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Jenvey ITB's and fuel regulators
Headrush - 21/3/07 at 10:51 AM

This is going to be my first post here so Hi !
I'm building an S2000 engined Dax Rush and have a quick question which I hope someone can help with.....

I've decided to run a set of Jenvey Individual Throttle Bodies as the original Honda inlet is a just too messy. Does anyone know whether you need a vacuum line connecting to the the fuel regulator when using ITB's and if so, which TB(s) would you take the vacuum from?
I have advised to run the fuel at 58PSI (4 bar) - do you think it would matter if it were held at that pressure from idle through to full load? I assume that the vacuum connector on regulators usually reduces fuel pressure at low loading.....


Agriv8 - 21/3/07 at 11:07 AM

Welcolm.

another DROC member ? .

I would think if you are using after market ECU you should not need it as the aftermarket ECU is lilkley compensate

if your using stock ecu dont know?

Chris m will be along in mo I am sure

regards

Agriv8


Headrush - 21/3/07 at 11:27 AM

I've gone along with the suggestion from John at RaceEnginedesign to use the RaceTech ECU which already has a copy of their autograss base map done for the s2000 on Jenvey TBs and a standard exhaust.
The interesting thing with the Jnvey TB's is that the Jenvey inlet manifold is 45mm whilst the actual TB and trumpets are 50mm so I need to taper the inlet manifold down somehow..... dremel and grinding stones I guess!


Headrush - 21/3/07 at 11:52 AM

I just spoke to the guys at R.E.D and they want £350 just to machine the inlets down to size for me.... ouch!


Confused but excited. - 21/3/07 at 02:48 PM

Couldn't you grind and polish it yourself? £350 is extracting the urine a bit.


zetec - 21/3/07 at 03:06 PM

As said the aftermarket ECU should look after all fueling on a normally aspirated engine. 4 bar is a little high, most run 3-3.5, check which injectors and their flow rate.

Have a look at Emerald ECUs very good aftermarket help and new version just out.


FlansS14 - 21/3/07 at 03:44 PM

Make sure you dry sump it or you'll get oil starvation and in case you didn't know you can't buy internals for that engine


Headrush - 21/3/07 at 04:09 PM

I'm not going to dry sump it just yet as the engine has just been rehoned and ringed so it wont be getting any abuse for a while!
I'm not too fussed about the engine going pop in all honesty as its only a couple of grand (max) for another from the scrappies.


dougal - 21/3/07 at 04:30 PM

The vac connection will be needed as it is used to compensate for the varying preasure in the inlet manifold. ie at full throttle the fuel will be at an absolute presasure of 4-5 bar (3-4 over atmos) and the inlet will be at 1bar -no vacume. it idol the fuel should still be at 4-5 but the manifold will be at around 0 (near total vacume) and would flow more.

normally an ecu would be programed without this conpensation so i would recomend connecting it.

on my TB's each throttle has a vacume take off after the throttle. i have connected these together which then go to the preasure reg and the map sensor.

p.s looked at your site and it looks like a nice project


rusty nuts - 21/3/07 at 07:02 PM

According to Dave Walker of Emerald you don't need to connect the regulator to any vacuum source as ECU if properly set up will compensate .


FlansS14 - 22/3/07 at 09:14 AM

quote:
Originally posted by Headrush
I'm not going to dry sump it just yet as the engine has just been rehoned and ringed so it wont be getting any abuse for a while!
I'm not too fussed about the engine going pop in all honesty as its only a couple of grand (max) for another from the scrappies.


lol a Few Grand... some people have too much money. Good luck with the project only when i ead into fitting this engine i was put off by this. Apparently the type7 kit car can turn allot harder than the s2000 which has caused starvation on a few installs. just so you have a heads up


Headrush - 5/4/07 at 02:31 PM

I had the S2000 block rehoned, new rings and shells fitted and valves lapped in so its not that impossible to get basic parts - however some parts are Honda supplied only, such as the shells which you often find use different journal sizes on the same S2K crank. Not sure about sourcing more fundamental engine parts, but its rarely cost effective to go to this level of rebuild.


MikeRJ - 5/4/07 at 04:26 PM

quote:
Originally posted by rusty nuts
According to Dave Walker of Emerald you don't need to connect the regulator to any vacuum source as ECU if properly set up will compensate .


Yep, many modified engines running aftermarket ECU's don't bother with the vacuum connection. As long as your injectors are suitably sized the ECU can compensate.

Note that the Megasquirt VE table generator assumes you are using a vacuum(or boost) compensated regulator. I know the OP isn't using this system but someone may need to know that at some stage.