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Jenvey DTH throttle bodies on 420R?


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I have a factory standard 420R SV

I am soon to have a bespoke ECU remap done by 'the two Steves', primarily to reduce kangarooing and improve drivability. I am told their remap usually results in a modest performance improvement also. 

My question is about what experience people have had when moving to Jenvey DTH throttle bodies - do they enhance drivability over the standard single butterfly plenum setup, or is it just better noise and an extra 10bhp?

Has anyone run into noise problems (black flags) on track after fitting Jenveys, where previously they were fine with noise

I'm asking about Jenveys before the ECU map as don't want to have to do another bespoke map after this one if I switch to Jenveys at a later date, best decide on Jenveys now and just get it mapped properly once! 



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I just completed a 420R SV build but swapped the standard engine for a 2.4L Duratec with Jenveys.  Although you didn't ask about fitment, I discovered the hard way that it does require some other changes to bolt on to the current models.  I'll share those in case that is news to you too.  None of these are difficult but they do require other parts.

  • The factory belt tensioner fouls the Jenvey's throttle shaft, and of course the TPS if you mount it to that side rather than the firewall end.  The fix is to use the manual tensioner available from Raceline, and possibly others, which in turn requires a shorter belt.  
  • The Jenvey throttle linkage fouls the upper radiator hose.  I had to fabricate a new hose run to work around this and ensure the two would never touch.  There may be other throttle linkages available that won't have this issue but I already had the Jenvey linkage so didn't pursue other options.  

Hopefully others can chime in to answer the questions you actually asked  :)


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  • 1 year later...

I’m considering DIY-fitting Jenveys to my 420-spec 2.0 Duratec (followed by having it professionally mapped/tuned).  (It’ll include a new unlocked MBE 9M4 ECU).

I’ve seen a few specific tips spread across lots of threads (including this one) but can’t locate a more detailed comprehensive set of install instructions or blog - including things like throttle cable routing options, linkage orientation & mounting options, fitting head blanks, TPS connection, fuel line connection, new injector connections, plumbing alterations etc. 

I think I’ve searched every corner of the internet (without success), but hoping someone on BC can prove me wrong.



(2015 SuperSport R, with 420 cam upgrade, blue injectors, locked 992 ECU)

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My Duratec rebuild thread has a fair amount on throttle linkage, blank position (depends on injectors used), injector adapters, etc, page 7 onwards, here: https://www.caterhamlotus7.club/forums/topic/272933-tear-down-and-rebuild-of-my-r400-duratec-engine/page/7/

In summary on your points:

- If using the standard plate Jenvey filter backing plate, the linkage position may be determined for you, under is the default, but may interfere with components.

- If you use the Bosch "green" injectors, you will need to go in-head and blank the throttle body ports, they are also EV1 style with MiniTimer plugs as opposed to the standard EV6 injectors with USCAR plugs. I bought some adapters, but you can always buy the replacement R500 sub-loom from Caterham.

- You will need to choose the throttle body size, I went with 48mm, but stock 420R power would favour 45mm for torque presevation, highest power if going with other major changes would favour 50mm.

- The standard Jenvey mini Econoseal TPS connector is not compatible with the Caterham Econoseal one, I cut off the Jenvey one and replaced with a matching one to the Caterham loom

- Can't help you with the throttle cable routing, as my car is LHD

- If you are using the Bosch "green" injectors in the head, the standard fuel rail can be used with the same fuel line

- I had some clearance issues with the filter backing plate and the main radiator hose beneath it, solved by shortening the hose a small amount and moving it towards the engine a bit

- You will need to determine trumpet length (I went with 90mm) which will determine the filter depth used, you will then need to cut a bonnet hole if it is an S3 (optional on SV), my engine replacement thread details an accurate method to do this.


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Great list above.  One difference with my installation was to replace the connector on the loom to match version used on the Colvern.  This makes future TPS changes plug and play with no extra work.  Given I've had them fail in the past and have also swapped them out when troubleshooting, I wanted to optimize for that scenario.  If you don't want to cut the factory loom, another option is to make a short adapter.

When installing the injector plugs, drop them in the freezer the day before.  As an added measure, I also used Loctite 648 which is designed for tight fitting slip joints and maintains break away strength at high temps better than the similar Loctite 680.  The plugs in my other Duratec were fit without any sealant and have never budged, so the Loctite may be overkill rather than strictly necessary.

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