ACT Twin Throttle Carbon Fibre Plenum - Writeup
Discussion
k me thats a nice installation. 
pjac67 said:
MPoxon said:
BigGriff540 said:
Hi Mathew
Great write up!
I have a twin ACT plenum on my Griff which I have just purchased. Whats the difference between the standard throttle linkage and the Jenvey ones?
Thanks
Adam
Thanks Adam. I am not entirely sure what the actual benefit is Tim at ACT would be able to give you a better answer than me but I assume they give a better weight and feel to the throttle pedal. I have never driven one with the standard linkage so not able to give a direct comparison. I know Tim is selling these as a retro fit option.Great write up!
I have a twin ACT plenum on my Griff which I have just purchased. Whats the difference between the standard throttle linkage and the Jenvey ones?
Thanks
Adam
Adam - you DO NOT need quicker throttle response on your car (you may have Jenveys or similar already fitted...?).
Hopefully see you guys at GG. Paul.
Adam
wanna have this but coins already in a different project 
The old linkage did in fact require very careful installation and set up or you could suffer the throttle sticking open in unfavourable conditions (and yes, I've had that too 
). Personally I will only send out kits with the new, upgraded set up to customers for this very reason. OTOH now mine is working properly and reliably I'm not in a hurry to upgrade, at all.
Although the quicker throttle response is the main benefit of the twin and triple throttle plenum kits, we did find 12 bhp on John Eales' engine bench whe testing a 4.6 intermediate valve engine on an H218 cam IIRC, running GEMS, compared with the regular Lucas hotwire plenum.
). Personally I will only send out kits with the new, upgraded set up to customers for this very reason. OTOH now mine is working properly and reliably I'm not in a hurry to upgrade, at all. Although the quicker throttle response is the main benefit of the twin and triple throttle plenum kits, we did find 12 bhp on John Eales' engine bench whe testing a 4.6 intermediate valve engine on an H218 cam IIRC, running GEMS, compared with the regular Lucas hotwire plenum.
I have the triple carbón plenum plus rebored intake base and carbón trumpets since a few years now, ACT sent me then a remapped (by Mark Adams) tornado chip to match with it but I've always thought this juicy piece of hardware deserved a better box then the CUX14...what would be the best choice to give this intake the best electronic companion?
I've had some lenghty conversations with Mark about this in the past and as far as I remember there weren't any real problems converting any intermediate serpentine (read: post-1994 TVR) engines using OEM LR parts... I did propose that hes should put together a conversion kit with everything needed to do the conversion to take all the searchwork out of the process - which he thought an excellent idea but knowing his busy schedule and other more important stuff that life's been throwing at him, I guess that could take a while to materialise...
900T-R said:
I've had some lenghty conversations with Mark about this in the past and as far as I remember there weren't any real problems converting any intermediate serpentine (read: post-1994 TVR) engines using OEM LR parts... I did propose that hes should put together a conversion kit with everything needed to do the conversion to take all the searchwork out of the process - which he thought an excellent idea but knowing his busy schedule and other more important stuff that life's been throwing at him, I guess that could take a while to materialise...
Last thread about this:http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Ended with:
Mark Adams said:
spend said:
Hi Mark just for clarity as I understand it you are basically saying:
Rip out the Flywheel & replace with one from P46 (fairly rare manual version) + the engineering to lighten it.
Grind out the blank / casting in the block (opposite side to starter) and source the holder + sensor and tack weld it into the block.
Remove timing cover, drill out blanking in casting for cam phase sensor + drill & tap the clamping bolt, source the cam sensor & gasket.
Fit JE cam gear & a GEMS style cam shaft (Unless he has made the gear suitable for 3.9 style cams)
Source & fit the later style cam retainer (its different shape & diameters with the cam difference) which I'm not sure OTOMH if the block mounting holes / locations are the same?
Will the GEMS work OK without knock sensors or will it require the earlier blocks to be adapted to fix the knock sensors.
Hi DaveRip out the Flywheel & replace with one from P46 (fairly rare manual version) + the engineering to lighten it.
Grind out the blank / casting in the block (opposite side to starter) and source the holder + sensor and tack weld it into the block.
Remove timing cover, drill out blanking in casting for cam phase sensor + drill & tap the clamping bolt, source the cam sensor & gasket.
Fit JE cam gear & a GEMS style cam shaft (Unless he has made the gear suitable for 3.9 style cams)
Source & fit the later style cam retainer (its different shape & diameters with the cam difference) which I'm not sure OTOMH if the block mounting holes / locations are the same?
Will the GEMS work OK without knock sensors or will it require the earlier blocks to be adapted to fix the knock sensors.
It would be a lot of work to fit this system on a non-GEMS block, which sounds like the task you have listed. The honest truth is that you would probably be better off using a good quality after-market system instead to reduce the work, and as always I would recommend something like an Omex 710 (although nobody ever seems interested my recommendations on this subject).
If you are starting with a serpentine engine that already has the knock sensor bosses and crank trigger mounting, it is a lot easier. However it still currently involves lifting the engine in order to fit the crank sensor trigger ring, so is probably best considered only if the engine is being lifted for a rebuild.
John Eales does some fantastic lightweight flywheels for GEMS, although I do have a lightened P38 4.0 Litre manual flywheel in my Sierra 4.8. These weigh around 30 Pounds before lightening, so you wouldn't want to drop it on your foot! It is also possible to fix the trigger ring from an automatic flex plate to the back of the existing flywheel in certain circumstances, but I haven't checked for clearance on the TVR motor.
Currently I am working on a 5.1 litre version of the GEMS engine with John Eales, which has a cross-over manifold with throttle bodies and twin air flow meters. We are going to try some different triggers on the crankshaft pulley to see if we can get GEMS to accept them. Quite often this requirement is understandably a bit of a show-stopper for people considering the upgrade.
Out of interest, this engine will pass the California Smog Test. It has full Euro-III compliance with catalysts, four Oxygen sensors, and fuel tank pressure monitoring. It is currently cracking out about 385BHP, which will be "adequate" for the 700Kg Morgan that it's going in to!
There is a variant of GEMS that doesn't use the knock sensors, but obviously this would require mapping on the rollers since it cancels the individual cylinder mapping capabilities of GEMS. There are other pains with this version of the software, so I wouldn't recommend it really. Theoretically it would be possible to weld mounting bosses on each side of the block for the knock sensors, but getting them in the correct place could be a nightmare. Overall the machining could cost more than just using another block.
panic said:
I have the triple carbn plenum plus rebored intake base and carbn trumpets since a few years now, ACT sent me then a remapped (by Mark Adams) tornado chip to match with it but I've always thought this juicy piece of hardware deserved a better box then the CUX14...what would be the best choice to give this intake the best electronic companion?
The 14CUX is a very accurate ECU when it comes to fuelling and can happily work with high output motors if you fit the larger bosch airflow meter and high flow rate injectors. Where the 14CUX is let down is the mechanical ignition timing via the dizzy vacuum. The ideal solution is GEMS as others has said however not easy to retrofit especially if you have an earlier block without the bosses for the knock sensors. I am planning to get the car back to Mark Adams at some point this year to map up the plenum properly. I have already had the car mapped by Mark before and although mine will never win any BHP competitions the car drives very nicely indeed, pulls strong in every gear and is very well behaved in traffic and cold start etc which is exactly the result I want. I am not convinced that a lot of these aftermarket systems are capable of matching the accuracy of the 14CUX with an airflow meter for fuelling and general road manners. Headline BHP figures are one thing but getting the car to behave well and idle correctly are very difficult. I am considering going for an OMEX 200 ECU to control the spark and keep the 14CUX for fuelling. Mark reckons this will beef up the mid range torque and further improve the manners once mapped correctly. Interestingly enough Mark said that he had the 14CUX and OMEX200 system running on a customers car and he swapped it for an OMEX710 ECU to take over 14CUX and OMEX200 and there was no difference in the peak BHP figure.
^^^^ What he said. For the relatively relaxed fueling requirements of the RV8 concerning max torque/power, the CUX14 is more than adequately accurate and as for the rest of the oprating range I am not convinced a DIY aftermarket install will ever match the driveability and reliability of a well developed 1990s OEM management set up.
The ignition is where worthwhile advances in power/efficiency and driveability are to be had with relative ease. As said there is no reason why a CUX14/mapped ignition set up should perform less than and integrated aftermarket management system on these old engines.
The next step forward in terms of functionality that is actually desirable for roadgoing RV8s (knock sensing, adaptability to varying operating conditions and engine state of tune/maintenance, Euro III compatibility which might come in helpful as geovernments seem to be hellbent on driving older cars off the roads) GEMS really is the way forward even if it's a bit of a bugger to fit to most engines (less so if you replace the timing cover/ancillaries with the GEMS variant and use a JE flywheel specially designed for the job, only the knock sensors remain as potential show stoppers, but I'm sure a bolt-on solution wouldn't be spectacularly difficult to engineer - they're simply piezo pickups bolted to the engine block).
Of course, if you go to forced induction, nitrous or water/methanol injection etc. then an integrated aftermarket solution starts to make the most sense.
The ignition is where worthwhile advances in power/efficiency and driveability are to be had with relative ease. As said there is no reason why a CUX14/mapped ignition set up should perform less than and integrated aftermarket management system on these old engines.
The next step forward in terms of functionality that is actually desirable for roadgoing RV8s (knock sensing, adaptability to varying operating conditions and engine state of tune/maintenance, Euro III compatibility which might come in helpful as geovernments seem to be hellbent on driving older cars off the roads) GEMS really is the way forward even if it's a bit of a bugger to fit to most engines (less so if you replace the timing cover/ancillaries with the GEMS variant and use a JE flywheel specially designed for the job, only the knock sensors remain as potential show stoppers, but I'm sure a bolt-on solution wouldn't be spectacularly difficult to engineer - they're simply piezo pickups bolted to the engine block).
Of course, if you go to forced induction, nitrous or water/methanol injection etc. then an integrated aftermarket solution starts to make the most sense.
MPoxon said:
Yes I would be very interested to see the RR results. I am planning to get a session booked in with Mark Adams at TVR power to adjust the map to make the most of the plenum so I will keep you posted.
may be worth swapping the AFM for a larger one....just a thought as the 5AM is now a major bottle neck in your induction system... 20AM ??? best chat with MA as he will advise best, he steered me away from the Bosch for my car ohh forgot to say there is a haze of green envy when I look at your plenum
be interesting to see how the modifications we have both made affect the shape of RR graphs... your shiny carbon fibre plenum V my old RR plenum with enlarged throat
... a Growl Duel Edited by Hoover. on Saturday 24th May 09:24
Hoover. said:
MPoxon said:
Yes I would be very interested to see the RR results. I am planning to get a session booked in with Mark Adams at TVR power to adjust the map to make the most of the plenum so I will keep you posted.
may be worth swapping the AFM for a larger one....just a thought as the 5AM is now a major bottle neck in your induction system... 20AM ??? best chat with MA as he will advise best, he steered me away from the Bosch for my car TV8 said:
Hoover. said:
MPoxon said:
Yes I would be very interested to see the RR results. I am planning to get a session booked in with Mark Adams at TVR power to adjust the map to make the most of the plenum so I will keep you posted.
may be worth swapping the AFM for a larger one....just a thought as the 5AM is now a major bottle neck in your induction system... 20AM ??? best chat with MA as he will advise best, he steered me away from the Bosch for my car I already have the larger Bosch AFM, red top spray pattern Bosch injectors all mapped using the Tornado software. I wasn't aware Jules had branched out to 14CUX, I am familiar with his work with the Cerb MBE systems. Thanks for the recommendation but I will be sticking with Mark Adams for the time being. I have used Mark Adams for many years now, he fully understands my expectations and is familiar with the car having mapped it a number of times for various mods.
griffdude said:
Nice feature in Sprint Matthew. Got it on a rolling road yet to give any idea of power delivery?
Thank you very much Howard, glad you enjoyed it. The team at the TVRCC have done a really good job with the article, it looks great. Not as yet, I am booked in at TVR Power on the 24th June with Mark Adams. It will be interesting to see how the shape of the graphs have changed from last year. Mark reckons he may be able to get it to perform even better with a few tweaks to the fuelling to make use of the increased airflow.
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