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Author: Subject: Should I Open-Up Bonnet-Bulge Vents?
scootz

posted on 31/8/11 at 07:15 PM Reply With Quote
Should I Open-Up Bonnet-Bulge Vents?

I've had to fit a 'bulge' to the bonnet to clear the V8 engine. Thankfully I had a GRP one lying about in the garage, so it will do.

I'm just wondering whether or not to open the vents? The engine-bay temps are ridiculously high... would opening the apertures help?

Cheers.









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Mark Allanson

posted on 31/8/11 at 07:18 PM Reply With Quote
Getting air into a seven engine bay isn't the problem, its getting it out!





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scootz

posted on 31/8/11 at 07:30 PM Reply With Quote
That's my concern!





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Jon Ison

posted on 31/8/11 at 07:34 PM Reply With Quote
I would set somthing up to get the hot air from the rad deflected up and out before it reaches the engine bay, I did this on one and threw the fan away, if anything I had problems getting up to optimum temp not keeping temps down
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austin man

posted on 31/8/11 at 07:54 PM Reply With Quote
open the sides up to create a flow of air same as the Dax really helps to get rid of the heat





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scootz

posted on 31/8/11 at 07:57 PM Reply With Quote
Cheers Jon.

The rad-heat is minor. It's the heat from the exhaust manifolds that's causing problems.





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scootz

posted on 31/8/11 at 07:58 PM Reply With Quote
quote:
Originally posted by austin man
open the sides up to create a flow of air same as the Dax really helps to get rid of the heat


Worth a try!





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Jon Ison

posted on 31/8/11 at 08:20 PM Reply With Quote
May be minor but it's heat from the engine your trying to cool then your flooding it back into the engine bay to heat the engine to cool it again if that makes any sense, honestly it will make a huge difference to engine bay temps
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loggyboy

posted on 31/8/11 at 08:25 PM Reply With Quote
quote:
Originally posted by scootz
Cheers Jon.

The rad-heat is minor. It's the heat from the exhaust manifolds that's causing problems.


Are they wrapped?

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scootz

posted on 31/8/11 at 09:03 PM Reply With Quote
They were, but the wraps were flaking to pieces, so I took them off (I never put them there).





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Chippy

posted on 31/8/11 at 10:28 PM Reply With Quote
Hi Scootz, this is a picture of how I overcame the same problem with my V6. Just made up a couple of alloy vents as shown, worked a treat. Excuse missing gaurd, lost on the way to Stoneleigh, :-) HTH Ray

[img] Showing vent
Showing vent
[/img]





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bi22le

posted on 31/8/11 at 10:35 PM Reply With Quote
I have a vent right above my manifold. the amount of heat distorsion bellowing out of it when im standstill is incredible. let the vents do the work when stand still and the rad do the work when moving.

solves all problems.

word of warning. too many vents and lots of speed means a bonnet lost at 100mph on the motorway!!





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franky

posted on 31/8/11 at 10:47 PM Reply With Quote
I use vented wings and have no issues. Not a fan of wrapped exhausts as they cause more problems than they slove.
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NeilP

posted on 31/8/11 at 10:51 PM Reply With Quote
Wot Bizzle sed.

Vents directly above manifolds are of massive help when at standstill (when your cooling load is at it's highest, ran fan or not). Put them on mine and it massively reduced the spikes in temp I was getting when queuing in traffic after a blat...

HTH, N.





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Mr Whippy

posted on 1/9/11 at 07:37 AM Reply With Quote
what a mad bonnet

I think you have way to much air getting in, then expanding with the heat and can't get it back out again, the bonnet side vents should have been at the back not the front

[Edited on 1/9/11 by Mr Whippy]





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scootz

posted on 1/9/11 at 08:10 AM Reply With Quote
Cheers guys!

I'll extend the bonnet vents on the side along the full length and add a vent to the side-panel





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scootz

posted on 1/9/11 at 04:22 PM Reply With Quote
Step 1 complete... now to make some Daxy style side panels!








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Mr Whippy

posted on 2/9/11 at 10:55 AM Reply With Quote
hmm that engine is huge, I mean just nuts





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StuartBJ

posted on 4/9/11 at 01:31 PM Reply With Quote
Hey Scootz,

Its all about big engines in small spaces ...... good work


You definatly need to get air flowing through that engine bay and not the engine bay acting as a wind sock..... try modding a few ideas like these and the vent above....which is a great 7 mod.

1) Can you add any lourves? on the bonnet? one the side panel? That would solve a lot of issues.

2)Heat management.... I would give serious consideration to adding a reflective layer to your body work interior, even if its a simple layer of aluminium tape, if its getting that hot underneath then it may be a few quid well spent..... Ive been in a car when the fibreglass caught and the whole car went up in smoke in 2-3 minutes..... and wrap those exhausts back up for sure, or cam coat them etc.

3) What about your rad? Do you need to swap it for a deeper one? Fans?.... can you uprate them to a hight airflow, I think mine are about 1000cfm each.....and you could always go for an electrical water pump if you were so inclined for total optimisation.

Hope thats given you some food for thought?



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scootz

posted on 9/9/11 at 11:17 AM Reply With Quote
Cheers Stuart.

I've swapped out the old rad for a larger ali one.

Side vents have been made and fit well...








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sprouts-car

posted on 9/9/11 at 11:41 AM Reply With Quote
Wow thats a big vent. Luck the engine is so big, otherwise it'd fall out the side!





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scootz

posted on 9/9/11 at 11:43 AM Reply With Quote
I made it wide enough for the exhaust to exit through it.





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Macbeast

posted on 9/9/11 at 04:35 PM Reply With Quote
By coincidence, I was doing mine today




Now to see if the plastic melts or the paint blisters



[Edited on 9/9/11 by Macbeast]





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