plenum and vaccum hose design for individual runners

[dr.occa]

here's a vacuum reservoir i made out of 2" pvc piping and end caps.


the good things about it are:
1. inexpensive
2. easy to cut to necessary size
3. easy to drill
4. no need to thread the holes: just screw in your fittings (the material is soft enough that you don't even need to apply any thread tape)

[Salamander]

Good job. Shock gas!.

Where download this program "RT Analysis" is work with TPS?

[matnrach]

The program is from Race Technology and uses no sensors from the MJLJ. It uses a TPS attached to the carb spindle and a remote pressure sensor all logged at 100hz. Also has an input from the coil for engine speed (at the time this was logged before installing the MJLJ - now I use the coil input wire and configure the software as an 8 cylinder engine)

Details are here:http://www.race-technology.com/dl1_2_27.html

Pic shows some of the installation

[Salamander]

Hello, Matnrach.

Where you live? I would like to have these blue for the coolant hoses, where can I get or buy?
Please send me an MP

[retal052]

Hey guys first post!!

I have a Yamaha yzf-R6 throttlebody injection setup on my A14 datsun engine. The haltech F7 computer uses a tps/map system. When I attached the suggested mini plenum I lost all throttle response and it backfires. I am not running the MJLJ yet. I will attach it this weekend and see how we go!

If you need a mini plenum to smooth out the pulses, why do I loose response when I attach the plenum??

[matnrach]

If you are using an injection setup then the ecu then there could be a few reasons
1. The plenum slightly delays the change in pressure seen when you apply throttle so you need to chane the transient fuelling parameters but I doubt that would be the reason.
2. It is leaking
3 . It is connected post throttle to the average of all 4 cylinders?
Really there should be no issue with using a plenum of this size the dampen the intake port pressure.
As you can see from the logs all it does is reduce the peak to peak instantaneous pressure.

[retal052]

should I mount the plenum before all accessories? eg. Fuel reg, ecu, mjlj/dizzy the plenum is a genuine nissan off a 180sx. Or only before the mjlj? The cannister I have is 2x4inch

[matnrach]

Yor canister is either 200cc or 400cc depending if it is 2in dia or 4in diameter.
I would say this is too big and would delay any pressure signal from a change in throttle. My damper is around 60cc and suffers very little delay.
better to connect it straight to the plenum directly (via a small diameter pipe)

[Dave999]

anyone thought of using one of these

http://www.dellorto.co.uk/merchandise/p ... ctionID=71



its a alfaromeo part designed to smooth pulses in vacuum when running 2 dellorto dhla on a 1500 or 1600 alfa boxer engine with the vacuum advance for the disributor plumbed into a ported (above the butterfly) tube on one barrel of the carb

dave

[krusher74]

I dont know the physics of the difference if you used 3 T's to get your 4 vac lines down to one or went from 4 to 1, but I found a 5way T, so you can go from 4 to 1
http://www.imperialinc.com/items.asp?item=0373590

[NickVyse]

Hi - first question about MAP plumbling as I'm about to switch to twin dellortos on a BMW s14 engine and have the decision to make re TPS or MAP. So question is, and it might be a stupid one, but would equal length pipes be beneficial prior to them joinging the dampening reservoir? As I'm writing this I'm starting to think 'no', and that one connecting pipe with T pieces would work just the same as it's about pressure and not flow, but I'll put it out there anyway.

[brentp]

Hello,

Overall I would say the length of the individual hoses isn't critical since the reservoir is averaging out the pulses.