Anyone with GEMS?
Discussion
Hey, is there anyone on here that have completed or in the process of a GEMS conversion?
I just wondering as I've not heard anyone talking about it for some time and I've got mine ready to be completed as part of the body off rebuild.....I'm hoping to get it on the road before it snows!!
I just wondering as I've not heard anyone talking about it for some time and I've got mine ready to be completed as part of the body off rebuild.....I'm hoping to get it on the road before it snows!!
Hi Adrian,
Yes I'm still working towards installing GEMS, I'll have it complete one of these years! We met at a Mark Adams rolling road session somewhere over Telford way last year if you recall.
I've been delayed by needing to rebuild my gearbox which I've nearly completed, just waiting for some new mounts to accommodate the s10 tail housing that I decided to do whilst rebuilding the gearbox.
I've also fitted a new TTV lightweight steel flywheel with the GEMS trigger pattern machined into the back and a new AP racing clutch to improve the pedal weight.
I had hoped to have it all done by the start of April, but work demands constantly get in the way. As I've missed the start of the season, I'm tempted now to bash on with the remainder of the conversion and get it back on the road later this year or certainly ready for next April...watch this space
Yes I'm still working towards installing GEMS, I'll have it complete one of these years! We met at a Mark Adams rolling road session somewhere over Telford way last year if you recall.
I've been delayed by needing to rebuild my gearbox which I've nearly completed, just waiting for some new mounts to accommodate the s10 tail housing that I decided to do whilst rebuilding the gearbox.
I've also fitted a new TTV lightweight steel flywheel with the GEMS trigger pattern machined into the back and a new AP racing clutch to improve the pedal weight.
I had hoped to have it all done by the start of April, but work demands constantly get in the way. As I've missed the start of the season, I'm tempted now to bash on with the remainder of the conversion and get it back on the road later this year or certainly ready for next April...watch this space
How we doing?...Yes, I remember. It's good to hear I'm not on my own with being behind schedule!
My original plan was to have it back on the road late last summer, but a psycho ex and nearly 5 years of court has put a BIG hole in my funds and a little knock to my enthusiasm.....but I'll get there in the end! Lol
My original plan was to have it back on the road late last summer, but a psycho ex and nearly 5 years of court has put a BIG hole in my funds and a little knock to my enthusiasm.....but I'll get there in the end! Lol
I really don't get why people would bother with Gems.
It's too niche in my view.
I'd go for Powers MBE, Omex or Emerald or maybe at a push the Canems that Lloyds offer although the wiring loom that they spec looks a bit naff.
The Gems is a right faff and sometimes relies on used parts
If it's a DIY route you want Omex and or Emerald can supply all the parts.
Most of all these are widely supported and many people can map the system.
It's too niche in my view.
I'd go for Powers MBE, Omex or Emerald or maybe at a push the Canems that Lloyds offer although the wiring loom that they spec looks a bit naff.
The Gems is a right faff and sometimes relies on used parts
If it's a DIY route you want Omex and or Emerald can supply all the parts.
Most of all these are widely supported and many people can map the system.
urquattroGus said:
I really don't get why people would bother with Gems.
It's too niche in my view.
Unlike all the aftermarket stuff that was developed primarily with motorsport in mind, GEMS is an OEM system that has had megabucks thrown at it to ensure it will perform consistently in any condition your car will ever encounter, now and 100,000 miles on when the throttle-based maps on your aftermarket jobbie won't be so compatible with the reality of your slightly worn engine anymore. The looms are available brand new, and they're made to OEM standard - not soldered together in someone's shed. You gain OBD2 functionality so any Land Rover dealer anywhere in the world can do a 'first line' diagnosis if you ever get stuck in the boons. It's too niche in my view.
Most of all, it's a fit and forget solution. Once the ECU is unlocked to work as a standalone unit and a target air/fuel ratio is being programmed in for every load/rpm point on the map, it will adapt to these values regardless of conditions. Even at 25 years old, its adaptation strategies are beyond what any but the most high end aftermarket solutions have on offer, and it's all plug and play.
If you like to tinker, by all means go aftermarket.
If you want something that just works, I would urge you to strongly consider GEMS (provided you have one of the later serpentine blocks with provisions for knock sensors, conversions on older blocks are possible but would involve fabrication and probably some experimentation to get correct knock sensor readings). Once it's done, it's done for good
Edited by 900T-R on Friday 12th April 13:35
I decided to do a GEMS conversion after reading the article in the TVR Sprint magazine mentioned by Blitz. Started it that winter and finished ready for the good weather in 2018. It's made a big difference to how my car drives.
The block I have has the castings but just not machined for the Knock and crank sensor. I taped my own threads for the knock sensors and drilled out the hole for the crank sensor and made my own mounting. For the cam sensor I decided to do a modified distributor.
Then created my own harness using the diagrams available in the RAVE resource, it details all the wire sizes etc.
If anyone wants any info just ask, happy to help where I can.
The block I have has the castings but just not machined for the Knock and crank sensor. I taped my own threads for the knock sensors and drilled out the hole for the crank sensor and made my own mounting. For the cam sensor I decided to do a modified distributor.
Then created my own harness using the diagrams available in the RAVE resource, it details all the wire sizes etc.
If anyone wants any info just ask, happy to help where I can.
900T-R said:
Unlike all the aftermarket stuff that was developed primarily with motorsport in mind, GEMS is an OEM system that has had megabucks thrown at it to ensure it will perform consistently in any condition your car will ever encounter, now and 100,000 miles on when the throttle-based maps on your aftermarket jobbie won't be so compatible with the reality of your slightly worn engine anymore. The looms are available brand new, and they're made to OEM standard - not soldered together in someone's shed. You gain OBD2 functionality so any Land Rover dealer anywhere in the world can do a 'first line' diagnosis if you ever get stuck in the boons.
Most of all, it's a fit and forget solution. Once the ECU is unlocked to work as a standalone unit and a target air/fuel ratio is being programmed in for every load/rpm point on the map, it will adapt to these values regardless of conditions. Even at 25 years old, its adaptation strategies are beyond what any but the most high end aftermarket solutions have of offer, and it's all plug and play.
If you like to tinker, by all means go aftermarket.
If you want something that just works, I would urge you to strongly consider GEMS (provided you have one of the later serpentine blocks with provisions for knock sensors, conversions on older blocks are possible but would involve fabrication and probably some experimentation to get correct knock sensor readings). Once it's done, it's done for good
Who does 100,000 miles in their TVR though? a few thousand miles a year for most?Most of all, it's a fit and forget solution. Once the ECU is unlocked to work as a standalone unit and a target air/fuel ratio is being programmed in for every load/rpm point on the map, it will adapt to these values regardless of conditions. Even at 25 years old, its adaptation strategies are beyond what any but the most high end aftermarket solutions have of offer, and it's all plug and play.
If you like to tinker, by all means go aftermarket.
If you want something that just works, I would urge you to strongly consider GEMS (provided you have one of the later serpentine blocks with provisions for knock sensors, conversions on older blocks are possible but would involve fabrication and probably some experimentation to get correct knock sensor readings). Once it's done, it's done for good
Edited by 900T-R on Tuesday 9th April 11:56
I fitted Omex to my 1966 Alfa 5 years ago. The only ongoing adjustment has been to re balance the throttle bodies once and servicing.
The article read in sprint magazine made Gems fitment seem much more complicated than aftermarket. For starters it doesn't use a normal crank position sensor. It has one on the flywheel etc...?
Gems was a good system at the time but I maintain that it's a niche product.
If this was Bosch Motronic or something then I could understand the argument.
Similarly I have Powers supplied MBE on my Griff, simple but effective using a high quality loom and all new components. Requires nothing more than routine maintenance.
I dont know enough about the technicals to make a convincing arguemwnt to other people about GEMS, but its seems like the logical upgrade to me.,
My upgrade 'should' be simple plug and play as I purchases all the requires parts from Mark Adams, Inc a brand new ecu. In fact all the parts have been brand new Inc the loom but bar the AFM.
I had the engine rebuild by V8D with GEMS in mind so Rob fitted a gems cam, modified front cover and added a crank sensor to the flywheel.
Theres other great aftermarket options out there but I don't think they'll be quite as good as a factory developed system and I hazard to guess there's many multiple times the numbers of gems units out running in the world than any of its alternatives such as emerald and the like, so not sure how "niche" gems is?
It's ability to self map and factory developed knock sensing must make it 'probably' the best we can fit!
My upgrade 'should' be simple plug and play as I purchases all the requires parts from Mark Adams, Inc a brand new ecu. In fact all the parts have been brand new Inc the loom but bar the AFM.
I had the engine rebuild by V8D with GEMS in mind so Rob fitted a gems cam, modified front cover and added a crank sensor to the flywheel.
Theres other great aftermarket options out there but I don't think they'll be quite as good as a factory developed system and I hazard to guess there's many multiple times the numbers of gems units out running in the world than any of its alternatives such as emerald and the like, so not sure how "niche" gems is?
It's ability to self map and factory developed knock sensing must make it 'probably' the best we can fit!
900T-R said:
urquattroGus said:
I really don't get why people would bother with Gems.
Unlike all the aftermarket stuff that was developed primarily with motorsport in mind, GEMS is an OEM system that has had megabucks thrown at it to ensure it will perform consistently in any condition your car will ever encounter, now and 100,000 miles on when the throttle-based maps on your aftermarket jobbie won't be so compatible with the reality of your slightly worn engine anymore. The looms are available brand new, and they're made to OEM standard - not soldered together in someone's shed. You gain OBD2 functionality so any Land Rover dealer anywhere in the world can do a 'first line' diagnosis if you ever get stuck in the boons. Most of all, it's a fit and forget solution. Once the ECU is unlocked to work as a standalone unit and a target air/fuel ratio is being programmed in for every load/rpm point on the map, it will adapt to these values regardless of conditions. Even at 25 years old, its adaptation strategies are beyond what any but the most high end aftermarket solutions have of offer, and it's all plug and play.
If you like to tinker, by all means go aftermarket.
If you want something that just works, I would urge you to strongly consider GEMS (provided you have one of the later serpentine blocks with provisions for knock sensors, conversions on older blocks are possible but would involve fabrication and probably some experimentation to get correct knock sensor readings). Once it's done, it's done for good
Edited by 900T-R on Tuesday 9th April 11:56
What 900T-R said.
urquattroGus said:
It's too niche in my view.
I'm not sure 'niche' is the best way to describe an OBDII OEM system designed for the specific engine. But that term would almost certainly describe after-market ECU's. In fairness they're all limited markets.There's nothing wrong with Omex and Emerald et al, lots have them fitted and I have considered them all but as 900T-R says GEMS is fit and forget and so will suit me just fine.
Mbe is built for the job and does the job.
So are many others including Gems, knock sensing is not something you really need on a light powerful car until your at high revs.
Decent mapping will achieve the same thing, optimum settings in a safe manner.
All this ones better than the other lark,,, a modern system with mapper friendly software can be fettled by lots of skilled people the glode over, after market all use a very similar platform and mappers can read them in an instant.
A sports Ecu is a very robust thing.
There are very many good reasons to use a modern Ecu that gives instant throttle response and accurate sensor readings, that’s all it really does, over complicated it doesn’t need to be.
A proper water tight loom is one of the most important considerations in all of this if you want O/E quality and reliability in poor cold wet weather. It has to start down to -20 if you ask me. I’ve started my Mbe car without a stepper motor ( shock horror ) at -10 a piece of piss.
If it’s done right they all improve the car massively really.
but one better than another,,, splitting hairs comes to mind.
The bloke mapping it is possibly more important than what Ecu is fitted. Once it’s mapped you should have years of free driving. Most cars at 70,000 are still on original chip so as most modern Ecu appapt it will be sometime before you fall out of tune and even then just changing the percentages in thevsoftware of how much it will adapt can be made.
If your engines reliability and VE is falling away the map can only do so much in any case.
So are many others including Gems, knock sensing is not something you really need on a light powerful car until your at high revs.
Decent mapping will achieve the same thing, optimum settings in a safe manner.
All this ones better than the other lark,,, a modern system with mapper friendly software can be fettled by lots of skilled people the glode over, after market all use a very similar platform and mappers can read them in an instant.
A sports Ecu is a very robust thing.
There are very many good reasons to use a modern Ecu that gives instant throttle response and accurate sensor readings, that’s all it really does, over complicated it doesn’t need to be.
A proper water tight loom is one of the most important considerations in all of this if you want O/E quality and reliability in poor cold wet weather. It has to start down to -20 if you ask me. I’ve started my Mbe car without a stepper motor ( shock horror ) at -10 a piece of piss.
If it’s done right they all improve the car massively really.
but one better than another,,, splitting hairs comes to mind.
The bloke mapping it is possibly more important than what Ecu is fitted. Once it’s mapped you should have years of free driving. Most cars at 70,000 are still on original chip so as most modern Ecu appapt it will be sometime before you fall out of tune and even then just changing the percentages in thevsoftware of how much it will adapt can be made.
If your engines reliability and VE is falling away the map can only do so much in any case.
Edited by Classic Chim on Tuesday 9th April 14:39
Boosted LS1 said:
An O/E system will have had thousands of hours of dyno time spent on it under all sorts of simulated conditions and they will have used multiple engines. This is far to expensive for the average person.
My map has load sights every 200 revs I think it is? It wouldn’t take a genious of a mapper used to cux maps to create maps for another system using much of that data I’d have thought. All I know is my map seems spot on everywhere and the car pulls and drives faultlessly. I’m not sure how hours on dyno count for much when all of a sudden you have half the weight of the vehicle, big cam, fast flowing pipes etc. What good is all that data from vehicles used for a very different application.
Clearly there are arguments for and against in the Gems vs aftermarket stand alone ECU debate, the truth is there are probably hundreds of TVRs out there now that have been running reliably for years and many tens of thousands of miles on MBE, Canems, MegaSquirt and Emerald ECUs and only one or two on the Gems system so far, I myself have been running my Chimaera on the Canems system for some seven years now.
An important point seldom discussed is that all the commonly discussed ECUs for our cars run batch fired semi sequential injection where as the Gems is fully sequential, some will try to have you believe there is little benefit in going fully sequential, seven years ago years ago I had the semi vs fully sequential debate with Lloyd Specialist Developments. At the time Lloyds insisted valve events are happening so fast there couldn't possible be any real benefits going fully sequential, I was not 100% convinced by this argument but as at the time only semi sequential was on offer I went with that.
My argument was that all engine management systems have been fully sequential for years and manufactures aren't doing it for fun, fast forward seven years and Lloyds themselves are now offering a fully sequential Canems system, indeed they have fitted this to their own Chimaera with the addition of Wildcat heads and 108 degree exhaust manifolds and their bespoke tunnel ram inlet manifold, clearly they changed their mind on the benefits of fully sequential injection and decided to throw everything at their own Chimaera.
In my opinion it's well worth going the extra mile with fully sequential injection as I'd be very surprised if it didn't offer a smoother idle, even better low speed urban driving characteristics, a small but measurable improvement in fuel economy and lower emissions. A friend of mine has just had a fully sequential MoTeC ECU fitted to his 1968 Porsche 912, the engine is now a 3.0 six from a mid 80's 911 on throttle bodies running twin plug heads and coil on plug ignition. OK so it's a completely different engine to our Rover V8 and a flat six in an inherently balanced engine configuration but boy is it smooth and rev happy, especially for an engine on throttle bodies which are notoriously tricky when it comes to the mapping process.
Perhaps it's all about keeping costs down and the challenge of fitting a cam position sensor on an earlier Rover V8, but I'm surprised more of the usual aftermarket ECU suspects aren't offering a fully sequential upgrade for Chims & Griffs, as it stands only Lloyds seem to offer it with their fully sequential Canems system. Saying that I'm sure the guy who installed the fully sequential MoTeC ECU on my mates Porsche will be happy to put the same system on a TVR, trouble is it wasn't cheap so I suspect most TVR owners would bulk at the cost?
I'd be interested in what Jules (spitfire4v8) has to say on the semi vs fully sequential injection debate, so lets hope he tunes into this one to share his knowledge and experiences
An important point seldom discussed is that all the commonly discussed ECUs for our cars run batch fired semi sequential injection where as the Gems is fully sequential, some will try to have you believe there is little benefit in going fully sequential, seven years ago years ago I had the semi vs fully sequential debate with Lloyd Specialist Developments. At the time Lloyds insisted valve events are happening so fast there couldn't possible be any real benefits going fully sequential, I was not 100% convinced by this argument but as at the time only semi sequential was on offer I went with that.
My argument was that all engine management systems have been fully sequential for years and manufactures aren't doing it for fun, fast forward seven years and Lloyds themselves are now offering a fully sequential Canems system, indeed they have fitted this to their own Chimaera with the addition of Wildcat heads and 108 degree exhaust manifolds and their bespoke tunnel ram inlet manifold, clearly they changed their mind on the benefits of fully sequential injection and decided to throw everything at their own Chimaera.
In my opinion it's well worth going the extra mile with fully sequential injection as I'd be very surprised if it didn't offer a smoother idle, even better low speed urban driving characteristics, a small but measurable improvement in fuel economy and lower emissions. A friend of mine has just had a fully sequential MoTeC ECU fitted to his 1968 Porsche 912, the engine is now a 3.0 six from a mid 80's 911 on throttle bodies running twin plug heads and coil on plug ignition. OK so it's a completely different engine to our Rover V8 and a flat six in an inherently balanced engine configuration but boy is it smooth and rev happy, especially for an engine on throttle bodies which are notoriously tricky when it comes to the mapping process.
Perhaps it's all about keeping costs down and the challenge of fitting a cam position sensor on an earlier Rover V8, but I'm surprised more of the usual aftermarket ECU suspects aren't offering a fully sequential upgrade for Chims & Griffs, as it stands only Lloyds seem to offer it with their fully sequential Canems system. Saying that I'm sure the guy who installed the fully sequential MoTeC ECU on my mates Porsche will be happy to put the same system on a TVR, trouble is it wasn't cheap so I suspect most TVR owners would bulk at the cost?
I'd be interested in what Jules (spitfire4v8) has to say on the semi vs fully sequential injection debate, so lets hope he tunes into this one to share his knowledge and experiences
Sequential, that's what I forgot was the extra bonus to the gems.
Talking with Clive Ford last week about his equal length manifolds and he did mention gems not requiring a change to 'firing order' if I've got that right?
I sold my 'never fitted' cf standard manifolds last week to a guy who needed them, so looks like I'll be going the whole hog with the equals.
I never raised this thread as a which system better?....Just curious as to who gone along this route as well as me.
Talking with Clive Ford last week about his equal length manifolds and he did mention gems not requiring a change to 'firing order' if I've got that right?
I sold my 'never fitted' cf standard manifolds last week to a guy who needed them, so looks like I'll be going the whole hog with the equals.
I never raised this thread as a which system better?....Just curious as to who gone along this route as well as me.
Sadly Dave I cant offer any first-hand experience of sequential v semi seq v batched as the emerald I use doesn't as yet support 8 cyl full sequential - only semi seq (4 by 2 inj) , but I've done plenty of batch/bank fired cars (2 by 4 inj) over the years running smoothly too.
I've no doubt there will certainly be benefits in emissions / economy as these are what primarily drive the advancements in this area for OE fit systems .. stricter and tighter control over emissions especially I guess as no car seems to be able to meet its published economy figures
and it seems some manufacturers have to bend the rules to meet emissions targets too from recent press stories anyway.
I've heard it said that going full sequential brings smoothness benefits too, but again I have no first hand evidence. You'd need the same car mapped by the same mapper running each strategy to come up with a decision.
If the emerald offered full seq for 8 cyls (it does up to 6 cyls full seq) then I'd probably offer it and let the customer decide if it was value for money .. but right now I think I'd be offering it more because I could rather than because I feel I should, but blatant up-selling isn't my style.
I've no doubt there will certainly be benefits in emissions / economy as these are what primarily drive the advancements in this area for OE fit systems .. stricter and tighter control over emissions especially I guess as no car seems to be able to meet its published economy figures
and it seems some manufacturers have to bend the rules to meet emissions targets too from recent press stories anyway.I've heard it said that going full sequential brings smoothness benefits too, but again I have no first hand evidence. You'd need the same car mapped by the same mapper running each strategy to come up with a decision.
If the emerald offered full seq for 8 cyls (it does up to 6 cyls full seq) then I'd probably offer it and let the customer decide if it was value for money .. but right now I think I'd be offering it more because I could rather than because I feel I should, but blatant up-selling isn't my style.
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