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Who's got Jenveys ? (or PMO ITBs)


MonkeyChap

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Hello,

I've been chatting to a few of the usual suspect Porsche engine builders, and reading a few threads here and there. One comment I heard a couple of times is that Jenveys aren't built as a complete unit so there is potential for the throttle linkage to stick if the bodies get out of alignment. I also heard a couple of -ve comments about PMOs not offering a direct air route on the rear two cylinders (not sure this makes a huge difference with ITBs though).

Has anyone here had problems with Jenveys (or PMOs for that matter) ?

Ta

Ian

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Speaking to Chris Flavell at Fenn Lane last week - they are working on a straightforward ITB bolt on for 911s.

 

Not yet available but worth speaking to them if you are thinking of going down that route.

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Not sure what Neil does - I left a message with one of his colleagues about just this topic. It was Chris who originally pointed out the potential linkage issue, and I understand that's one of the reasons why Nick Fulljames prefers PMOs. CANEMS seem to like Jenveys though. I had no idea Singer used them - it looks to me like they've got a plenum system off a later water cooled Porsche on most of the Singer engines I've seen. I can't think why you'd stick that on top of throttle bodies ?

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Yes, they have a GT3 plenum over ITBs. This is exactly what Porsche race engines do as well. I think the first was the 964 RSR - 3.8 litres and 350hp thru a tiny inlet restrictor. You get the resonance tuning from variable inlet tract lengths and you get the instant throttle response and less restrictive path for the inlet charge that ITBs give. Cake and eating it.

 

9M certainly used Jenveys at the outset and they built the first Singer engines before it moved to Cosworth. Same thing that Rothsport does with Jenveys and late plenums now that I think about it. Fairly sure the 9M ITBs are rebranded Jenveys, maybe modified a bit.

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Its the engine management system that drives your choice for mapping. Lots know Motec and will work with it while fewer will work with lesser known/used ECUs. Wayne Schofield works with all sorts (not everything though) and is very good, but tough to get hold of etc.

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MoTec looks to be very expensive compared to many others which offer much the same functionality. Emerald/Canems/Megasquirt, etc should all be more than capable of running the fuelling side and the ignition if I choose at a later date.

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Did you not read RB's post? Motec works and people know it and can work with it. No point having a cheap system that only 1 person can work with and you are miles from them.

 

:twocents: ( and alcohol fuelled ) :)

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If you search 9m posts on rennlist re ITBs, Colin has stated that ITBs aren't warranted for cars where peak power is <7k rpm. Rothsports setup with low butterfly and common plenum (similar to singer?) is meant to deliver throughout the range.

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  • 2 weeks later...

I'm in the process of installing a DTA S80 pro to my SC with ITBs. If you havent decided on which ECU to go for take a look at the DTA. I will be mapping mine using dual widebands so could let you have a very good file, as long as you engine spec is the same that is.

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  • 5 years later...
On 18/01/2016 at 21:03, alastair said:

Speaking to Chris Flavell at Fenn Lane last week - they are working on a straightforward ITB bolt on for 911s.

 

Not yet available but worth speaking to them if you are thinking of going down that route.

Well Chris never got the project finished after I left, and after he passed away I inherited the project from a mutual customer.

I'm please to say that after new pattern equipment has been made, coupled with a Canems ecu I have a running system, using tall 911R manifolds, with injector bosses in the base, and Weber pattern 100mm tall throttle bodies on top.

 

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  • 1 year later...
On 15/09/2021 at 20:14, 911retrim said:

Well Chris never got the project finished after I left, and after he passed away I inherited the project from a mutual customer.

I'm please to say that after new pattern equipment has been made, coupled with a Canems ecu I have a running system, using tall 911R manifolds, with injector bosses in the base, and Weber pattern 100mm tall throttle bodies on top.

 

@911retrim how did this work out in the end? 

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