tb42e turbo petrol + lpg

[naif]

hey guys.

currently putting the turbo onto my tb42e but am having problems with it not idling and just sitting there reving between 1750rpm and 2000rpm constantly.

i am ondering where you others with the efi models have plumbed the aacv(idle control) hose into? pre or post turbo.

cheers, Nathan

[hiy6o]

Mines in post turbo , no probs.

[naif]

hey mate, ive read a few of your posts and in one you said you where running a t3/t4 ith a .6# exhaust housing, did this cause you any problems?

im wondering where ive gone wrong, cant seem to make it idle happily.

im running an older model gas research carby, and am using a subaru tps which reads the opposite of the patrol one, to combat the problem of the reversed throttle.

ive backed the distributer timing adjustment off as far as it can go but still it will idle at 1300rpm. te rest of the ignition system is stock nissan.

[naif]

allright, after some testing it seems the gas research throttle body i purchased second hand isnt sealing and is allowing air to be drawn thru the butterfly, rang gas research and theres a back log and might not get a new one until next year

what size gas research throttle bodys are people running on there tb42 turbos? the guy said he cant offer advice on turbo applications.

[mooseboost]

Hi Mate,

I'm running an S350 Throttle Body on 12psi, one covertor.

[hiy6o]

hey mate , no gas on mine , changed the turbo to get more go out of it now running GT3076 ball bearing turbo with custom high mount manifold 1.08a/r from memory ( been on there for a while now) buy ran Ok on the T3T4 one at the time.

[toddcuth]

hey mate , no gas on mine , changed the turbo to get more go out of it now running GT3076 ball bearing turbo with custom high mount manifold 1.08a/r from memory ( been on there for a while now) buy ran Ok on the T3T4 one at the time.

Hi sorry to hijack but when does yours come on boost and does it run out???

[chpd80]

Joel from PGS in Melbourne has lots of experience with the gas research and turbo setups, If he cant help you no-one can.

[hiy6o]

Hey toddcuth is on 13psi at about 2700 through to 5750 rev limited very happy with the new set up

[naif]

well ive ditched the lpg for now, until the new year when i start back at work and can get a new gas research throttle body.

cars going pretty good now with the factory throttle body, turbo seems to be a good size as its making around 7psi in 5th at 100, which will be great for towing,

also halved the 80 - 100km/h in 5th too

now to fix the exhaust leaks and fit some different hose clamps to stop the cooler piping blowing off.

[chpd80]

If you can weld the intercooler pipes, then a couple of small welds near the edge will stop them blowing off.
I'm surprised anything is blowing off at 7 pound though !!!!!!!!!!
Have you verified that it IS 7 pound ?????

[PGS 4WD]

A common problem with the Gasresearch carby when backfired often enough is that the butterfly blade bends, it can usually be removed and straightened, the carby timing, as to where the main metering opens relative to the blade is critical and needs to be set right on reassembly. Typical symptoms are high idle, LPG smell (running rich) sometime flat spots around part throttle. I can straighten the blade and reset the timing if you want, we are back on the 5th. Gasresearch is always backlogged. This wasn't the case 10 years ago when I was workshop foreman at Gasresearch. Sad but true, the new owners are not as enthusiastic about the product as the origional developers, Leigh Sharples and Steve Malone.

Joel

[toy77]

hi Naif,

so you are running your injected tb42 on straight petrol at the moment with the turbo?

Are you running an aftermarket comp or factory? any other changes?

Cheers
Stew

[naif]

hi Naif,

so you are running your injected tb42 on straight petrol at the moment with the turbo?

Are you running an aftermarket comp or factory? any other changes?

Cheers
Stew

yeah straight petrol at the moment, new gas research b2 gas converter still in place, but have pulled the fuse out for the gas solenoids.

yeah im still running the factory computer, plans are to get a nistune daughterboard to make the stock ecu fully programmable using the nissan data cable which i have.

monitoring afr's using my innovate lc-1 wideband controller, still yet to figure out why it ran like shit with the narrowband outputting from the lc-1 to the factory ecu prior to turbo.

its running a brand new rage bigboar 3" exhaust for a td42t which actually clears the gas tank perfectly ($420 from scotts rods on ebay)

everything else is basically stock except for the home made manifold and dump pipe.

[chpd80]

Geez mate, must be pinging like a bitch under boost with the standard ecu.

[naif]

nope no pinging, i dont rev it higher then 3k very often,

its an afm based ecu, therefore fuel is governed by how much air is being drawn into the engine, on boost the leanest mixtures ive seen are 13.2.

i still havent regapped the plugs so there still 1.1 and it hasnt missed on boost.

forgot to note its running a new walbro 255l/h fuelpump.

[Jimbo]

Have you got any pics of the setup?

What other dramas did you run into?

[naif]

only real dramas have been with the gas setup and the oil feed line,

the one that came with the turbo had an alloy block that bolted to the top of the turbo, the thread snapped off, so got fittings from pirtek which then the fitting on the end of the oil line decided to push out as i did up the thread so had a new fitting put on by pirtek.

only other thing was the gas supplier gave me boc argonsheild universal, even tho i was tig welding (newbi tig welder) when the gas should have been pure argon.

its really transformed the car,

am currently having trouble with the usb - serial converter for the innovate lc-1, which was wrking a few weeks ago, so i cant connect it to the laptop.

when this is fixed i will do a log of afr vs rpm.

also need to do a run with the laptop connected to the ecu and check when the injectors and airflow meter max out.

[naif]

quick picture, its all ive got on the pc at themoment



pod filter and the subaru WAIC will most likely be temporary,

need to clean up the piping and wiring.

its running alot better now, running 8psi, makes boost from around 1750rpm.

[toy77]

looking good...

How is it running now??

Cheers
Stew

[PGS 4WD]

nope no pinging, i dont rev it higher then 3k very often,

its an afm based ecu, therefore fuel is governed by how much air is being drawn into the engine, on boost the leanest mixtures ive seen are 13.2.

i still havent regapped the plugs so there still 1.1 and it hasnt missed on boost.

forgot to note its running a new walbro 255l/h fuelpump.

Depending of course on the amount of boost but 13.2:1 is too lean, that is N/A mixture and lean at that!
Did you rectify the high idle, some of the Gasresearch carbies don't seal so well around the blade when closed and need a little adjustment.
Allthough you are correct it has an Air flow meter, it only works until it is maxed out, which it will, they are designed to work with the air flow of the engine and will usually max out meanaing the ECU can only run what it knows for the maximum Air flow value, a potentially dangerous arrangement if maximum air flow is acheived under boost at 3000 rpm and you start reving it to 5000 rpm. Not to mention if you still have stock injectors that will hit the wall and cause lean out. Treat it with respect or it will fail.

Joel

[naif]

yeah i know 13.2 is too lean on petrol under boost, its usually in the low 12's,
i know its running lean and am driving it accordingly and monitoring the wideband guage.
still drives alot better off boost then it ever did before, the impco 200's must put a huge restrictionon the intake.

i havent reved the engine out, and dont plan to until i get the nistune chip and add some fuel and whatever else needs doing.

interesting thing is that the patrols ecu actually has fuel and timing knock maps, but no knock sensor, ive compared the wiring diagram to others and the one used for the knock sensor on ecu's with almost identical pinouts isnt used on the patrol ecu.

nah i never got the gas research throttle body running proply, sanded down the butterfly with super fine wet and dry to get it sealing best i could but there was still slight gaps around the edges.

i got the idle to where it should be on petrol by adjusting the screw on the it would rev on gas butwouldnt idle no matter what i did.

so for now ive gone back to the standard nissan throttlebody and am just running it on petrol, will get a new GRA throttlebody sometime.

[PGS 4WD]

They are a trick to setup on Gasresearch, it requires a vapour feed into the fast idle at the rear of the manifold that can be jetted or it will never acheive the same idle speed or quality as petrol.
These ECU's are somewhat generic, JECS? Hanve Nistune got that softed now, last I looked they were only doing the eprom vehicles not the eeprom flash type. Must look into it as was considering buying the software. I'm still a fan of a plug in aftermarket though for the extras like boost control.

Joel

[naif]

They are a trick to setup on Gasresearch, it requires a vapour feed into the fast idle at the rear of the manifold that can be jetted or it will never acheive the same idle speed or quality as petrol.
These ECU's are somewhat generic, JECS? Hanve Nistune got that softed now, last I looked they were only doing the eprom vehicles not the eeprom flash type. Must look into it as was considering buying the software. I'm still a fan of a plug in aftermarket though for the extras like boost control.

Joel

the TB42E is a hitachi ecu, well atleast mine is.

nistune do realtime daugterboards for many different nissan vehicles now. but someare still under development.
the software has all the address's for the TB42E, all maps, data, scalers, sensors, revlimiter can be changed.

the software has some pretty cool features, like resize injectors, maf sensor, afr auto adjust, wideband input tracer (it can use variouse different wideband units, my innovate lc1 is one of them), afr grapher(afr vs rpm) as well as full consult data support.

[PGS 4WD]

Yes I have HP tuners, SCT, EFI live and most aftermarket stuff as well as older Holden VN-VS stuff, what you can do is astounding these days.

[turbmav]

Hey just a quick question Guy's, if 13's are too lean on petrol than 12's would be to lean on a boosted lpg engine right?

[naif]

Hey just a quick question Guy's, if 13's are too lean on petrol than 12's would be to lean on a boosted lpg engine right?

with petrol under boost you usually aim for between 11 - 12

lpg reads at a leaner ratio

stoich for petrol is 14.7 whereas lpg from memory is 15.5

so under boost on lpg you would aim for a 12 - 13 ratio(pretty sure the forced induction papers that i got from gas research said 13)

PGS will be able to confirm if im right or wrong

[PGS 4WD]

Hey just a quick question Guy's, if 13's are too lean on petrol than 12's would be to lean on a boosted lpg engine right?

with petrol under boost you usually aim for between 11 - 12

lpg reads at a leaner ratio

stoich for petrol is 14.7 whereas lpg from memory is 15.5

so under boost on lpg you would aim for a 12 - 13 ratio(pretty sure the forced induction papers that i got from gas research said 13)

PGS will be able to confirm if im right or wrong

Its easier in Lambda, around 0.82 Lambda which when you calculate 15.5x0.82 = 12.71 for LPG or 14.7x0.82 = 12.08 for petrol, but this is only a guide, I consider vehicle weight, application, timing and other factors in setting the correct mixture.

[51nrr]

nope no pinging, i dont rev it higher then 3k very often,

its an afm based ecu, therefore fuel is governed by how much air is being drawn into the engine, on boost the leanest mixtures ive seen are 13.2.

i still havent regapped the plugs so there still 1.1 and it hasnt missed on boost.

forgot to note its running a new walbro 255l/h fuelpump.

hey mate i've just done the turbo converstion on my TB42E and it pinged its head off but was advised to put a better fuel pump on so i got a VL turbo one. i was wondering when you put the walbro on did you have to get a fuel pressure reg and raise the pressure in the fuel rail?

[naif]

nope no pinging, i dont rev it higher then 3k very often,

its an afm based ecu, therefore fuel is governed by how much air is being drawn into the engine, on boost the leanest mixtures ive seen are 13.2.

i still havent regapped the plugs so there still 1.1 and it hasnt missed on boost.

forgot to note its running a new walbro 255l/h fuelpump.

hey mate i've just done the turbo converstion on my TB42E and it pinged its head off but was advised to put a better fuel pump on so i got a VL turbo one. i was wondering when you put the walbro on did you have to get a fuel pressure reg and raise the pressure in the fuel rail?

hey mate, im running a wideband air/fuel meter and guage so i havent allowed it to get lean enough to ping as im constantly monitoring afr's.

i have been driving it in a safe way and control boost with the throttle so as i dont go over 4psi anything more and it starts to lean out in a bad way.

i havent installed an aftermarket FPR, installing one and raising the base fuel pressure can work, the problem is when you increase the fuel pressure, it increases over the whole range so it will run extremely rich off boost.

according to a tuner from another forum im on, a solution to this is to use a malpassis 1.7:1 FPR, apposed to a 1:1 FPR, what this does is increases fuel pressure 1.7psi to every 1 psi of boost.

http://cgi.ebay.com.au/MALPASSI-TURBO-R ... 563a9b5e12

at the moment ive unsoldered the factory eprom from the ecu and have installed a socket, which allows me to modify the ecu data, write it to another eprom and put it in the socket.

i still plan to go the nistune board and get the gas running when funds permit.

perhaps ring some tuning shops in qld and ask if they do emulator tuning for nissans.