If you've ever done donuts (off-road, of course) or driven hard on gravel or dirt in an Evo X, you've probably gotten a warning light that cleared itself next time you started the car. This was probably caused by the accumulator running low and the pump not keeping up. The solution, offered by a few Europeans, is a larger accumulator on the pump.

Two (sets of) questions:

has anyone ever tried a larger accumulator? if so, did it do what you wanted?

has anyone who rallycrosses or rallies an X (with the OE system intact) had the warning come on mid-run or mid-stage? in other words, is there evidence that a larger accumulator would be useful?

 

I guess that I'll take the deafening silence as a pair of "no"s and move on with life.

 

Probably not because its not really a VIII/IX issue.

 

What about Rob? He rallies an Evox. He frequently posts on here, "Robevo" is his screen name, I believe. Shoot him a PM.

 

most get rid af ayc and use rs type plated rear diff so pump only works acd and has adequate pressure to accumulaator

 

Are you sure it's the accumulator and not an under performing electric motor? Easy way to test is to see if it will do a bleed easily.

I've had an electric motor 'almost' burn out on one race car, the solution was to replace the motor and at the same time change to the RS rear diff with a Ralliart Supertraction centre, add shafts, a diff mount and rear bracket and it starts getting expensive, but you can still use the GSR's pump, you'll just need to block off the lines.

 

First, the easy replies. Yes, I need to hear from people with Evo Xs that still have their AYC. The pumps in Evo 8s, 9s, and Xs are the same, but only the X (in the States) is trying to drive two clutches at the same time. Those with ACD only - and this includes anyone trying to obey FIA rules, such that their X no longer has AYC - can't tell me what I want to know.

As to the possibility that the pump is to blame, I agree. A pump that could keep up with both the ACD and AYC would not have this problem. In fact, a better pump would be a better solution than a larger accumulator, since a larger accumulator just delays when the problem will occur. Problem is, no-one makes a better pump. This is why the folks in Europe with 9s and Xs, running under non-FIA rules, so they still have AYC, seem to install larger accumulators.

But my question still stands: has anyone with an X (with the AYC still working) ever had the resettable warning in the middle of a stage or rallycross run? Is there any evidence that a larger accumulator (or better pump) would be worth a few hundred dollars?

 

No I never got any issue with a drive train. And I was running a small battery when I had an ayc. The cheap $60 one (deka)

 

Bingo. I should have just pm'd you, Rob. Thanks.

But I still wouldn't mind the $.02 from a rallycrosser, too.

 

I think the autocross should give a harder time on a drivetrain. Although it is a lot lesser usage in time. But they are using a lot wider and stickier tires and repeated ly alots of very strong turns on a very sticky surface. I am just guessing here on that. But I think autocross seems very hard on a drive train for me.

 

Hm. That's right. The tarmac setting uses much more pressure than Snow or Gravel (before you get the thing programmed to be actually useful). And it never went down when I autocrossed the thing, back when the pump was in good shape. Great point.

 

Necro posting!!!!!


Okay so apparently, after tracking my evo for a long time, i finally started getting the c161e & c161f every single session. I sent off my pump to get rebuilt by MLR and they just sent me a new one, as they said: "The pump block seems to have something restricting its flow. We believe it is either the check valve or filter that is damaged. Unfortunately, we have not been able to find a way to remove these components without damaging the pump.". My pump was factory warrantied around 40k miles (car as 60k now), so its basically a brand new oem pump that has only seen track miles. Slapped the new rebuilt pump on and guess what...... the same thing happened! Except it took longer for it to happen. Before it was happening 8-10 minutes into a session, now its happening after 10 minutes. I'm also running an additional 100 hp and have upgraded to 40 treadwear tires so the car is spending less time on straights, braking zones, and more time in corners. AYC has been removed forever so i'm not sure how it affects that.

Anyways, getting codes c161e and c161f again. MLR said the same thing iowa said, "We see this a lot with customers who track the vehicle often. The pressure in the system is fairly low, so when the clutches in the differential are activated on a consistent basis the pressure gets drawn down quickly causing the pump to turn on more often. We have quite a few rally customers in Europe and Africa who use a remote, adjustable accumulator. The accumulator is larger in size and has around the same back pressure as OEM. The backpressure on these accumulators can be adjusted if required with the use of nitrogen. If you're looking to track the vehicle often it's not a bad idea."

I'm already running an "upgraded" ACD pump (also relocated to trunk now) with the "upgraded" motor (i literally can't tell a difference in its operation or how quickly it increases pressure vs oem). This means i'm now looking to aftermarket accumulators. So far, no luck, but i'm just started my search.

It's been maybe a decade since i've been active on this forum. I just wanted to jump on to provide a record of my efforts, since i have yet to see anyone publicly post about this kind of journey

 

You could always put two OE accumulators on the same pump... however I am not sure that would help much. All the uprated race systems I saw used original accumulator and valve block with a much larger electric pump

 

Yea you post a lot on facebook. This is a hydraulic circuit. Nothing new here to figure out. If AYC is deleted then the fluid doesn't need to go there. Wasting current on pumping that fluid. Your Evo is only using ACD on track so if you are having problems maintaining pressure in the clutch pack maybe that should be inspected.