Datsun Spirit ITB's

[jonbill]

Heat shields are for radiant energy, not hot air.

I believe a lot of the heat gain in carbs and itb's is through radiation not convection. I believe Ive got that right. So blocking the line of sight with an appropriate medium greatly reduces heat gain.

I appreciate that, but why bother keeping the TBs cool? Surely they don't transfer a significant amount of heat to the air going in, and they're insulated from the injectors and anyway the injectors and the fuel rail hold very little fuel compared to carbs, so...?
Maybe the answer is that its easy so why not. I'll be installing ITBs over the winter and it's a question I hadn't considered.

[Zed Head]

18 hours ago, northernz said:

Hey Grannyknot, I talked to Eiji at Spirit Datsun about a filter setup, he said "where am I driving, the Sahara?"! Doesn't use them  at all on his car. 

He builds engines.  He probably just rebuilds his every 20,000 miles.  And never drives through construction zones or if the wind is blowing.

[Zed Head]

2 hours ago, jonbill said:

I appreciate that, but why bother keeping the TBs cool? 

Keeping the injectors cool is probably worth doing.  That is the source of the heat soak/hot start problem for many EFI systems, apparently.

If the shields block air flow then they also block hot air rising from the exhaust system.  So, dual function, radiant and convective.

[jonbill]

Keeping the injectors cool is probably worth doing.  That is the source of the heat soak/hot start problem for many EFI systems, apparently.
If the shields block air flow then they also block hot air rising from the exhaust system.  So, dual function, radiant and convective.

Good to know, thanks.

[240260280]

1 hour ago, Zed Head said:

He builds engines.  He probably just rebuilds his every 20,000 miles.  And never drives through construction zones or if the wind is blowing.

I recently rebuilt carbs with no filters. What a pile of dirt and silt inside. The engine is also blowing oil through the top of valve cover so open air engines is not a good thing nor cool based on first hand observations.

I notice a lot of road grit is thrown up by the vehicles in front as they pass over it.  It is very noticeable when traveling behind a truck with a Jersey Barrier on the side. Grit collects at the barrier and you sand blast your car as you drive through the wake of the truck in front.

[siteunseen]

I rembered some honey cone comb looking filters from a few days ago. They looked really good! Finally found them under my nose.

Edited September 6, 2019 by siteunseen

[Patcon]

MikeW also runs a fine mesh filter on his carbs

[240260280]

If you have Weber's, there is an open air inlet to the fuel bowl on the front face that some filters do not cover.

[northernz]

Those honeycomb filters look like the perfect compromise, I really like the look of them.The heat shield works very well for radiant energy off the headers, just using the back of my hand I can feel the difference in temp above and below the shield.

Quote

I'm doing the same.  Super cool setup!

Your set up looks great!

[grannyknot]

You could also go with something like these, great while you are on the road and you can pull them off for car shows.

 

 

[duffymahoney]

If you want. I would sell you my honeycomb filters at a loss. I don’t like the look of them for some reason. The fit is tight. But they work. 

[northernz]

Thanks for the offer, I'll let you know via pm!