straight gas turbo

[benji.]

any info appreciated.....
ive got a 90 model sierra on straight gas with the ring just before the hat
on the carby, the way i see it i could cut the intake manifold off at the runners fab up a plenum chamber slap on a throttle body insert gas ring infront of t/b and blow the boost in. i understand i probly couldnt take it to far before doing something with the dizzy and more than likely valve springs..... please stop me if im right of track here, but its just a thought
that keeps poping up. cheers

[MightyMouse]

It sounds like its a traditional "draw through" gas system.....if so its not going to like boost without work.

Put the gas system before the turbo. TBody can go there also if its convenient.

[mrRocky]

If you run an intercooler with the gas system before the turbo and the car backfires then the intercooler will explode

[benji.]

cheers for reply mm sound like a good idea.
point taken mr rocky, not something you would want to chance....

[11_evl]

id like info as well as its something id like to do ..

MM is correct. the way you described it with the ring near the manifold after the turbo wont work without converter mods, i have thought of this option, as the BOOST pressure will overcome the gas 'flow' as its normally 'drawn' into the manifold.
im guessing you could mod the converter where the atmos port is and apply boost to that which will enrichen as boost comes on but ratios will be all over the shop...

for an easy way i was thinking of using a carbon seal turbo found on carby turbo sigmas and running the LPG thru that.

[badger]

use a Gas Research Australia (GRA) throttle body they are designed for turbo applications and easy to set up


edit
i found this on egay
http://cgi.ebay.com.au/GAS-RESEARCH-THR ... 439f50031a

[offroader-rama]

as badger said gas research they love boost and only give the gas that is needed use a GRA 350 cfm thats there smallest also i would adapt it to a injected manifold minus the throttle body as the gas research has its own.
I am looking for a g16b block and bottom end for the above project but will be supercharged not turbo.

[gladstone dave]

I had a twin turbo 1ggte straight 6cyl in a hilux running a suck though straight gas system, used impco mixers and ran a boost line to the convertor to even out the supply pressure/boost pressure. Never had a problem with that system in 3 yrs & about 70,000 klms with plenty of rough 4x4ing in that time. some suggest lag as a possible problem but I can say from experience that it wasn't. I also ran an intercooler for a while and did have 3 or 4 backfires in it's time but never had an explosion...... it is wise to run a burst valve of some sort tho just in case

[benji.]

glady dave, you say it was suck through???? as in the gas ring was before the turbo ??? was it necessary to run boost line to converter in this setup ??

[gladstone dave]

Yeah, I'll find some old pics tonight to try putting up.

[benji.]

cheers dave that would be great.

[PJ.zook]

Benji, if you are only going to be running low boost, just go with the basic setup. Use the original inlet manifold and bolt up an Impco 225 mixer with a throttle body of some description, use youre existing converter (assuming its a 'simple' not 'complex' converter), then whip up a basic log manifold with steampipe for the turbo manifold, bolt on turbo and set wastegate for like 3psi. You dont necessarily need to run an intercooler for low boost, but it helps.
You can use a GRA, many have gotten them to work nice, but many have not. I dont see why anyone would use them over the Impco anyway, as with the GRA they require setting up properly on a dyno to get em to work (unless someone who has done similar mods before you has done it before and given you the rods etc that you need), the Impco are almost bolt on and forget.

[gladstone dave]

Perfect Pj zook,

that is the best & easiest way in my opinion, no need to complicate something unnecesarily.

I'm still looking for some pics of my lux engine bay, they are here somewhere.........

[benji.]

Perfect Pj zook,

that is the best & easiest way in my opinion, no need to complicate something unnecesarily.

I'm still looking for some pics of my lux engine bay, they are here somewhere.........

pj, yes only after 4 or so pound to put some life back in the old girl and add soe tourqe. i was hoping to get away with the mixer ive got if possible
even if i just left the carb in place to meter the air, exaughst manifold isn t a worry it's the mixer im trying to sort out.... cooler im still a little unsure of like you said it isnt necessary and at the moment my radiator needs all the air it can get (she's see better days ) would probly knock up a small water to air hooked to a oil cooler or the like of to the side of the radiator with a fan. seems more logical as most of my 4 x 4 is at low speed so a air to air wouldn t be of much benfit.

here is some pics to give you an idea what ive got......... cheers

http://www.auszookers.com/index.php? name=Forums&file=viewtopic&t=11128

[11_evl]

is that duct tape?

[benji.]

is that duct tape?

sure is, nothing but the best money can buy

[benji.]

is that duct tape?

sure is, nothing but the best money can buy

[slyvan1]

i run a straight gas turbo setup. It is a 1.3 engine, i have a 225 impco mixer. it's intercooled. I have a de-comp plate in between my head and gasket. it runs 10 psi all day long. been running setup for 2 years. only drama is overheating up hills. it's not a daily driver.
being a long wheel base i have two gas tanks in the back witch hold 70 ltrs each. it'll do 4 days of driving in the bush, easily. its still fairly economical.i would prefer to have only one tank, but straight gas is a pain when u run out.

[Spike_Sierra]

You got pics slyvan1?

[slyvan1]

I'll try and get some photo's up. I'll have to figure out how to put them up. I

[slyvan1]

I made the turbo manifold out of a set of extractors that i had. The turbo is a ct12 of a twin turboed supra. thoughts were it was around about the right size. from that i run a 3inch exhaust. Just got the bends and mufflers then made the exhaust. not really many bends under a seirra. i put an oxy sensor in and an air fuel gauge, so that i can make sure it doesn't lean out.
Intercooler was an ebay special.
Throttle body was of a hyundai excel. it was the right size to mount up to the 225 mixer. It runs a B2 convertor. both mixer and convertor run alluminium covers instead of the plastic ones. There is a boost reference line to the convertor. when first set it up had to play around with springs in the convertor. having the oxy sensor in the exhaust made it easy to tune just doing road tests.
I haven't had it dyno'd but it seems to make good power. I've found that other mates with 1.3's rev there cars alot harder than i do or can. but this combo seems to make all its power between 3000rpm and 4000rpm. after that it just flattens out. it really driveable and with transfer and diff gears, theres basically no lag.

[PJ.zook]

Now THATS a backyard turbo job, good work!

[PGS 4WD]

The Gasresearch is brilliant BUT and its a big but, the carbies are really too big for anything under 1.6l, particularly on a blow through turbo they can be very difficult to tune well. Its all a bit technical but the air stalls and causes a lean out when you accelerate rapidly from low rpm, there is a state where the depression at the carby is equal to that on the converetr balance line and the converter can shut down. Larger engines will draw through the turbo prior to it spooling but little engines often will not, it is worst when the turbo size is on the large size. It is possible to sort of tune around this limitation with a compromise of overly rich mixtures under load.
It was a limitation that Gasresearch Australia was aware of when I worked for them and the smaller 270 cfm carby was developed in an attempt to remedy the problem.
Joel