Heatsoaking Fuel Rail - Fix?

RYU

RYU

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We often times ignore fuel temps and it's effects on a tune. I noticed on the CTSC fuel rails they get really damn hot. After some close inspection, I don't think it's radiant heat causing this but instead it's heat coming up thru the heads and the locating bolts that hold the fuel rails in place.

I'm hoping someone has found a solution.

Long shot.. I know.
 
goldNSX said:
Do you have the OEM engine cover in place?
Click to expand...
No, Type R style engine cover

turbolence46 said:
I suppose you could make one that is finned? Like the finned tubes they use for air compressors

http://3.imimg.com/data3/HS/UY/MY-2348677/finned-tubes-500x500.jpg
Click to expand...
Interesting idea. There's still a lot of radiant heat there with little fresh air flow :(

I guess if we're throwing ideas out there.. a water cooled channel thru the rail would be interesting. Seriously, though.. that rail gets TOO hot to the touch. It's the metal to metal contact of the mounting bolts that's transfering the heat I believe.

I'm wondering if the OEM gets as hot. I thought I recall phenolic gaskets separating it. I'll have to look it up...
 
I've never noticed, but then again I've never looked. You might be right though, a small ceramic spacer or something would eliminate the kinetic transfer.
 
I could build something I suppose, I've been busy with the AEM screen, but I'll let you know.
 
The heat in the engine bay is ridiculous. I have mentioned there is not much air flow. I was at the Tail of the dragon which is a 11 mile road with 318 turns. I ended up melting one of the wires on my O2 extension harness from heat. My water/meth was not effective since the road is nothing but turns and couldn't use it. My intake temps were at 200 degrees. I just don't want to put a snorkel on my rear window but it seems like the only way to get cool air in the engine bay
 
We're working on a clever invention (my idea, of course, what else :)) but I won't reveal it at this time.
 
Blacknot said:
The heat in the engine bay is ridiculous. I have mentioned there is not much air flow. I was at the Tail of the dragon which is a 11 mile road with 318 turns. I ended up melting one of the wires on my O2 extension harness from heat. My water/meth was not effective since the road is nothing but turns and couldn't use it. My intake temps were at 200 degrees. I just don't want to put a snorkel on my rear window but it seems like the only way to get cool air in the engine bay
Click to expand...
I'm trying my darndest to install the engine bay fan from my 91 (newer cars got rid of this). It turns on when the high side of the radiator fan comes on. Kaz talks about it here. Visual inspection tells me it will fit however that backwards Prelude alternator makes it damn tight. The fan will probably need to be trimmed somehow. With that said though... air flow won't do all that much to cool the motor but it will certainly help.

I feel bad for some of these guys running these diffusers. You can probably fry an egg on the top side of that thing!
 
I heard through the grapevine that one well prepped open road race prepped car that was having real heat soak that ended up taking the lexan/glass engine cover off and solved the problem ...... perhaps a scoop is the answer for you RYU!
 
Hrant said:
I heard through the grapevine that one well prepped open road race prepped car that was having real heat soak that ended up taking the lexan/glass engine cover off and solved the problem ...... perhaps a scoop is the answer for you RYU!
Click to expand...
I would rather take off the CTSC than put on one of those contraptions! :)

I'm probably overthinking all this Hrant. You're able to run long 20+ min sessions on hot Norcal tracks right?
 
The racer had no choice but to remove the cover, but you and I do have a choice.

After installing the shrouded dual SPAL fans, with the ducting that I have for R-Hood, "most" of my overheating (not the same as heat soak) issues have been resolved - especially if you also opt to shift at no higher than 7300 +/- RPM. But I no longer track at ambient temps of 90+F. The car may handle it but I just feel miserable and I am not investing in a cool suit though they really make a difference.

YMMV
 
As far as the main topic of this thread, the fuel system on the NSX engines are a return style system. the fuel pressure is always going to be high and returned to the tank, so it will heat up over time. Further, the effort to try to cool the fuel rails/fuel lines isn't going to sustain any huge advantages. The engine will be more susceptible to changes in coolant/intake temps

There are many track cars running stock rear glass without problems, having a scoop does help though. If you're having high engine and intake temps, Id look at ways to addressing those (better radiator / intercooler solutions)
 
RYU said:
I noticed on the CTSC fuel rails they get really damn hot.
Click to expand...
I didn't observe this on a extended drive. Even on a hot day they remained quite cool. They were the coolest part of the unit. I think that's because of the fuel circulating within the lines.

But I can not speak for a track day.
 
I wonder of someone could make a downforcelike intake snorkel for the passenger side of the car.
 
RYU said:
We often times ignore fuel temps and it's effects on a tune. I noticed on the CTSC fuel rails they get really damn hot. After some close inspection, I don't think it's radiant heat causing this but instead it's heat coming up thru the heads and the locating bolts that hold the fuel rails in place.

I'm hoping someone has found a solution.

Long shot.. I know.
Click to expand...

What's the surface temperature of the rails? If it's over 120F that is too hot.

One of my concerns while piecing together the custom fuel setup was bypassing the OEM low-load arrangement. Enough to look for engine RPM-based controllers strong enough to handle the current from my fuel pump.

But in the end, I just bought two senders to do data-logging on while I tune the engine: a fuel pressure sender and a fuel temperature sender. If I have a problem with temps, I'll heat wrap the rails and put in the variable speed controller. If I have a problem with fuel pressure fluctuations with ID1000's and low-load tunability, I'll put in Marrin fuel rail dampeners. Well, someday at least!

Measure the rail temps under a variety of conditions (about a 1/4 tank of fuel and various engine load combos) and report back! I take it you don't have the Comptech CF fuel rail heat trappers installed do you?

Dave
 
I think you are going overboard on a problem that imo doesn't exist. A lot if not most of the heat would come from the pump itself anyway and not the cylinder head. I agree with Mase, if you don't already have an effective intercooler for the CTSC time would be better spend on the further development of that.

Edit: I know you are using the supra fuel pump RYU, and that ones uses a considerable amount more amperage vs a walbro or other similar fuel pumps, which may generate a lot more heat, not that it is likely a problem though.
 
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A "Hot to the touch" fuel rail is not something I could easily overlook. I've always had the Comptech CF cover plates on there before so I never bothered to check but since I've had them off during the last few dyno runs I decided to feel them - they're HOT. I have a infrared thermometer i'll use to check temps. If it's not accurate i'll buy some thermo strips. Again, they're hot... I can't keep my fingers on it for more than a few secs. I wouldn't care so much if they were just warm.

I wasn't aware those CF cover plates acted like heat shields? I thought they were purely aesthetic. I'm also using the RDX injectors so I cannot be sure if more heat is transfered thru them from the IM or not.

RE the Supra pump, one would think a bigger pump that's under driven would produce less heat than an over driven small pump. I don't think that logic makes sense. No pun intended lol

It would be nice to know if i'm the anomaly here or if other CTSC folks are noticing this. Again, I never bothered to check before.
 
RYU said:
A "Hot to the touch" fuel rail is not something I could easily overlook. I've always had the Comptech CF cover plates on there before so I never bothered to check but since I've had them off during the last few dyno runs I decided to feel them - they're HOT. I have a infrared thermometer i'll use to check temps. If it's not accurate i'll buy some thermo strips. Again, they're hot... I can't keep my fingers on it for more than a few secs. I wouldn't care so much if they were just warm.

I wasn't aware those CF cover plates acted like heat shields? I thought they were purely aesthetic. I'm also using the RDX injectors so I cannot be sure if more heat is transfered thru them from the IM or not.

RE the Supra pump, one would think a bigger pump that's under driven would produce less heat than an over driven small pump. I don't think that logic makes sense. No pun intended lol

It would be nice to know if i'm the anomaly here or if other CTSC folks are noticing this. Again, I never bothered to check before.
Click to expand...

Regan,

Did you notice this with the old Walbro pump before it crapped out? If so, that pump may have been drawing a lot of current due to it failing, or maybe the current increase was due to suction flow cavitation (or both as they could have been related).

Fuel rail heat soak is a real concern with some applications. Moreso with returnless setups, but return styles can also have issues due to many reasons. I've had to wrap fuel rails in the past with insulation to reduce vapor lock due to heat soak from the engine.

I'm curious what your temps come back as. Since I'm doing my own tuning, I definitely want to monitor fuel temperature even it is to convince myself that it's not impacting my tune. My O2 feedback takes care of that for most of my driving, but the WOT is what I'm concerned about.

Oh, I guess I wasn't clear about the Comptech CF rail coverss. They are pretty, but if your rails are too hot, I would remove them.
 
I decided to drive the car to work today. 1hr of stop and go traffic certainly caused it to heat up quite a bit in the engine bay. My IAT sensor was already heatsoaking itself at 67C/152F off boost with light engine loading. It was 87F outside.

Keep in mind boiling point of gasoline is between 100-400F depending on air pressure.

Seems pretty effin' HOT. Unfortunately, I wasn't kidding when I said, I can't touch it for more than a couple of seconds.

20130626_183620_zps61ddd5f1.jpg


I also don't think it's the fuel pump boiling. The fuel filter had an external temp of 98F. If it was the fuel i'd assume that would be pretty darn hot too. I do appreciate the brainstorming though. Thanks! Any more ideas?

Here's a photo of the RDX before/after. Do you guys think the heat is coming up thru the injectors? I suspect it's coming up thru the fuel rail mounting bolts.
942625_10151494396816588_1568907640_n.jpg
 
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