Michael Robertson

Hey Guys,

I recently purchased a set of Authothority Stage II chips for my 88 951 S.

The part number on the chips is below:

DME: POR.01.951.320.DME
KLR: POR.01.951.320.KLR

The installation went smooth enough so I thought I woudl test it out..

On a road test with the new chips and the LBE (original banjo bolt) I noticed a sort of surging forward at 3/4 to half throttle (5 -6k RPM) where the car felt like it was being held back... or surging..

I ran the tank down to reserve in my testing and was impressed with the speed of the car. I just filled the car up with Shell Optimax (98 Octane) and now when I drive the car, it just cuts out..

I put my foot to the floor and there is no response.. and then it will movea bit but it feels like there is on fuel fuel in the engine.

I'm thinking I have 2 problems:

1 - Surging at high RPMS -

Could be because LBE set to to factory 12 PSI, and Stage II Chips shooting 14.7 PSI +.. I think the LBE might be sort of 'throttling' the boost and thus causing the car to surge.

Thoughts guys?

2. - My Fuel pressure regulator, or fuel pump or something like that is shot and causing the car to die while I am driving normally as no fuel can get to the engine when it most needs it and it just happened to die..

I'm not sure really about anything.. I'd like your advice.. Should I change the LBE to pass the boost at about 15PSI on the wastegate or leave it as stock?

Or is the fuel issue causing the surge at high revs, like 5 or 6 grand..

I know you guys have experienced this sort of thing before so I'd be interested in hearing your opinions.

Help please - If it's fuel, what products do you reccomend to resolve the issue..?



Michael Robertson

88 951 S
Authothority Stage II Chips
LBE
Cat Back Exhaust
K and N Filter.

Toolmaster

Hey Mike -

You said that you still have the original factory banjo bolt in the car? But you also have the LBE in the mix, and Autothority stage II chips.'

Here's what it sounds like...

At any RPM level, the APE chips are "expecting" a boost level that the LBE changes to something else. Chances are you're getting "more boost" than the chips are expecting, which is resulting in a lean condition (which is DANGEROUS here). the APE chips were designed to work with the jetted banjo bolt, meaning that they expect the wastegate to open sooner rather than later as in your situation.

You've changed the fuel curve within the DME, but haven't changed the boost curve to coincide with the new fuel curve.

To test this out, I'd remove the LBE and install the APE jetted banjo bolt. Drive the car then - and see what happens. Chances are your issue will go away.

According to the Lindey Racing site, you should set the LBE to about 5 psi less than your full boost setting which will allow the wastegate time to respond. If you're set at 12 on the LBE, try going to 9ish psi which would set the boost at about 14-15psi total. (This of course assumes that the APE chips are mapped for 14.7psi - or 1 bar of boost. ) Please insure to use the factory banjo bolt though when you reinstall the LBE...

HTH!

Jay
86 951

Danno

Michael, what you're experiencing is perfectly normal for Stg.2 AutoThority chips! They dial in a LOT of ignition retard and extra fuel, hence the sluggishness. It's made especially worse because you're running less boost than the chips were programmed for, making your mixture entirely way too rich!

To fix this, adjust the LBE to give you about 15psi of boost. Then slowly and gradually do several runs with increasing throttle making sure your boost stays within limits and the car operates smoothly.

krickmann

"New Guy" alert!!

Michael Robertson

Thanks Guys..

I've got 2 answers - one to open up the LBE, and one to tighten it down more.. Seeing as Danno has the guru next to his name I will go with his reccomendation..

The car started fine this morning and I let it idle until it warmed up but I could smell that it was running waaay rich.. (even at idle)..

It idled for about 2 minutues.. and then sort of shuddered a bit and continued idlign.. By the smell coming out of the exhaust I could tell that it had richened itself signifigantly.

My question is, how much does the LBE affect the actual idling of the car with AP Stage II Chips?

I will set the LBE to 15PSI though and let you know of the results..

Thanks A bunch guys.

Michael

Danno

"My question is, how much does the LBE affect the actual idling of the car with AP Stage II Chips?"

The LBE should do nothing to affect idle since there's no boost developing. Not enough pressure to get past LBE, and wastegate stays shut. Idle mixture is only determined by chip-mapping, fuel-injector size and fuel-pressure.

If you have an adjustable fuel-pressure regulator, it would be a good idea to turn down the pressure a little.

Michael Robertson

Danno,

Thanks Mate... I didn't think the LBE would affect it at idle but just wanted to be sure.

Thanks for letting me know that the chips make it run MUCH richer.. I let the car idle in my garage and the black stuff that ended up on the floor of my garage from the exhaust was amazing..

So just to get it straight.. I need to adjust the LBE to go for around 15 PSI in order to get rid of the surging on full boost..

How much more fuel do you think it will use, off idle, around town?

Thanks a bunch Danno.. I'll buy you a beer if you're ever in Melbourne

Cheers,

Michael

krickmann

Michael,
I own an'86 951 with 63,000 miles and similar modifications(Autothority chips with supplied jetted banjo bolt, LBE,993 BOV,K&N filter replacement) which I just recently sorted out.
When I installed the Autothority chips, I also installed the banjo bolt that was included with the kit. "This bolt modifies the signal sent to the computer operated cycling valve and allows it work in a higher range of boost (0.25 - 1.20 bar). The software (E-prom) then controls the boost to a maximum of approximately 0.95 bar (1.95 indicated) of boost" (Quoted from the APE Installation Instructions)
I utilize my LBE only to spool the turbo up quicker at low engine RPMs. (By canceling the opening signal pressure to the wastegate at low boost conditions, the LBE maximizes the spooling effect of the exhaust gas pressure.) I don't have my LBE set high enough where it can interfere with the E-prom regulating the maximum boost pressure.
My vehicle experienced loss of power, surging and trailing black smoke above 4000 rpm after I installed the Autothority chips and banjo bolt simultaneously with the LBE . After first taking the LBE out of the loop and eliminating its' possible effects, I chatted with a very helpful engineer at Autothority who stated that it did not sound like a DME/KLR issue. I then started checking for leaks in the intake system and sure enough the hose clamp on the compressed air outlet of the turbocharger was improperly installed, allowing air to escape when the "new" higher boost levels were at their greatest!
I did not have the rich idle problems you are experiencing, but I would suggest that you first check all your connections carefully. It's simple and takes very little time. Then install your APE supplied jetted banjo bolt without the LBE and see if the car runs properly. When you have that set up working, add your LBE to get the turbo to spool up quicker.
Which cat back exhaust did you choose?
Good luck!

Danno

Just a quick clarification on the APE Stg.2 chipset as well as the LBE. These two are independent of each other and manages different areas of the car's performance.

First, the chipset. Part of the issue with the stock 951 configuration is that the KLR chip is programmed to roll on boost gently and roll it off at high RPMs. Whether AutoThority reprograms this behavior or not is debatable. No chip manufacturer has ever been able to re-program the KLR to yield higher boost. That's partly because there's no feedback operation with the cycling-valve in managing boost, just a fixed duty-cycle vs RPM & load maps. If you try to reprogram these maps, you would get 0.9bar with some cars, while others will get 1.2bar or more with the same KLR chip! Why? Because the wastegate spring will be in different stages of wear in everyone's wastegate. Some will only require 3-4psi of pressure at the inlet nipple to open, while others with strong-as-stock springs will require 8psi to open. That's why AutoThority includes 3 difference size jets to install in their Stg.2 chips; allowing you to choose one that gives 15psi of boost with your particular car.

Once you are able to develop 15psi of boost, the DME chip then has reprogrammed fuel maps to ensure that you have adequate fuel for your increased flow. However, under full-throttle/high-RPM operation, O2-sensor feedback is ignored. Thus the importance of proper matching of the fuel-map to actual air flows.

The LBE on the other hand, is a check-valve pressure controller. It blocks ALL pressure signals from reaching the wastegate diaphram until a set pre-defined pressure has been reached. As such, it takes precedence over the banjo bolt. It doesn't matter if you have the 125, or 145 jet inside your banjo bolt, NONE of that pressure's getting through unless the LBE allows it. As such, the LBE allows faster boost build-up (combats stock smooth roll-on of boost). And it'll hold boost longer in the upper RPM ranges. If you have your LBE set so low that it allows pressure through early enough for the banjo-bolt to function, you've defeated all the benefits of the LBE.

Regardless, neither the banjo-bolt of LBE has any bearing on idle since there's no pressure in the intercooler line going to the wastegate. This is simply a fixed fuel-map function.

In Michael's case, he shows signs of richness at both idle and under normal operations. A systemic across-the-board richness under all conditions. I would inspect your fuel system for either a bad fuel-pressure dampener or FPR. Also make sure that you DON'T have the S2 3-bar regulator. This can only be used if you have some way of fine-tuning the air-flow signal, like with the ARC2 unit.

michael2e

I took a run up to Tampa for some T&A in my similarly equipped 88 951 (with LBE) this past weekend. After running perfectly all the way up, on the way back after doing some aggressive passing (you know what I mean) I realized rather acutely that my car developed a noticeable hesitation at higher RPMs(over 4000) while boosting and that the car felt very sluggish kind of like you described. I could do a slow acceleration or drive steady at highway speeds fine but when I tried to go for it the car bogged. My first thought was a fuel problem and as I slowed to check it all out the engine felt like it would kill as the idle was way off. By keeping a little throttle open I managed to keep the car running so I could get to a safe place. It would actually idle fine this way above about 1500 RPM. OtherwiseS she was runnin way rougher than the chick I had gone to see when off the throttle.

So under the hood interestingly enough the outlet hose from the turbo had blown off the intercooler pipe (probably during one of the hi-speed full boost passes) just enough such that I suspect it caused an alteration in the A/F ratio resulting in the bogging at high RPM/boost and the poor idling but yet was still connected enough such that at normal operating RPMs it was able to allow adequate airflow.

Anyway, it was nice to have such an easy remedy in the middle of the Everglades! Ran beautifully again after the 30 second fix right up to 120 MPH.

So as Krickman advised you certainly could have a leak in the intake path that may only appear on boost. Cheers,

Mike <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

Michael Robertson

Thank you so much everyone!

Your problem Michael2e is exactly the same as mine had.. the car just died for no apparent reason when I was coming home from a restuarant..

I rolled it down hill and feathered the throttle and made it home safe, but even driving in the driveway to the garage it died on me..

It started fine the next morning and idled way rich, black stuff on the garage floor..

I'll get my mechanic ( my dad :-)) to check over for blown hoses though, and then set the LBE to 15 PSI..

And then we should be sweet hey..

So now I owe all of you guys a beer.. <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />

Cheers,

Michael

bron964

[quote]Then install your APE supplied jetted banjo bolt without the LBE and see if the car runs properly. When you have that set up working, add your LBE to get the turbo to spool up quicker.<hr></blockquote>

make sure that when you do install the LBE that you remove the jetted banjo bolt supplied with your APE chips and reinstall the factory bolt...

from Lindsey: "We highly recommend that if you have the “Banjo bolt” with the air restrictor, remove it and install the factory bolt! The reason for this is that once the Boost Enhancer opens, you need to get the boost to the waste gate as soon as possible. There is no more reason to delay it any longer!"

just wanted to make this clear... <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

krickmann

So it sounds like I'm not getting full utilization from my LBE if I'm only using it to spool the turbo up faster at low RPMs.
Am I to understand that I should reinstall the factory non-jetted banjo bolt, start with the LBE set to about 10psi, and tune it to achieve no more than 2.0 bar indicated at any rpm under full throttle?

Danno

Yup, that would give you the best performance with the combination of parts you have. The banjo bolt with smaller jets is a restrictor that limits the flow of air down towards the CV & wastegate. It really just delays the pressure build-up, not what that pressure ultimately builds up to. So the result is that you may have higher initial boost, but it will eventually bleed off to stock levels after 5-6 seconds. The LBE on the other hand, prevents any pressure from getting past at all.

adrial

Hey michael R..
Considering I sold you the chips I figured I'd respond.

After removing the APE chips and jet in the banjo bolt, gas mileage stayed pretty much the same...increased by maybe 2mpg? On 1 tank of gas, mostly highway (70-90mph+)+ 6 runs @ the autocross, I got 21mpg.
Prior to removing the chips I got 19-20mpg.

Anyway, just chips and stock boost the car didn't smell rich and pulled throughout the range...no hesitation.

Now, no chips and stock boost the car seems to run pretty much the same as chips and stock boost.

SO, if you're getting black smoke at idle then something's up with your car unfortuantely. Aside from checking for air leaks as others suggested, I would also throw a fuel pressure gauge on it...

Good luck...and yes do crank up the boost to 15psi. I highly recommend an aftermarket boost gauge for doing this...the stock gauge will just hit the stop at 2 bar and you'll have no idea just how much more than 1 bar boost (2 bar gauge) you're making...