anyone had experience of both, differences?
martin

 

Simtek all day long.

Loads more features and far smoother due to using MAP not MAF.

 

agree
new simtek user mapped by steve simpson fun all the way

plus if you get the software and dongle you can fiddle with the map yourself (if you know how) so you can make mild adjustments for dif weather conditions, test save the map and then load the one you want to use when it suits, eventually buld your own arsenal of maps to suit....

yes i am a new fan

 

For your application Ecutek would be better value for money IMHO. You retain closed loop knock control and active diagnostics whilst spending less. These are genuinely valuable features on a road car that you won't get on aftermarket ECUs.

MAF deletion is a double edged sword as you lose management information. Manifold Pressure alone doesn't tell you how much air is going into the engine without taking inlet temperature and volumetric efficiency into account, issues which a MAF based system won't have.

It can however be of marginal benefit if you have a FMIC or a big roller bearing turbo that is causing reversion in the inlet.

 

Most simtek ecu's fitted will have a temp sensor fitted to the inlet.

 

This is a difficult comparison to make as I would agree that for very mildly modified cars the extra cost can be hard to justify.However on Andy has made some technical points that I would disagree on as follows:

SimTek has knock detection/warning and closed loop correction is shortly to be available.We still believe that visible knock warning is a valid tool against engine destruction.
With a 24x24 grid for fuel and ignition maps most customers report that driveability at part throttle is not compromised over the MAF based system.Where the MAP scores is on full throttle/boost zones where the MAF sensor starts to lose resolution as it has a non-linear relationship of Voltage-v-Air flow.i.e at high boost/air flows a larger and larger change in flow are required for ever decreasing change in voltage output.This compromises the ignition map resolution and hence engine performance.

Our ECU is very happy with the combination of MAP sensor and air temp sensor;it certainly doesn't seem to be "lacking management information"...

Steve

 

Hi Steve

I seem to have been misquoted, I said "you lose management information" when swapping from Ecutek to Speed/Density, not that your product is "lacking management information". Simtek appears to fit in the middle, assuming you run lambda and knock sensors then you have more sensor information than a GEMS and less than OEM/Ecutek/ESL.

When you delete the MAF I think we can agree that the airflow to the engine is no longer a known quantity. It is possible to estimate the airflow from a combination of MAF, MAT (Manifold Air Temp) and a V.E. table for a particular engine but from the practical examples of speed density systems I have seen, this isn't generally done.

How does Simtek treat its' MAT information?

Your comments about MAP vs MAF resolution at high load are interesting and it is an assumption I would challenge. While it is true to say that the MAF curve is exponential thus giving excellent low to mid load resolution, the resolution at higher loads is dependent on whereabouts on the curve you are operating. One of the ESL cars is a 400hp 20G/2 litre using an orange STi4 MAF and never sees more than 80% of max MAF headroom. The exponential nature of the MAF then works to its' advantage. The accurate measurement of airflow also takes into account the big swings of MAT that can occur on a dyno and seasonally in the real world.

I would say the real benefits of running MAFless include the removal of the small rich spike that can occur when lengthening the airpath on addition of a FMIC (although I've never noticed it from the drivers seat, it is apparent in the wideband logs), the removal of any headroom limit (only applies to 500+ hp cars really with the availability of Z32 and STi4 MAFs, and there is still an associated MAP headroom limitation) and immunity to airflow reversion near the compressor face for very large turbos (although again that can be mitigated by MAF location).

The addition of closed loop knock control would be an unusual addition in the aftermarket scene, probably because the amount of research that needs to be done to create a successful strategy without it being ineffective or costing power is immense. Ecutek and ESL have the good fortune of being able to borrow Subaru's algorithms and strategy which are likely to have had an appropriate amount of resource applied. From a control system perspective, we have always found the OEM ECU to be very stable.

Best Regards

Andy Stevens

 

simtek or ecutek for around 340 bhp on newage sti?

 

Can you use a z32 afm, as if you could that would eliminate the need to do away with the maf for mildly modded cars. I myself am looking into the same scenario, I am after between 350 and 400bhp, but the subaru maf doesnt seem anywhere near as good as some other manufacturers units, isnt there a way around this.