New Emerald to be.

[motul1974]

I here what you're saying and can do nothing but bow down to your greater experience on the gas, buy I will say though, the system on my RRC, as crude as it is, is genuinely rather good...runs better on lpg than on petrol infact. I guess that's why I've been impressed with lpg and would like to further improve things.

Who knows, one day lpg might be the ONLY economic way to run our cars!!!

[QBee]

Certainly is with my big Volvo. 2.9 T6 petrol, my daily drive. 19-22 mpg on petrol, on the longer drives on LPG I am getting the equivalent of 40 mpg. Carries the entire family, dogs, luggage etc.

[450Nick]

motul1974 said:

No, but seriously, how about plenums....are these also the recommended to the rv8 using gems, I assume it is?

Id love a carbon twin plenum....but only if it truly added credible performance.

No, you can use any plenum that you like as long as you use a Delphi 4 wire stepper motor, the AFM and thottle pot, I'm just using the standard TVR one but with a plenum spacer and superflare carbon 45mm trumpets.

[450Nick]

ChimpOnGas said:

There's a lot of genuine advantages, this is probably the most interesting upgrade we've seen all year, maybe in years

A a Lucas-Sagem GEMS kit would be great option for those still on the 14CUX, sadly Mark Adams isn't know for moving quickly though

Mark is a very busy man the poor chap, but he has recently taken on some help and has a guy running the sales and website side of things along with some of the normal running of the business which is freeing Mark up to do a bit more than he used to be able to

[motul1974]

What ever happened to this? Sounds a great solution and I've totally put any engine mods on hold until I can find out more about it.
I figure I could spend the extra money saved using a gems on some hardware upgrades and get best bang for my limited buck!

[450Nick]

motul1974 said:

What ever happened to this? Sounds a great solution and I've totally put any engine mods on hold until I can find out more about it.
I figure I could spend the extra money saved using a gems on some hardware upgrades and get best bang for my limited buck!

Article has been submitted to Sprint a little while ago... Should be published soon?? My last hurdle was to built a small circuit to conditon the speedo pulse into GEMS' operating range which I've now completed and the car is all running, insured and MOT'd. Booked in with Mark Adams next Friday to set up the injector scaling (he's never done a GEMS with injectors as big as mine before so didn't have the pre-sets) then it's time to get out and drive it!

[motul1974]

Great, sounds like it's still something to hold on for. :-)

[s3c chris]

I have just read this thread and it sounds very intriguing!
An ECU that can map itself and give a smoother and better drive must be the way forward?
I look forward to reading the article and seeing the results of your conversion.
Keep us all informed, a bolt on conversion kit sounds very tempting.....

Regards Chris.

[MisterT]

450Nick said:

Article has been submitted to Sprint a little while ago... Should be published soon?? My last hurdle was to built a small circuit to conditon the speedo pulse into GEMS' operating range which I've now completed and the car is all running, insured and MOT'd. Booked in with Mark Adams next Friday to set up the injector scaling (he's never done a GEMS with injectors as big as mine before so didn't have the pre-sets) then it's time to get out and drive it!

Hi Nick, glad to hear yours GEMS conversion is behaving well and the cam position trigger is working. I'm at a stage where I just need to start fitting the GEMS bits and make up a loom, but now the decent weather is here I'm going to use the car over summer and go for the big install over next autumn/winter. Sounds like I'll need to check-in with you over the speedo pulse device.

[Brithunter]

450Nick said:

Article has been submitted to Sprint a little while ago... Should be published soon?? My last hurdle was to built a small circuit to conditon the speedo pulse into GEMS' operating range which I've now completed and the car is all running, insured and MOT'd. Booked in with Mark Adams next Friday to set up the injector scaling (he's never done a GEMS with injectors as big as mine before so didn't have the pre-sets) then it's time to get out and drive it!

As I am still learning about the TVR's and have to admit a lot of this is still somewhat confusing to me am wondering how much trouble would it be to upgrade say an early pre serpentine engine to this later GEMS system? As I assume the earlier engine has none of the required sensors etc.

[450Nick]

MisterT said:

450Nick said:

Article has been submitted to Sprint a little while ago... Should be published soon?? My last hurdle was to built a small circuit to conditon the speedo pulse into GEMS' operating range which I've now completed and the car is all running, insured and MOT'd. Booked in with Mark Adams next Friday to set up the injector scaling (he's never done a GEMS with injectors as big as mine before so didn't have the pre-sets) then it's time to get out and drive it!

Hi Nick, glad to hear yours GEMS conversion is behaving well and the cam position trigger is working. I'm at a stage where I just need to start fitting the GEMS bits and make up a loom, but now the decent weather is here I'm going to use the car over summer and go for the big install over next autumn/winter. Sounds like I'll need to check-in with you over the speedo pulse device.

Hi Mike! Glad to hear you're still moving forward with it - of course, if you need any help with it just give me a shout. I definitely hear you about doing it over winter. I wanted to drive mine so bad last year but I don't have a garage so have to do all of my work when it's warm and light outside... The speedo device took a bit of time to work out - I upgraded the sensor to something which reads below 5mph unlike the TVR standard one, then have created this magic box shown below. It takes the signal and outputs one feed to the speedo, and another to the GEMS ECU which is actually half speed so the ECU knows when you're moving and when you're not, but also you can't hit the inbuilt speed limiter (unless you can get the car to go around 240mph haha). I can either show you how to make one, or I can make you one (or maybe do a little run of them if need be) for a few beer tokens..

Edited by 450Nick on Thursday 13th April 10:15

[motul1974]

Looks like you're reaching 'Take Off' on this project! :-)
I loomed at MA Web site for the ecu - cica £600. Could this make a kit quite expensive do you think nick?

[450Nick]

motul1974 said:

Looks like you're reaching 'Take Off' on this project! :-)
I loomed at MA Web site for the ecu - cica £600. Could this make a kit quite expensive do you think nick?

At long last it seems so! I've not driven the car regularly for a very long time now so I'm super excited for summer... (though I've already started planning the next mod ).

Yes the ECU with Mark's midas touch applied to it does cost a few quid. In the article I've put a small table with all of the parts required and the prices I could find everything for (new or second hand depending on the item) but it amounts to somewhere between 1 and 2k depending on how many new parts you use, and what state you buy the loom in. I suspect mine was towards the lower end, though I did a lot of work myself and put the time in instead. Where you save though is in the long term. Due to the fact you don't really need to put it on the rollers, you save a lot of money and hassle in the setup of the system, and beyond that it runs its self, so it really should never need additional money putting into it whereas I think any aftermarket system will need refining and likely remapping if you change anything - GEMS doesn't. Also, if you look at GEMS' list of capabilities (full sequential fuel & sparks, individual cylinder trimming, knock control, advanced self mapping, OBD etc etc), the only competitors you'll find are in the fully specc'd Motec kind of end of the market, and for that you're looking at £3-4k plus mapping, and it still won't quite be as good for road use as a GEMS. So relatively speaking, GEMS is a complete bargin.

[450Nick]

Brithunter said:

As I am still learning about the TVR's and have to admit a lot of this is still somewhat confusing to me am wondering how much trouble would it be to upgrade say an early pre serpentine engine to this later GEMS system? As I assume the earlier engine has none of the required sensors etc.

Unfortunately an early pre-serp isn't going to be easy to convert. The main issues are that you need the serpentine front cover (known as an intermediate one in Rover V8 terms), and also the later block as it has the knock sensor bosses built into it (and the coil pack mounting bosses up top). So it would be easier to just start with a 4.6 engine and sell your pre-serp, which is still perfectly do-able (TVR engines come out pretty easily and fetch good money).

[motul1974]

I think if a complete 'reliable' kit can be sourced for under £1500, then there would be a big demand , especially if upgrading the non serp engines could be done effectively, bit my problem, but be nice to think such an upgrade would be available to all.
OEM developed upgrades are often much under sold, with sexier aftermarket stuff often being the center of attention - same with other brands.

[Brithunter]

450Nick said:

Unfortunately an early pre-serp isn't going to be easy to convert. The main issues are that you need the serpentine front cover (known as an intermediate one in Rover V8 terms), and also the later block as it has the knock sensor bosses built into it (and the coil pack mounting bosses up top). So it would be easier to just start with a 4.6 engine and sell your pre-serp, which is still perfectly do-able (TVR engines come out pretty easily and fetch good money).

OK thank you........................... have not bought my TVR as yet but have seen a nice early 4.3 advertised. Of course it may not still be on offer by the time the funds are available but needed to know and now I do.

I prefer the earlier style Chimaera to the late one just one reason for considering a 4.3 or 430 am going to have to give this a little more thought now.

[andy43]

Cheap route to a Gems system is here - http://www.ebay.co.uk/itm/1998-RANGE-ROVER-LIMITED...
Remove Gems system, sell on what's left.
The whole engine may be worth keeping bearing in mind it's been top-hatted and had 5k spent on it.