Damien Cort

How come none of you run EBCs? I'm sure some do, but by and large all I see are MBCs. Is it that they aren't compatible with the 951? I would think having that much control over boost be preferable to an MBC. Thoughts?

Perry 951

Price is the big one. A good EBC is about $300. A good MBC closer to $50.

I have had no problems with mine. I like it and think it works as good as an EBC for what I need it for. (Set it and forget it type of thing.)

Damien Cort

Wouldn't it be much more preferable to be able to punch up the boost on the fly? Not to mention the lack of stress on the engine, when you're just driving around town at low boost. Is this just not a thing?

ninefiveone

Here's my take on it...

First and foremost, an EBC would be great for creating more power under the curve. i.e. have the boost come on sooner, drop off slower or not at all. Gear based boost control would be great for getting off better launches (less wheelspin).

But I don't see a need to ever punch up a different boost level on the fly. I suppose it could be handy to have a lower boost level setting for rainy/slippery weather but I could just as easily not drive as hard. It seems a lot of these motors live long lives and the ones the go bad are a result of detonation, not stress from being a turbo motor.

-Hugh
'86 951

Danno

Adjustable boost is a pretty big mis-understanding. For any and every boost-level, there is but one optimal fuel and ignition curve. It's hard enough to control one variable (boost) so that you can dial in fuel & spark to optimize power at that boost level. Really only way to optimize this is with custom chips and dyno tuning (or using a complete replacement EFI systen like SDS, TEC-II/III, Motec, etc).

When you finally have fuel & spark dialed in optimially, any other boost level is a compromise; you aren't making maximum power possible, unless you have aftermarket EFI that can alter fuel&spark to match new boost level.

Actually, if you have things dialed in to say.... 15psi of boost, you can't even run higher boost like 18psi, because your fuel will be too lean and spark too advanced; you'll get knock for sure. However, if you set your car up for 18psi of boost, you aren't making optimal power at 15psi either. It'll be too rich with ignition too retarded.

So don't bother with adjustable boost. Set it to the maximum you can safely use and tune your fuel & spark for that boost level. Then just use the accelerator pedal to adjust how much power you want to lay down. If you're just trolling around town and want to take stress off yor engine, just don't give it as much throttle.

ninefiveone

Danno's comments lead me to the question that's been bouncing around in my head...

If you have an AVCR which can manage boost better than the stock CV, it also changes the boost curve. I assume you'd need a fuel controller to adjust for that. What's the best fuel controller to use? Any reason to jump on the ARC2 bandwagon or is it worth looking into an Apexi AFC? I understand that standalone engine management would be the best way to do this but I'm on a budget.

Hugh
'86 951

Russ Murphy

Hugh,
If you purchase those two Apexi units you'll have spent 90% of what the SDS engine management system costs complete!

ninefiveone

90% of what an SDS kit costs complete...but noone has yet to tell me what additional costs I'll incur installing it. BTW...what's the cost of the SDS kit? Better yet, how much to get the whole thing up and running?

I kid you not, if it's reasonable, I'll go down that road.

-Hugh

Rob

You still need some form of boost control. The SDS does not have that capabillity from what I've read.

Rob

*eurospeed951*

I thought the avc-r could controle fuel as well as boost?

Russ Murphy

The SDS EM-3E for multispark(MSD) with stock distributor with all the goodies for our cars (3 bar MAP sensor,A/F meter) complete w/harness is $1128.00 plus shipping. I'm spending about another $150.00 for intake and crankcase ventilation stuff. I'm probably going to use the turboxs hi-performance manual boost controller (essentially a LBE poppet-style valvecombined with a bleed valve controller)- $129.00. I'm going to let my right foot control boost level.

Rob

The avc-r only controls boost. APEXi makes the s-afc to modify the air-flow meter signal to optimize to fuel-air ratio.

Rob

SamGrant951

Yes, so can APEXi's Fuel controller work with our cars like the ARC2 does?
Just a question..Im not interested in Stand Alone Engine Management at this time.
It would be nice to be able to get the Modern Performance MAF for 550.00 and then a fuel controller like the ARC2 or APEXi's to work with it w/out spending 1500.00 for a complete MAF.

Just a thought...

Danno

I say go with the A'pexi Super AFC then. It has way better tuning control and resolution compared to the ARC2. Not to mention it has data-logging features to really help you fine-tune your system.

They also have some nice IHI turbos and wastegates too.

Rob

Danno,

I didn't think the super afc could convert the maf input to a afm output like the arc-2 does. I thought that the afm is essentially a potentiometer while the maf generates a variable voltage.

Rob