John Bonnett
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| posted on 24/4/08 at 07:36 PM |
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Measures to lower under bonnet temperatures
I would like to thank everybody who responded with suggestions to combat high under bonnet temperatures and hot air being drawn into the carbs when
stuck in traffic. Also for the suggestion of using a maplins temperature monitor. I have done my best to implement these suggestions and I collect the
temp. monitor tomorrow.
I have fitted bonnet side vents and on the intake side, the vent has a scoop to encourage air to enter the bonnet. I have also made a duct fitting
tightly to the air filter and terminating as close to the bonnet side vent as possible. Also a forward facing scoop mounted on top of the bonnet
should push air out diagonally exiting just forward of the scuttle on the drivers side. This I hope will discourage air from migrating from the
exhaust to the inlet side. I haven't tested the mods yet but I am hopeful.
I don't know how to post multiple pictures but everything is in my archive.
Once again, thank you for your help and advice.
John.jpg)
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John Bonnett
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| posted on 24/4/08 at 07:37 PM |
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Cold Air Duct.jpg)
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ed_crouch
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| posted on 24/4/08 at 09:20 PM |
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Sounds silly, but make sure you've got both the fuelling and ignition set nicely, as these both affect EGT quite significantly.
Then its down to getting plenty of fresh air through the engine bay. Turbotape if you like, but it does (apparently) tend to encourage corrosion on a
non-stainless header, and its heavy. I dont believe all that bullshit about improved exhaust scavenging - well, it might give you 0.5 BHP under ideal
conditions...
I think you've already done one of the best mods - prevent hot air from getting into the carbs. My dad used to own an E28 BMW M535 with an E34
3.6 M5 engine in it (by christ did it go!), and on the rollers, we "found" 30+BHP by putting a bit of corrugated cardboard between the rad
fan and the foam air filter: went from 290 to 320 flywheel.
The only thing you might do is double-skin the headshield to prevent the inside surface heating up...
HTH.
Ed.
P.S. Oops, youve got Jenveys(?) rather than webers... Still, same applies re the fuelling. I found my TVR was definitely cooler under the bonnet after
a RR tune up - was running too lean and hence EGTs were up.
[Edited on 24/4/08 by ed_crouch]
I-iii-iii-iii-ts ME!
Hurrah.
www.wings-and-wheels.net
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