promax_motorsport

Hi,

Will be fine with Vitesse chips if you are replacing the AFM.

Regards,
Andrew
ww.promaxmotorsport.com

tommye

Great news !!!
At last someone who seems to have figured out how to correctly modify boost control - by acting directly on the original system....
The KLR + the CV are used to control boost level and boost roll-on behaviour. Factory programming means slow boost roll-on and need for flooring the pedal before things start to happen. Obviously the right way to modify things is to reprogram the KLR.....
Both roll-on behaviour AND boost level can be controlled by simple re-programming !
At last we can get rid of these stupid brightly coloured devices we use to "control" boost....
Andrew, is it really that difficult to reprogram the KLR-chip for quicker spool-up ? How come nobody else has done it before ? Am I missing something here ?
How much is the over-boost cut-off limit increased in your KLR-chips?
All we could wish for now is KLR+CV controlled boost using feedback (there is already a tube from the manifold to the KLR...) for precise boost control.....
Any plans for that ???? ;-)

Cheers,
Tommy

promax_motorsport

Hi Tommy,

I can't claim to have written these particular chips, they have been developed by a Motorsport company in Germany where the 944 Turbo has become eligible for Historic Motorsports and hence, is receiving a little more interest in Germany than it has of late.

The Overboost Protect level is actually located on the DME chip, this determines the maximum level of tolerated boost. The MAF DME/KLR combo tolerate a maximum overboost of 1.1 bar (~16psi) and are designed to operate to 1.0 bar of boost. NOTE: the boost is not purely regulated by the KLR - this is determined in part by the wastegate (which needs to be shimmed to support 1.0 bar). If the wastegate is too weak to hold boost, the KLR may only still achieve a maximum of 0.7 bar or less - this is why there needs to be some pre-load on the wastegate spring. The beauty of this chipset is that the full safety mechanisms are still deployed when necessary (knock & temperatre induced ignition retard and overboost protect)

This again is bourne out of the need by a growing mumber to have discreet modifications on their 951 - no visible boost controller; cone filters or in fact anything that indicates a higher state of tune than standard.

The reason most don't bother with re-mapping the KLR is because it's easier to just disable the function and run Manual Boost Control. The KLR can only sense up to 1.0 bar of boost as well (as standard). Hence, it requires a higher rated pressure sensor to be of any use for high boost applications. Personally I like the idea and will continue to investigate further. What I really want to do is have a programable interface to the KLR allowing boost levels to be set (as the DME scales the fuel automatcally based on boost and load / AFM signal) and also adapt the system to support a Dual Port Wastegate in a similar way that an EBC (such as a Greddy Profec or APEXi) does - but with the benefit or being integrated with the DME. An interesting concept, but achievable I think.

My own car is a totally standard 1991 Turbo S, I just need to fix the crankshaft front oil seal (scheduled for Thursday). Once this is done, I plan to dyno the car as is - and then dyno again with the MAF Kit, MAF chips and 2 wastegate shims fitted. I'll let you all know the outcome.

Regards,
Andrew
www.promaxmotorsport.com

oi-punx

Definitely quite a difference vs. my own car. I can't comment on the top end because I did not take Efren's car above 45 mph, but from a stop and at low speeds the throttle response is absolutely better. Boost builds quickly, noticeably quicker than on my own car (K26/6), and more quickly than I remember from the times I have been in Efren's car previously. While viewing the zeitronix output on Efren's laptop during the initial test run I can say that the car was overboosting compared to the stock AFM and had to be adjusted down several times. The car revs more freely and feels more like the NA 944 as anyone who has driven a MAF equipped 951 knows.

The MAF package is very nice. The appearance is that of a stock car, and installation was very easy, similar to installing a boost gauge for reference. Like Efren, these features are more important to me than maximum power output.

Time will tell how the kit does regarding emissions and long-term reliability. First impressions on it are very good and I am currently weighing the purchase. No affiliation with ProMax or Andrew, just my own perception.

tommye

As far as I've guessed, the KLR controls the CV to operate with a certain duty-cycle, variable according to needs. This is done via look-up tables, so it's assuming a certain WG-springrate.
By clamping the WG-control line,one can get up to 25 psi or so of boost (correct, or is this with harder WG-spring?), and in limp-home mode, the CV is kept wide open limiting boost to 0.2 Bar or so. So, anything between these 2 boost pressures should be easy to obtain by just modifying the duty-cycle of the CV. Correct me if I'm wrong...

Tommy

marcoturbo

Andrew, what are the main difference between the Guru chips you used to sell and the chips you currently sell ? Do they also come from Germany ?

tommye

Andrew,
I just came to think of something else:

The factory system uses the AFM signal to meter fuel delivery up to a certain limit - up to the point where the AFM door is fully open (which happens before max. rpm), from there on, only the rpm signal is used (maybe in conjunction with the WOT switch).

How about your system (MAF + chips), is this method retained or is the MAF signal used all the way to redline/max flow??? If yes, this would be a great advantage for having safe/correct fuelmix not only for a given max. boost level, but also for those who like to modify max. boost often......

Cheers,
Tommy

promax_motorsport

Hi Marc,

We have two families of chips. The first are designed for manual boost control and are similar in principle to what you have (i.e. work with a inline boost controller or Dual Port Wastgate with external boost control). These are made in house by ProMAX Motorsport.

The second are designed specifically to emulate the factory originals but are designed to work up to 1.0 bar and retain all factory protect mechanisms. These are what we recommend for standard cars running a MAF - as it supports the 'keeping it standard' look and really makes the most of the MAF set-up (these are not designed by ProMAX, but have been thoroughly tested and are hence supported and recommended).

The MAF will work fine with either - but we have been getting more demand to supply more stealth looking product - hence the above.

Regards,
Andrew
www.promaxmotorsport.com

promax_motorsport

Hi Tommy,

There is still a degree of scaling of the fuel even at WOT - another reason why it's good to use chips following the factory principle.

However, on cars with manual boost control and an effectively redundant KLR - more air will flow at WOT resulting in the boost increasing. As the 944 Turbo is effectively needing to fuel to suit boost, you just drop it down as Efren did. You will still have higher boost in 1st and 2nd gears and also much faster turbo spool up. Either way, you win with the MAF! :-)

Regards,
Andrew
www.promaxmotorsport.com

promax_motorsport

Hi Tommy,

This is correct, the KLR values control the CV activation and boost is regulated from the level supported by the wastegate (0.2 bar as standard) to .75 bar (on the standard car). The wastegate will also limit the maximum boost as it is a weak spring and will be forced open by exhaust gas ultimately (as in clamping the wastegate line).

So boost levels are dependent on how well the wastegate is sprung as well as the lookup values on the KLR chip. Boost is regulated by the KLR between a maximum and minimum value - rather than controling absolute values.

Regards,
Andrew
www.promaxmotorsport.com

danny951

I have confirmed that you can get very high boost (over 20psi) with the stock turbo and stock wastegate (even not shimmed) by clamping the line to the wastegate. So, why do people say the stock wastegate cannot hold a high boost level? Isn't the reason that boost drops on a stock car because the KLR is programmed to open the wastegate at 5100 rpm (can't remember the exact RPM)? And tommye's right, the KLR has never really been "tapped into" to provide better boost control using the CV.

marcoturbo

Andrew, so the second family of chips you're talking about are designed to work with the stock cycling valve instead of a MBC ?

Is there any horsepower benefit with these "new" chips in relation to the Guru/Promax ones ? Any dyno chart ?

tommye

Olli,
Do you have any more info ? Photos ????

IanS

The idea of controlling a dual port wastegate from the factory KLR sounds very interesting.

No chance you're going to come out with an ignition upgrade as well sometime in the near future?

Keep up the good work, its always nice to have a few more options out there.

Olli Snellman

It looks completely stock. He just removed all internal parts of the original AFM. he even uses AFM's original temp sensor, so also the wiring looks stock.