MY99/00 - GEMS or Simtek
 

Whats the better choice of ECU, Gems or Simtek for a MY99/00 phase 2 car? Looking for something that will allow Maf removal, AL, LC, dual fuel maps if possible.

I understand there is 2 types of GEMS, the road & rally versions - I believe its a rally version as the seller has AL/LC enabled, awaiting conformation of exact version.

Or alternatively is Simtek a better option - reason for posting is I dont have a lot of background about GEMS.

Oh and who will map GEMS? (already sent Andy F an email and awaiting a response)

Gems has crap cold start and idle, if the car is a daily driver go for the simtek

Is this a function of the fuel/ignition maps which cant be overcome? Having had an Apexi PFC it wasnt always the best for cold starts compared to OE, so is the Gems likely to be worse or more problematic than that?

I had a power fc mapped by Simon for 4 years, absolutely perfect in every condition no issues at all only changed as I bought a syvecs.

Bought an sti 5 with a gems fitted, used to struggled to start from cold, would cut out when coming to a stop and idle would hunt. Simon had a look at it and made it slightly better but ultimately not a patch on the power fc.

Cheers Banny, I will see what feedback I get from Andy F, obviously if the idle is that erratic and certainly dont want issues with the car cutting out then perhaps its a no go for my applications. While the car isnt a daily, I wouldnt want something thats so rough an idle it prevents being able to sit in traffic etc - its not a fully dedicated track/rally car.

Are idle issues on Simtek common at all as it would run using a MAP sensor too?

I ran one for a week when I went rotated turbo, was mapped to the previous owners spec and I drove the car locally and then from Yorkshire to surrey for mapping. Got stuck in a traffic jam for an hour but it idled perfectly and drove spot on up to 4k revs :thumb:

My old GEMS was mapped by Steve Simpson whose regarded as one of the best for this ecu, only problem i had was even the slightest corrosion on any crimps wether battery or the main body earth points caused really bad hesitation. Finally got to the bottom of it when another GEMS owner had same problem.

Get a sim tec just make sure you get a well know mapper to map it not some of the cowboys out there

The GEMs was never designed for the road performance market and what geared primarily for competition and rally cars mostly. In that case the customer would not be bothered about good starting or good idle as it would be more than likely that the car would be running a jacked open throttle. This meant certain tables and settings were deliberately not added for that reason. The 99 finished being developed nearly 8years ago and even though the newer gems for the later cars has better options it still doesnt meet or exceed the oem ecu or the abilities of theSimtek in terms of starting and idling.

So basically get a Simtek!

I hope that helps.

Graham

My Gems idles perfectly after Bob mapped it & starts on the second go from cold which I'm quite happy about as it gets the oil pressure up!

Thanks for the responses guys. Looks like it will be a Simtek I go for then and dont worry no cowboys getting used - car will be mapped by Andy Forrest.