Inlet Installation Improvements - help.

[Steven]

so this morning i'm driving to work after making great progress with tables and general running and starting. then the tube from the Intercooler to the Throttle body blows off. not a huge deal, i could 'v' band it as i did with the TB to Injection body, i could glue it on with something (hillbilly/redneck) or i could use it as an excuse to redesign it. i need some compliance as the engine moves around e.t.c. and i do need to move the aircleaner as i think that also causing me some problems.

I'm basically fishing for idea because i'm getting 'fed-up'

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[R100RT]

I take it that is on the "boost" side of things?
Regardless, standard connection practise on plumbing that has movement, is to leave a lip on the end of any and all tubes and utilize prevailing torque (or at least high strength) band clamps along with hose that has fabric weave or is designed for pressure and movement. You can weld a bead on the aluminum tubing or swage it in a rolling device (or shape with hammer and dollies for real old school workmanship). The clamp positions right next to the bead and once torqued makes it virtually impossible for the hose to release from it.

[WillExoIX]

You could always put a stud on either side of the coupler and use a zip tie or equivalent to hold them together then the coupler cant blow off.

Or do what R100RT sad and either put a bead on the end of the tubing. Or cut a notch all the way around the tube where the Tbolt clamp sits on the coupler.

Sent from my SCH-I535 using Tapatalk

[Steven]

Many Thanks, both good comments, the problem is as i keep improving the tune the boost gets higher. i may have to limit it somehow, i already have it so that the throttle peddle doesn't open the TB all the way (too much power...!). anyway i digress.

i was looking for redesign ideas and i think what i will do over winter is a bit of a 'cut and shut' where the TB gets moved closer to the inlet ports and the CAC to TB gets longer making compliance less of a problem. i currently have the injection (thing) 'v' clamped to the LS throttle body and i may just cut out the 'V' band and weld it direct.

I just pulled some better quality clamps out of the scrap bin to get me home. then i will look at putting a bead around the tubes this weekend.

now onto X Tao... different thread.

[Hahns5.2]

T-bolt clamps are the way to go for boost, hose clamps will simply not cut it. Also a "humped" silicone coupler is probably what you seek to handle the movement.

Aside from that, that thing must be a tuning nightmare, injectors are way upstream of the ports, and your fuel pressure is referenced pre-throttle body so it's not going to be referenced to manifold pressure at anything other than full throttle..

[slow_hemi6]

Pretty sure those have siamese intake ports. The upstream injectors are probably less of a nightmare than the mixture robbing issues from trying to port inject it.

[whittlebeast]

You can try something like we did on the Turbo rotary Miata. See the small turnbuckle that bridges the rubber coupler.

http://www.nbs-stl.com/miata/IMAG0286.jpg

Andy

[Steven]

Whittlebeast, looks good but i am going to try the bead first as i have one under the bench, plus i need the compliance to the stationary intercooler.

Slow_hemi6, your right about the siamese ports and i did try port injection and it didn't work, i have a bent push rod to prove it.

Hans5.2, see above regarding injection location, i will try relocating the regulator reference line tonight and report back, i have been thinking i had a 'fundamental problem' for some time i just needed a clue. hope it works...

to all, thanks for the positive feedback.

[R100RT]

Good luck on your "X tau" tuning - that can be rather challenging especially if you're fuel is injected a long way ahead of the inlet valves.
I found such a huge amount of wall wetting when I had my injectors well upstream that I moved them right down to the traditional pre-inlet location and had instant relief and calming effect

[Steven]

T-bolt clamps are the way to go for boost, hose clamps will simply not cut it. Also a "humped" silicone coupler is probably what you seek to handle the movement.

Aside from that, that thing must be a tuning nightmare, injectors are way upstream of the ports, and your fuel pressure is referenced pre-throttle body so it's not going to be referenced to manifold pressure at anything other than full throttle..

Hahns5.2
Just want to double check this, I have bought 'stuff' to move the reference which I'll probably do Saturday but my logic was that the reference was to balance the fuel rail and manifold pressure where the injector 'injected' so that you would get constant flow. Is my logic wrong. I'm going to move the reference anyway because it is a bit if a tuning nightmare.

[slow_hemi6]

Actually as per many TBI units you do not need vacuum reference for the fuel pressure regulator. Your injectors being on the atmospheric side of the throttle blades means the engine is not sucking on the injector so you do not need to reduce supply pressure to correct for that. You do need to reference for boost however so I reckon where you are referencing now is correct. I should mention that there are TBI's with injectors above the throttle plates that are referenced to manifold vacuum but that is more of a fudge along the lines of a rising rate reg. It keeps the idle pulsewidths a bit longer when you are trying to cover an engines whole rev range with 1 or 2 injectors only.

[Hahns5.2]

Well, you can build a good amount of boost pressure above the throttle plate and still be in vacuum in the manifold. If your fuel pressure is rising based on pressure other than in the manifold, I'm not sure that's what you want either. If it was mine I'd put the injectors behind the throttle body.

[slow_hemi6]

Why would you not want it? You actually need the pressure to increase as any positive pressure present is pushing against the injectors outlet. Raising the pressure on the injectors inlet is the only way to achieve linearity of fuel delivery vs PW. Your Map sensor must be always on the manifold side and it will command the required PW.
Aren't blow off valves used to combat the condition of having vacuum on the manifold side while there is positive pressure on the other side?

[Steven]

Dear Collective Wisdom…
I spent half a day last weekend trying to tune (or wake) the beast. I am sure as per my earlier post that I have a fuel condensation issue. The intercooler is working exceedingly well and I will try covering it some. But I wanted to float some other ideas and gauge the feedback. It was clear that the truck would cruse and idle very well, smooth e.t.c. but any acceleration would lead to coughing it just seems like it couldn’t get enough fuel. Detonating and coughing but also rich fuel smell and the AFR gauge not showing anything untoward. So ideas I have been mulling over…
1. Heat the Throttle Body and the base of the inlet manifold to help stop the condensation, I know this is counterproductive when intercooling. It’s an LS truck throttle body and it does have a water heating facility. For the manifold I would weld thick walled aluminum tubes to the bottom and just continue the heater circuit from the Throttle Body?
2. Today I am using regular injectors that inject several times per engine revolution and they are far upstream before the TB mainly because of an issue with the Siamese inlet ports . If I were to go to PWM injectors that if my understanding is correct just ‘fog’ at different rates could I put one in each of the three inlet runners closer to the inlet valve? the three inlet ports have 2 x 360-360 and 1 x 240-480 cylinder timing.

As usual all help gratefully received.

[Steven]

bump...

[Matt Cramer]

What are your IAT readings when this happens? That would help determine if the condensation is likely to be an issue.

A complete data log of the problem might help with other explanations as well.

[Steven]

ive just got a bunch of thermocouples that i am going to put on and log what happens at various points in the system. i'll be back...

[R100RT]

As mentioned in several posts previously, and my mention of Xtau tuning, if your injectors are very far from the inlet ports of the head then you may tend to have a significant "wall wetting" issue. The wetting will stabilize at a certain coating as you cruise - hence okay for that moment of operation.
Any throttle change causes afr to fall lean or rich till equilibrium is achieved again - is hard to tune around.
Hence the value if possible in placing the injectors right above inlet port and spraying directly at the inner face of the inlet valve head.

[Steven Minnesota]

smaller TB and plenum with shorter runners

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long time getting back to this but several things got in the way... First Minnesota Winter and it looks like my old login was blocked (any moderators want to help me out).

Mr. RT i think your exactly right, i have remade the inlet manifold to make it shorter and smaller diameter 2.5" from 4' throttle body and plenum. i have also added water heating for the bottom of the injection plenum and around the top of the 3 into 1 area of the inlet manifold. right now i'm not sure its better still struggling with tuning, running well in the steady state. i may just cut my losses and try and fit a vertical oriented DIY setup or just slap a big old four barrel 'off the shelf' deal on there.

basically just venting at the moment but if someone could take a quick look at these tune and quick log and help me work out why its running at 10:1 all of a sudden i would much appreciate it.

first thing that came to mind was that i had lost spark in two cylinders this would make 14:1 into roughly 10:1 but then i figured it would burn in the exhaust around the turbo.

getting ready to put the 2" single barrel carb back on it.

[billr]

Since this thread is being "resurrected" after a long rest, maybe it would help if you post a re-cap of the present symptoms.

I see the dwell is 4.5 sec, so I gotta ask... are you sure these aren't the type of "almost-smart" coil that auto-fires when dwell get near 4.5?

I think you are backwards about the AFR during a misfire episode. The AFR will go lean then, not rich. Yeah, there will be extra fuel in the exhaust because some didn't burn, but that isn't what the O2 sensor reads; it reads, um... O2, and there is extra of that, too, due to the missed combustion.