIS, right?
If so, how adjustable is that turning out to be?
And is there a spare programmable channel available for you to implement 3D boost?

[flightlead404]

Originally Posted by TurboKraft

That is good, for 0.8bar boost. Pretty typical from what we've seen on the Dynapack chassis dyno.



Yes, factory all-stock USA-spec is 282hp flywheel, and 240-250whp is about typical.

A few things stand out:
1. It's pointless to rev the engine past 5600-5800ish where it makes peak HP. Sure, the revs sound good, but you're usually faster if you just use the next gear and the torque.
2. You could add a little more boost, which will lean out the mixture some if you're near the limit of the fuel delivery. At 5800 you're roughly 11.7:1 AFR, and you would be fine at 12.0-12.2 on that 93-octane gasoline.
3. If you can lean out the mixture from 3400-up so you're not into the 11s AFR, you should gain a bit more torque. You could do this by removing fuel or adding airflow (boost).

You're running the Microsqirt-controlled CIS, right?
If so, how adjustable is that turning out to be?
And is there a spare programmable channel available for you to implement 3D boost?

#1 - Agreed
#2 - I was thinking of either going to a 1.0 bar spring or a manual BC, or have microsquirt control an EBC valve which was the original plan
#3 - We did try and lean it out a bit there, but then we got an odd bump in the curve higher up, wasn't able to smooth it out

Yes this is the FrankenCIS (microsquirt) controlling both eWUR and lambda valve. In addition to controlling fuel I have the 'squirt also controlling ignition with Denso COPs. Seems to work rather well.

I would say +/- 20% was about the max change we could make with both eWUR and lambda. And +20% is running into the limits of the fuel head.

I need to look back into it, but the way EBC works in the microsquirt/tuner studio it is based on throttle position, so I'd at least need to add a proper TPS. My thinking now is that is unnecessary and a manual boost controller is probably enough.

I have another odd problem I need to fix first - as the car gets hot my AFR starts to read leaner and leaner. On a hot day I can just let it idle for 30 mins and watch the AFR go from 13.5 to off the scale lean with no change in idle speed or sound or smoothness. I suspect a heat soak issue with where I have the controller.

[RarlyL8]

CIS 930 performance packages are RarlyL8's wheelhouse. Our tuned headers, muffler, Intercooler, K27-7200 and SC cams yield 360whp at stock boost level. Swap out or modify the turbo, add modified or Euro fuel distributor and adjustable WUR and you are at 400whp. You can get above that number with CIS by porting the heads, bigger cams, more boost and ignition control, then adjusting the modified fuel distributor. You don't say which version of K27/K29 turbo you have but it should support 400whp with 1.0bar boost.

[gsxrken]

Flightlead those are great numbers and at safe AFRs. You have done a great job sorting your combination- I can only imagine the hours and intel you had to invest in to get there.

Years ago, and I mean like late 90s or the earliest 2000’s, there was guy on Rennlist Brent930 that IIRC got 430HP out his CIS. I’m sure he was beyond .8bar for that, and I don’t know how long it held together either. But he was way ahead of the adjustable WUR and fuel head tweaks... someone could correct me but I think he actually innovated on the fuel head mods. No idea of his background but he was a groundbreaker for us garage chumps.
I’m sure CIS 430HP has been eclipsed but I don’t recall seeing by whom.

[RarlyL8]

There is a "practical" limit of ~430whp with CIS if you confine yourself to basic fuel distributor/WUR mods and adjustments. Beyond that gets expensive and time consuming. With advanced mods based on the OE 930 CIS 550+whp is achievable. Big HP CIS engines have always been around, most were vintage racing or tribute builds.

[flightlead404]

Originally Posted by RarlyL8

CIS 930 performance packages are RarlyL8's wheelhouse. Our tuned headers, muffler, Intercooler, K27-7200 and SC cams yield 360whp at stock boost level. Swap out or modify the turbo, add modified or Euro fuel distributor and adjustable WUR and you are at 400whp. You can get above that number with CIS by porting the heads, bigger cams, more boost and ignition control, then adjusting the modified fuel distributor. You don't say which version of K27/K29 turbo you have but it should support 400whp with 1.0bar boost.

Yep, have all that. Turbo is yours as are headers and exhaust. FrankenCIS instead of adjustable WUR and RPM pill Rube Goldberg contraption also gives me ignition control.

My next step is to swap wastegate springs I think.

[flightlead404]

Originally Posted by gsxrken

Flightlead those are great numbers and at safe AFRs. You have done a great job sorting your combination- I can only imagine the hours and intel you had to invest in to get there.

Its been about a 2 year project, and I've learned a lot. Along the way I took the opportunity to do a bunch of other general maint things like resealing etc.

I could duplicate it in a long weekend

[slyguy]

Ha you'll never go back to the .8... make sure your rev limiter is turned on

[flightlead404]

Originally Posted by slyguy

Ha you'll never go back to the .8... make sure your rev limiter is turned on

Ah and now, with the MS controlling the ignition, I have a nice soft rev limiter that just progressively pulls timing