IAT Sensor heat soak - Potential solution?

[AceOfHearts]

So when I first installed my Megasquirt I installed the IAT sensor in a bit of stainless pipe that was where the the AFM used to be. Even after lagging I used to suffer heat soaking of the sensor which caused the engine to run lean for a couple of minutes after stopping the car (say at a petrol station)

I got around this by relocating the sensor to the front of the car, in the rubber hose next to the air filter.

However now that the car is being turbocharged I have to rethink this and don't want to suffer the same issues I had previously. It looks like the MX5 guys mount their sensors in the cold side of the intercooler to avoid these issues, but obviously this is a fair way from the engine still so not ideal.

I have just ordered a silicone t-piece to attach to the plenum and my idea is to mount the sensor in the 'T' part, and silicone obviously being a better insulator than stainless steel I am hoping it won't suffer the heat soak issues as much.

What do you guys think, or how do you get around this issue?

[BoostedChim]

Sounds like it could work. Mine is in some ali pipe with a boss that I welded in and it would do the same as yours when hot. The boss was quite tall so I cut it down as much as I could to get the sensor into more of the air flow and its been much better since. The other solution was one that John Halstead came up with, the sensor is mounted in the plenum base using one of large holes for the one valves and uses some tufnol carp as a reducer and to insulate it.

Not a great pic, but the only one I could find. I'm sure john put a post on here about at some point.
https://tvrengineer.files.wordpress.com/2013/03/wi...

[N7GTX]

Powers fitted mine next to the dump valve.

[Pupp]

Mine is also in the dump valve tee but my DV is right against the plenum... used to be in the nose when NA and got the soak issue there but no apparent problems now, at least not that cause real difficulties...

[AceOfHearts]

Thanks everyone, interesting ideas.

Any pics Pupp? I will have to look at them at home as annoyingly thumbsnap is blocked at work

Edited by AceOfHearts on Thursday 8th September 14:11

[cinquecento]

I solved this problem by increasing the after start enrichment at operating temperatures. Try abt 20% more ASE..with an extended ASE taper (again at operating temps)

[Pupp]

Tapped and loctited into the underneath of the ally DV tee here (heat rises) - old pic but still using the same set-up. Often does take a couple of goes to start when warm and recently run but stable once going

[BoostedChim]

Pupp said:

Tapped and loctited into the underneath of the ally DV tee here (heat rises) - old pic but still using the same set-up. Often does take a couple of goes to start when warm and recently run but stable once going

Nice setup, what are your temps like with the chargecooler? Is your air filter still behind the rad?

[Pupp]

Thanks - Inlet temperatures seem well under control from the CC, typically 3 or 4 degrees above ambient whereas those into it from the turbo obviously rise much more under load/boost (have seen as high as 80 deg)... bottom line is the CC seems very effective indeed at stripping heat and stabilising I/C temps and with road use, I have seen no noticeable soaking (the CC and heat exchanger in the nose are invariably stone cold after a run... have even seen condensation on the CC).

The air filter is still in that location - I had intended to let a flat panel filter into the bodwork jast ahead of the coolant rad but that now has a canted oil cooler there so have left the filter as is until I can come up with another plan. In practice it has not been the issue I thought it might be although I suspect it could do with being bigger.

[Dominic TVRetto]

In my original set-up (standard plenum with standard butterfly, pre my current 71mm butterfly plenum), I got the IAT fitted into the plenum itself - still got it (with IAT in place) if you interested... PM me...

[N7GTX]

Pupp said:

The air filter is still in that location - I had intended to let a flat panel filter into the bodwork jast ahead of the coolant rad but that now has a canted oil cooler there so have left the filter as is until I can come up with another plan. In practice it has not been the issue I thought it might be although I suspect it could do with being bigger.

Gary, mine is right at the front of the car in front of the intercooler laid down so not blocking it.;)

[AceOfHearts]

N7GTX said:

Pupp said:

The air filter is still in that location - I had intended to let a flat panel filter into the bodwork jast ahead of the coolant rad but that now has a canted oil cooler there so have left the filter as is until I can come up with another plan. In practice it has not been the issue I thought it might be although I suspect it could do with being bigger.

Gary, mine is right at the front of the car in front of the intercooler laid down so not blocking it.;)

That's what I wanted to do with mine but due to the size of the turbo the pipework would need to take too many tight turns and be prohibitably restrictive. Atm I have the air filter directly on the turbo so will see how that goes

[Pupp]

It'll be fine... for all that I would *like* to place mine somewhere more ideal in pure heat avoidance terms, the realities of the plumbing will inevitably offset any benefits to some degree... best for me is probably an 'up and over' the radiator into the nose void but I really cannot see it making so much difference as to be a priority currently

[N7GTX]

AceOfHearts said:

N7GTX said:

Pupp said:

The air filter is still in that location - I had intended to let a flat panel filter into the bodwork jast ahead of the coolant rad but that now has a canted oil cooler there so have left the filter as is until I can come up with another plan. In practice it has not been the issue I thought it might be although I suspect it could do with being bigger.

Gary, mine is right at the front of the car in front of the intercooler laid down so not blocking it.;)

That's what I wanted to do with mine but due to the size of the turbo the pipework would need to take too many tight turns and be prohibitably restrictive. Atm I have the air filter directly on the turbo so will see how that goes

Powers got around this problem by using convoluted reinforced pipe like tumble dryer stuff - only stronger of course.
The air filter lies on the floor in front of the radiators just behind the grille. The ducting then runs through the inner wing on the nearside. It then does a U turn and is placed at the bottom of the radiator where it runs parallel to the radiator and fitted on to the turbo. It is a good fit but below the radiator heat.
You can just make the ducting out in the photo if you enlarge it. It can be seen between the chassis cross member (grey) and the rad fan cowling. If you want pics of the whole route let me know and I'll take some and post them up.

[AceOfHearts]

Thanks that's what I tried but no room. Where is the wastegate on that setup, are they running internal?

[N7GTX]

Its at the front and towards the bottom. Very hard to see without being on ramps.

Edited by N7GTX on Monday 12th September 23:22

[Pupp]

All the Power ones I have looked at have used an integral waste-gate turbo - certainly helps keep the installation neat and minimal