951Roadrunner

I think i am short on knowledge here. My stock 1986 951 has dme and klr boxes. The rogue system has a chip fir the dme box and adds a boost sensor right? So what parameters are being measured? What does the klr box do in stock situatiin and in the a-tune situation?
I am in podunk albuquerque nm and i am NOT a mechanic.
I have a porche certified mechanic suggesting that my first modification should be to put in the 944 n/a cam in to make the 951 breath better. Then, do chip set such as those for dme and klr such as from LR. This apprach seems contrary to what others on RL have spoken of.
I dont have nearly the knowledge to intelligently debate this with a certified porsche mechanic.
Any help would be appreciated!!!

Rogue_Ant

The KLR's primary function is to listen for engine knock, and if it hears knock, it will pull out ignition timing to help reduce knock.
The KLR's secondary function is to control boost pressure via the cycling valve (CV).

Yes, the A-Tune adds a pressure sensor. So we measure everything that the factory does (airflow, coolant temp, air temp, ect) and now we measure boost pressure too.

The KLR functionality does not change with the A-Tune. It is a good system for listening to the engine and determining knock. The reason we do not typically supply a KLR chip is that all KLR chips only served to increase boost pressure... Most of the time, people use a manual or electronic boost controller, bypassing that part of the KLR's functionality - rendering a non-stock KLR chip pointless.

White_951

First of all, I think your mechanic has offered some sound advice, although I would also add the LR 3" exhaust...

I'd go with the full M tune from Rogue and get rid of that 26 year old barn door technology, couple that with the LR hydraulic Webcam 274 and the 3" exhaust setup....

You won't break any land speed records with your 26/6, but you'll get where your going in a hurry...

cheapmods

Meaning you could run higher boost on completely stock car with no aftermarket chip? Is the A-Tune like a purchasing an aftermarket chip that automatically adjusts to future mods?

Rogue_Ant

Check out here for more info on the A-Tune:

http://www.roguetuning.com/951_afm_kit_a-tune%C2%A9

Crackership

Is the NA cam an actual improvement on a 951? I would think that an NA cam would have too much overlap for forced induction...

hot-J

Here is my 2 cents on the A tune. I installed it with a new cap and rotor, new plugs, fresh timing belt and speed and ref sensors, lightened flywheel, 3.0 FPR, cat delete, drop in k&n, tial 46mm Wastegate, MBC, and Sakiou Michi catch can all at the same time. @ 15 psi I was a bit underwhelmed. Scared to turn up the boost..... I gradually increased to 19psi. @ 19 the car is a rocket for the mild mods it has. I would also like to note, I have another car with a Vitesse stage 3 kit, and running 93, I can not push the boost past 17 psi without blowing a HG. I have had the A tune up to 21 psi, but at about 20 the stock turbo gives up. This alone makes the A tune well worth it. Assuming your internal motor is in good shape.

hot-J

I would also like to add, an N/A cam will be the next mod for the above setup. I had an N/A cam on my Vitesse stg 3 setup befroe going with a milledge cam.... and it was awesome.

Adker

I read the boost was limited to 18PSI. Special chips?

blown 944

NA cam doesn't have any overlap, just a little more exhaust duration and a little more lift. Iirc

eman930

I thought M-Tune had no psi limit? You can run whatever your full mods support for the most part

Paulyy

It does have a psi limit. He usually sets it to ~18 psi. mine is roughly ~18.5 psi
E85 is ~25 on mine

Rogue_Ant

NA cam has 2° overlap... so pretty much nothing.

Everything has a psi limit

The system can read up to ~30psi, but usually we want the overboost protection at a more reasonable threshold...

refresh951

Bit OT but...

After I installed my stroker motor and had a good bit of miles on it, my best friend came over and wanted to drive the 951. I told him I just installed an EBC and it was not working right so do not get on it as I have no boost control. He agrees and we go for a drive. He comes around a corner and floors it in third gear. Tires break loose, car goes sideways, thrown back in the seat, then boost limit hits, very violent power cut, we are thrown forward. Alarm went off on EBC, captured peak: 32 PSI. I chalked it up as lesson learned. Car was fine. Yes, there is a limit.

Rogue_Ant

Yes, the overboost isn't instantaneous... the software allows a very short overboost time before cutting in. This is to keep it from being overly sensitive.