too weak on boost

[zen]

ok..

running m112 on gen 2 uz.8psi max.

standard ecu and injectors..in tank range rover fuel pump (its in a range rover)

when cold no problems,a/r meter shows good ratios,but once warm terrible on boost (ie keep it off)
it seems to be when on first toes it,bogs down,stutters then catches up..defo..lack of fuel..

has after market fuel regulator fitted..

is fitted with lpg (propane) which it is fine on..plenty fuel..(goes like a rocket)

now what can i do to improve things,i dont really want to add aftermarket ecu yet as skint!!(but am aware i may have too)

what puzzles me is its fine on cold so i assume there must be fuel there,so not injectors need sizing up or lack of fuel pressure etc...

no fault codes other than secondary o2 sensors (not fitted)

thanks

 

[LP1]

Bog on boost

I'm running a M112 on a 95 SC, stock ecu but with 315cc injectors. I have a slight bog with light throttle and low boost. I've learned just to give it more throttle and everyone is happy. We are also running the same set up on a 92 and it bogs as well. I just bought a Zietronix ZT-2 to try and figure out the issue. Not sure when I'll have some data but I'll post the results. BTW the 315cc are at 78% duty cycle at WOT, you got to be close on running out of fuel at max boost.

 

[spf_lexus]

LP1:

Light throttle bog is more than likely from the stock ecu + 315cc's. I would throw a wideband on it and i would be willing to bet its super rich until you step on it, effectively bringing the AFR from a super rich state to a more managable level. also, if your pushing any more than 6psi, your really gambling that the rods dont snap. 1994.5 and older are the UZ's with the beefy rods. Anything newer have the notoriously weak rods.

ZEN:

when its cold, the ecu will dump more fuel to warm up the cats and once warm, duty cycle may drop, and so will fuel supply. You might want to add a rising rate regulator with 12:1 ratio to give it a bit more go juice. Whats the wideband say when its warm and under boost?

 

[Cobber]

Sounds to me like you are loosing boost, possibly through the idle speed control. Post up a picture of the set up.

 

[sideshow]

get a rising rate fuel presure reg this will richen the mixtures up when on boost
its a dodgey way but seems thats how most people like it hehehe

 

[sideshow]

u can also put a resistor in on the coolant temp sensor to replicate it being cold
and unplug the std sensor
this would make the ecu think its cold all the time

 

[XR8tt]

Maybe fit a Walbro 255 in tank pump with rising rate reg ??
As the fuel pressure increases you need a good pump to keep the flow required..
Maybe close plug gaps alittle ???

 

[stevechumo]

All of the above seem like good suggestions.

 

[XR8tt]

Try one of these at around 50/50 water / meth..
It may save your engine...
http://www.coolingmist.com/
Another..
Nitrous Express and Snow Performance
again..Just google water meth kits..

The addition of methanol is to add more fuel..
Keeps detonation at bay which is an issue with untuned forced induction engines..
Try some colder plugs and close gaps to .80mm...Or so...