TRX1 carb tuning Q & A.. could use some, or a LOT of help

[Wheel House Motorsports]

specs
2003 rx1 motor
stm carb caps and the billet T's
powderlites headshim and cam timing mod
custom 4-1 sidemount header
mitsubishi evo III 16g turbo, the bigest of em all
no intercooler, but my charge tube is a 5" pipe that goes from turbo outlest up to airbox size, so more just a size adapter then a tube.
exhaust side on the turbo is a tad tight, so thats why my boost numbers come up SO fast, dont worry wastegate is like a freakin manhole so there wont be any restriction issues, double downpipe into 3" tunnel dump behind chaincase.

elevation of riding is 6k+ right now, may come down to 4-5k mid winter sometimes.

jetting is 130 mains 75, 17.5 and 2 turns out, so what most run. the issue i am having is my float bowl reference line, i have 2 fittings i can pull from to provide a signal, just seems that it works bizzarely.

i have a 3/8" hose barb tapped into the turbo outlet, no it doesnt leak, and one right in the inlet of the airbox and the air comes in at an angle and hits the thing almost straight on, so both should be getting an amazing signal. with fuel pressure set at 4# at idle referenced from the carb boots the thing starts awsome, afr readings are --- super lean but as soon as i even tension the 1/8" slack in the throttle cable it drops right back to where it should be, no bumping the idle up doesnt make it go away, thats weird for me. I got to do some on snow testing today and heres what happened. idle if i hit WOT the thing might rev say to engagement and as soon as the belt grabbed, lean pops and dies, half throttle it blasts up really fast and hits maybe 6k and is building boost and then lean pops, or i can ease on it and not build boost and keep my afr at around 12-13 and puts around, if i even go barely to hard on it at all the thing just lean pops and i back out of it as its not good for it. fuel pressure rises awsome with boost, its perfect, it seems much like a reference and possible a jetting issue from what I did today.

When I just try to run the line straight off the airbox to the float bowls the thing instantly falls on its face as soon as you touch the throttle more then enough ot pull from 1500 idle up to say 2200. if i run staright off the turbo outlet to the float bowls the thing dies as soon as you even touch the throttle, and when i say dies, it doesnt stall, it just pops and will stall if you dont let off the thing. if I T the two lines together off the airbox and the turbo and run them to the float bowls it runs alright and you can milk it around like i was talking about last paragraph, BUT, it runs better if the line from the turbo is ziptied kinked, so its almost like its all airbox signal, so then it runs halfway enough to blast around, and you can run more then no throttle from idle.

my 3 thoughts are, because i have no intercooler, am I not seeing enough pressure loss from turbo outlet to carb boots to get a strong enough pressure gain to run stock jetting, as normally, the really strong signal in the pitot tube is way more then that after the intercooler. second idea is that my gauge reads so lean at idle, it might be rich popping when i get a super strong signal from my turbo outlet. my 3rd was my tps wires have a small ding in them right on the spot they go into the carbs and was curious what would happen if I was having TPS issues, just a thought as im not sure how it affects the RX1 motors, there on there for some reason.

it seems like jetting up wont just cure my problems as its as SOON as any amount of boost is made the thing fails misserably. im gonna check my billet t's and make sure i didnt brain fart those or something super trivial like that.

sorry for the long post, just trying to get as much info out as i can.

 

[tmbl52]

I run stock jetting without intercooler

 

[Wheel House Motorsports]

anymore info on your reference lines, where are they from.. what kinda afr.. just lookin for more info as thats good to here, but details are what i seek.

 

[tmbl52]

cant recite them from memory so i will have to go out to the garage and look

 

[tmbl52]

I have two 3/8 lines off the air box. One goes to the fuel regulator and one raises the carb slides and of course my pitot jet feeds extra fuel upon boost. My carb boots are hooked up to oem fuel pumps just in case electric pump goes down. I run my high low boost switch off the turbo compressor. afr reads 14 at idle.

 

[0007]

You need to strip the carbs apart and glue some stuff together
Why dont you talk to someone like leipheimer and get the old RX1 MCX instal instructions
What did you do with the 2 big hoses for slide vacuum

 

[Wheel House Motorsports]

the 2 vaccum slides are hooked up to 2 stubs i have coming off the airbox just like any of the other turbo airboxes i have seen made. I may call leipheimers tuesday, also, might be calling ted jannety as i got the carb caps and billet t's from him, and he seems to be super helpful on this stuff.

i shouldnt have to glue anything, i thought that was a baindaid mod for the plasitc t fitings for the float bowl pressure... hmm. or i could be smart and pressure test everything... and also hook my boost gauge into my pressure line going to the float bowls to see what on earth it does when it cuts out and dies.

 

[Wheel House Motorsports]

after doing some talking with people(tmbl52 and givemeaboost) it seems as thought a 3/8" reference line from the turbo might be just killing the motor when thats all i run... it idles alright, but as soon as the thing opens it stalls out... im going to try installing a jet as i guess 3/8" fuel line flows more air then a tiny 120 main jet.

more trial and error... ill see what happenes when i run the sled again tommorow.

 

[TTE]

PM your e-mail address and I will mail you the MCX and Bender RX-1 turbo install manuals

 

[Wheel House Motorsports]

I got ahold of both of those from elsewhere on the web already, but thanks a ton for the offer.

 

[sledfvr]

Mine popped bad when the carb boots were full of water. I don't think that would be the case with you unless you power washed it recently. You are going to want to silicone them to the valve cover though, otherwise they will leak. I think that's why the apex boots bolt on. Sounds more like you might have an electrical issue to me.

 

[Turbo Monster]

Where is you fuel pressure gauge.You should have it in a place that you can see it.That will give you an idea what is going on with your fuel pressure.When I had cracked my header it would run fine up to about quater throttleand back fire really bad..I took the hood off to watch my fuel pressure and it would only go to about 7 psi.So we knew something was wrong.At least if you can watch the fuel pressure gauge you will know if you are getting to much fuel or not enough.

 

[Wheel House Motorsports]

not fuel pressure issue, i have a gauge hooked into a port on the regulator and it sits right next to all my gauges, when the thing is seeing vaccum, idle, it sits at 4 pounds, you open the throttle, and go off vaccum and no boost fuel pressure jumps right up along with the boost gauge..

im thinking its my reference line needs a restrictor in it based of what i ahve been doing, as when i run a straight 3/8" line from my turbo housing the thing just dies as soon as it comes off idle like its just hammering the thing full of fuel. i have a way to run a variable restrictor inline with the reference thing, its jus a bleeder style boost controller, that way its like a needle and seat pitot tube setup, so i dont have to swap jets when going up in elevation or messing with boost, i can just adjust the flow to the float bowls.

does anyone have a picture of how the jets in the pitot tube setup works?

 

[Wheel House Motorsports]

i just did some reading up on inlet size on pitot tube, seems like the larger the inlet on it allows the thing to get more pressurized are results in more fuel being dumped in as the throttle is pushed and boost rolls on.

i read a guy who ran a 4mm inlet hole and only ran 100 main jets at elevation, im running 130's and had a 3/8" line meaning my hole is about 6x the area of his hole i would have been getting a LOT of fuel with the straight line, i am ver confident that if i restrict it down its gonna work a lot better, at least get me closer.

 

[Wheel House Motorsports]

i tried a restriced line, no luck, i made a cracked out pitot type tube by running 3/16" copper line down into the airboc through my extra reference port... angled it into incoming air and then put hooked that to the float bowls via the reference line i had. this did absolutely nothing, still runs like dog pooooo.

i would like to try out a different pressure regulator as mine has a different spring in it and am wondering if that is causing me this retarted issue.. I just want to be able to knock things off the list of i know it works.

 

[Wheel House Motorsports]

well, ill keep up the talking to myself.... im wondering because my reference lines for my carb slides dont get a good boost signal if they arent opening properly and therefor causing me massive fueling issues? im gonna try to route them to a stronger signal and see what the sled has to say about that.

 

[heinracing]

i have a rx1 intercooler for sale if you ever want to change your design a bit

 

[Wheel House Motorsports]

hein, well have to talk on that as i will see what you got and what i can do with it!

so i hooked my carb slides to a good reference line that gets much more boost pressure then the stubs on my airbox.. I actually get air fuel reading at idle... actually its almost a tad high, sits right around 14 when its warmed up.. 13.5 when it starts to get really hot running in the garage, this doesnt seem to cure my boosted lean out, i have 2 days off school to work on the pig, i may try to throw a new set of mains in that are WAY bigger and see if that helps, i know you can theoretically run stock jetting, but thats with the larger pressure signal pre intercooler and all. i think i just may need bigger jets, cheap demo to see what on earth happens, see if its the right direction.

 

[BigFish BC]

if it were a tors or tps issue it would not let you above 2500rpm it will just pop like a lean pop.what is your af doing is it going right to 16.0 or what.your not hitting your revlimiter are you it will pop bad.is your fuel pump working proper.
just a few things to look at.

 

[Turbo11T]

Bender

I believe that the original stage 1 bender kit didn't run a intercooler. Should not be hard to get a signal that will get you close enough to run up in rpm's. From what I know turbo motors will rev being pretty rich even, it is when you get off the throttle that you see i problem with richness.

I think you have other problems. I am wondering if this would even rev without the turbo? Also how sure are you that your cam timing is perfect now? I know we went over this before but have you been into the carbs to clean them? Since you said the sled was having issues prior to being turboed I think Everything in the carbs needs to be disassembled, cleaned properly, and reassembled and set to factory specs as far as turns on fuel screws,jets, needles, etc.

Also do a leak down test on everything. This will tell you if you have a bad leak somewhere.

It is a bit of work. But in the end you know your not chasing your tail. Starting with a motor with tuning problems is never good. Trust me been there. It will make a guy go crazy! Just remember that we all want to see this thing run. So step back take some time and eliminate things. Dont mean to come off as a jerk. It just seems as though your skirting around the things that i would check first.