Nozzle placement and IAT sensor spacing

[BDC]

Hey guys, I've got a question about whether or not there needs to be an (x) distance between alcohol injection nozzles and an IAT (intake air temperature) sensor. I'm curious as to whether or not there needs to be a measured amount of distance and time for the alcohol to flash and freeze the charge for an IAT sensor to accurately see it. Anybody have any data on this? On my old plumbing setup, I had a cast aluminum throttle body inlet adaptor piece that bolted in front of the throttle body that housed both the injection nozzles and the IAT sensor. When datalogging while boosting, I would see the IAT's shoot up but then rapidly drop the instant I went to decel. On the current setup, I've got the injection nozzles plumbed into the charge pipe about 3.5-4" before the IAT sensor that's sitting just in front of the throttle body. Check the picture below for a closer look. Am I over-thinking this or would it be prudent for the purposes of air temp/fuel corrections and accurate datalogging to move the nozzles further upstream?

Btw, glad to see some of you Turbobuick piston-head alcohol guys again on here. Haven't been on the forum in awhile. My red Mazda rotary has been parked for awhile while other stuff was goin' on. I just recently removed the ridiculously inefficient stock top-mounted intercooler and converted it to hot-air. I'm trying an experiment to see how efficacious alcohol in the charge acts as a "chemical intercooler" as it were on this setup with the heavy alcohol to gasoline ratio I use.

B

 

[Razor]

I thinks your thinking too much. Understand that resistor thermocouples are a tad slow to respond. So dont put to much faith in them for speed.

Thanks for the eye candy.. looking good

 

[BDC]

I thinks your thinking too much. Understand that resistor thermocouples are a tad slow to respond. So dont put to much faith in them for speed.

Thanks for the eye candy.. looking good

Thanks Julio. Alright, I won't goof with it then. If it ain't broke, I s'pose don't fix it.

The nozzles are now on the top and bottom of the 90* pipe that's connected up to the blue 3" to 2.5" reducer on the throttle inlet. Was a pain to get 'em in but it works. I've noticed in my prelim testing that I'm going to have to move the TurnOn point back counter-clockwise a bit. I'm getting turn-on point around 7-8lbs of boost with the 30psi head pressure light kicking on about 11psi. With this new hot-air setup, the IAT's are rocketting up prior to any decent volume of alcohol coming on so I'll have to work on that a bit.

 

[Razor]

Have you looked into pre-turbo injection?

 

[BDC]

Wasn't aware if you'd recommend it for your system or not so I've never looked into it.

B

 

[Razor]

Wasn't aware if you'd recommend it for your system or not so I've never looked into it.

B

You also had an IC at the time you did this originally :tongue:

You can branch out another nozzle like an M1 and you wont have any puddling.. you have the perfect setup.. just a thought :wink:

 

[BDC]

You also had an IC at the time you did this originally :tongue:

You can branch out another nozzle like an M1 and you wont have any puddling.. you have the perfect setup.. just a thought :wink:

Any negative effects from running alcohol pre-turbo like that? I wouldn't mind trying adding an M1 up in front of the turbo if there's no degredation of the compressor wheel/housing from it.

B

 

[BDC]

An update on this even though Julio and I have already talked. Even though I'm a hot-air guy, I s'pose this applies to everyone doing alcohol.

I was previously having a bit of knock and very high IAT's so I moved the nozzles from just aft of the throttle body down closer to the turbo and staggered them out. The move can be seen in the pictures attached. I went out and beat on the car yesterday (Jan 21) for about an hr. Below is posted from yesterday afternoon.

Ambient temps out here today are in the mid 70's if not closer to 80*F. I think the weather guy on the radio said it'd be 78*F out. That's about what it feels like. Cruising IAT's on the highway were around 115-125*F. The same ~45*F difference between ambient and cruising IAT's seems to still remain a constant.

Still running the same map w/ the same TurnOn point of boost (bout 3-4psi; 8:45 o'clockish) with the fuel map setup as an 80/20 ratio (80% gasoline and 20% methyl alcohol) by 15psi and holding steady above that. AFR's today were in the low-mid 10's:1. Spent about 45 minutes or so of seat time with Jarred (eJayce996) helping me w/ the laptop in the passenger seat. Having him there allowed me an opportunity to watch more things while I progressively ran the car harder. I was able to get a rough scale of numbers to compare actual EGT temperatures to the Spare A/D +5VDC numbers. This will enable me to log the actual temps instead of merely relying upon a gauge.

Top EGT I saw pre-turbo was about 1650-1660*F. I'm still not sure what the acceptable heat range is for this setup but my gut says it's a bit warm up high. Because of it, I may go ahead and add 5% more alcohol to the mix and fire the spark one degree ahead. It might be that I don't have enough advance as it is at higher boost levels.

The engine didn't knock one time and I beat the crap out of it.

In finality of this post, I think I can say that at even a 20% replacement of fuel with alcohol means not only a higher fuel octane rating in the charge to enable way high boost but more importantly a charge cooler that is far superior to air-to-air intercooling alone. The only thing left that I'd like to get answered to feel comfortable about saying that with conviction is to run it longer and harder to see where the air temps stabilize. So far, the pattern is the IAT's remain at a flat temperature commensurate with boost and do not fluctuate according to RPM or time.

I'll post up one or two datalogs in this followup post. Julio, let me know what you think. With this amount of alcohol and possibly displacing 5% more fuel to go to a 75/25 ratio, I'm curious what the AFR target range ought to be if I normally do low 11's:1 on 100% gasoline. Even though it's a matter of debate, doesn't the lambda shift between the two fuel types?

Also, here's what I have for EGT to 5V conversion so far using the O2Simulator EGT -> +5VDC adaptor:
1370 3.78
1455 4.06
1470 4.10
1500 4.20
1510 4.22
1580 4.47
1600 4.50
1635 4.57
1650 4.71

B

 

[BDC]

Here's two datalogs comparing IAT's between a 1bar-16psi run and a run at 22psi with AFR's hanging low-mid 10's:1. This EFI system is an older Haltech E6K. The Spare A/D column on the right shows the logged EGT voltages via the O2Simulator adaptor straight off the Type K probe. Boost/vacuum are on the 2nd to left column with IAT to the right of it. The IAT sensor is located in the 3" aluminum adaptor bolted to the front of the throttle body at the tail end of the hot-air pipe.

BDCHA16

BDCHA20

 

[Razor]

Brian, sorry havent had a chance to shout back at you. Been in the middle of a move.

I think its pretty wild to see those temperatures slammed way down especially without an IC. And the proof is in the datalog. Guess having that long plumbing from turbo to TB has allowed this to happen. Pretty neat.. My hats off to you. Really.

I'll try and call you tommorrow. How this applies to a Buick dont know.. but it poses some neat questions and definetely some needed testing staggering nozzles way apart.

Keep up the good work.. glad to see you're having fun..

 

[BDC]

Glad I could help. Hope it helps some others on here who do Hot-Air. Perhaps a cross-link over to the Hot-Air section is worthwhile?

B

 

[Razor]

Done.. put a post in the hot air section

 

[Jerryl]

To get that close to ambient is not only very cool , but amazing!

I have not been able to get to ambient (Not that I was trying :tongue: ), but, I think on a HA-TR, it may be a bit more of a challenge. Let me share my thoughts.

I “think” that the IAT placement and the length of the evaporative path makes a big difference.
In the current stock PAC HA configuration, there is X inches distance from injection point to the MAT (after the turbo) and not much time (distance) for the methanol to fully evaporate, depending on “how much” you spray.
Replace 5%, no issues. Replace 30%, you need more “time”, and thus longer length.

The MAT measurement for a TR HA is typically somewhere in the intake manifold.
The heat that is radiated into the bottom side of the TR HA intake also increases intake temp charge, but, also assists in evaporating greater amounts of methanol.
Of course, there is always a point of diminishing returns. What that is, I have no clue.
Need someone real smart to calculate this to be used as a “target goal”.

Paging J. Estill and Dr. C. James

Cool stuff!

 

[TType84]

using a multi nozzle multi line setup as intended by buick from the very beginning would be interesting to see

 

[Jerryl]

Brian,
Can you rehost the pics, PLEASE?

 

[Boost231]

brian,
can you rehost the pics, please?

+1

 

[Razor]

Here you go guys, Brian was kind enough to send them to me a few months back.

Cheers..

This was the email sent,
"Hey Julio, we talked about 2-3mo ago about this so here I am, sending you my specs, in a timely fashion. I'm attaching a few pictures you can put up if you'd like. I've also had a thought of pushing the success of the hot-air experiment, due to your system, in your next magazine article if you're approached anytime soon. It'd be a huge win for you.

1988 Mazda Rx7 Turbo II
Half-Bridgeport 13BT 8.5:1 Rotary Engine
Master Power T70 0.96 A/R P-Trim running 24-25psi of boost
Alkycontrol Progressive Alcohol Injection system using twin M10 nozzles, staggered and fitted upstream
No-intercooler "Hot-Air" system using alcohol injection as 'chemical intercooling'
Calculated 200*F temperature drop in turbo discharge temps (from 296*F to 99-102*F at 24psi of boost on a 71* day)

Hope that does it.

B"

 

[bison]

Here you go guys, Brian was kind enough to send them to me a few months back.

Cheers..

This was the email sent,
"Hey Julio, we talked about 2-3mo ago about this so here I am, sending you my specs, in a timely fashion. I'm attaching a few pictures you can put up if you'd like. I've also had a thought of pushing the success of the hot-air experiment, due to your system, in your next magazine article if you're approached anytime soon. It'd be a huge win for you.

1988 Mazda Rx7 Turbo II
Half-Bridgeport 13BT 8.5:1 Rotary Engine
Master Power T70 0.96 A/R P-Trim running 24-25psi of boost
Alkycontrol Progressive Alcohol Injection system using twin M10 nozzles, staggered and fitted upstream
No-intercooler "Hot-Air" system using alcohol injection as 'chemical intercooling'
Calculated 200*F temperature drop in turbo discharge temps (from 296*F to 99-102*F at 24psi of boost on a 71* day)

Hope that does it.

B"

Chemical intercooling is no joke. Sometimes my IAT is below ambient for a couple seconds as it spools up with the dual nozzle. After about 10 sec WOT it only crept up 14 degrees above ambient last night to 76 degrees at 140mph. 6100rpm in 3rd. This is with an intercooler though. Still moving a lot of air the engine is over 750hp. Im sure having the methanol as close to its boiling point before injecting has an even quicker effect on dropping IAT's. This is a good thing for guys who want to be competitive in THS. They can make up for the smaller turbo and compressor cover with added meth to drop the temps down. THS will be a mid/low 9 sec class if anyone gets really into it.

 

[BDC]

Good stuff!

My question is why did the setup suddenly work when the nozzles were moved away from the throttle body and placed up stream? There something having to do with time to flash the alcohol or something? That's my only guess. When I had them in the hotair pipe just aft of the TB, at just 1bar of boost the IAT's reached over 150* and the motor rattle canned loudly. With them moved up stream, the temps were a few degrees below ambient at the same boost and it ran terrific. What gives?

B

Chemical intercooling is no joke. Sometimes my IAT is below ambient for a couple seconds as it spools up with the dual nozzle. After about 10 sec WOT it only crept up 14 degrees above ambient last night to 76 degrees at 140mph. 6100rpm in 3rd. This is with an intercooler though. Still moving a lot of air the engine is over 750hp. Im sure having the methanol as close to its boiling point before injecting has an even quicker effect on dropping IAT's. This is a good thing for guys who want to be competitive in THS. They can make up for the smaller turbo and compressor cover with added meth to drop the temps down. THS will be a mid/low 9 sec class if anyone gets really into it.

 

[GNVYUS 1]

Good info, good to see someone on here is showing what I've been saying for a while now, put the nozzles as far from the TB as possible. There have been other tests years ago that proved the further away, the better the temps due to the amount of TIME needed for the Meth to cool the charge.

Now that you can see the temps, you can determine if you need bigger nozzles or more pressure. :biggrin:
70 degree cylinder temp (after injector sprays gas/ethanol/methanol) is the cold threshold so 100 degrees at the TB still has some room left for more Meth. :wink:

The Hot Air pipe is too close to the cylinder.