Lurksalot Posted May 31, 2007 Share Posted May 31, 2007 I noticed that all the Westies in the race series (1800's) , and of course numerous others ,have the bonnets cut away at the air filter. My bonnet is not cut away . So I suppose my question is , if I were to take a jigsaw to the bonnet would it give me any power gain ....... Kev Quote Link to comment Share on other sites More sharing options...
higgsti Posted May 31, 2007 Share Posted May 31, 2007 your filter would be getting cooler dense air so yes Quote Link to comment Share on other sites More sharing options...
slippy Posted May 31, 2007 Share Posted May 31, 2007 Let it breathe man, let it breathe Quote Link to comment Share on other sites More sharing options...
Lurksalot Posted May 31, 2007 Author Share Posted May 31, 2007 So with cooler air (and the weight saving) these busa engined things won't be able to catch me ............... Has the difference ever been tested or measured by anyone ? Quote Link to comment Share on other sites More sharing options...
slippy Posted May 31, 2007 Share Posted May 31, 2007 So with cooler air (and the weight saving) these busa engined things won't be able to catch me ............... Guaranteed or your money back Quote Link to comment Share on other sites More sharing options...
Lurksalot Posted May 31, 2007 Author Share Posted May 31, 2007 Excellent , on my return from holiday, I shall find a selection of cutting tools, and lay waste to the side of my bonnet , releasing vital space for the vast quantity of air that will chill the the intakes , and provide the dense oxygen rich mixture that will release another brazillion horsepowers from my 1800 zetec ............bring it on Quote Link to comment Share on other sites More sharing options...
higgsti Posted May 31, 2007 Share Posted May 31, 2007 you might need a bigger filter and possibly rejetting Quote Link to comment Share on other sites More sharing options...
MAT1800 Posted June 1, 2007 Share Posted June 1, 2007 Longer trumpets might help too... But I'm not convinced there is a massive power boost to be had. Yet I hadn't thought about the weight saving from the fibre glass you'll loose... No offence intended mate but looking at your avatar a diet and a hair cut... perhaps even a delousing would probably make more difference. Quote Link to comment Share on other sites More sharing options...
Jenko Posted June 1, 2007 Share Posted June 1, 2007 Also, I think we are assuming you currently have a sausage filter pressed up on the inside of the bonnet......If you have K&N filters that fit under, I would suspect cutting a hole will look naff and not do anything to performance........... Quote Link to comment Share on other sites More sharing options...
skymike Posted June 1, 2007 Share Posted June 1, 2007 could you not just take a quick run around the block with the engine cover off to see if there is a difference? I was going to do that this weekend..... I have twin 45's with a p/c filter only a few inches off the side.... I am worried about cutting a hole and making it look crap..... Quote Link to comment Share on other sites More sharing options...
Westy1700 Posted June 1, 2007 Share Posted June 1, 2007 you may, as i have done need to reinforce or support the bonnet to stop it mis forming once you have extracted a huge amount of its strength !! Quote Link to comment Share on other sites More sharing options...
Lurksalot Posted June 1, 2007 Author Share Posted June 1, 2007 Ok so if I understand correctly ,to enable my proposed bonnet modifications to produce the best results, I need to...... a)Cut a hole b) get a bigger filter c) rejet or Re map fuel cycle ...rolling road ? d) fit longer trumpets e)Take a diet , f) get a hair cut , g) get de loused ......and maybe wormed (just to be safe) h) Drive it naked round the block and finally... i) Rebuild the bonnet to add the strength back to it ....... thus cancelling all the weight saving potential hmmmmmmmmm maybe not then I'll go to B&Q and get my money back for the jigsaw Quote Link to comment Share on other sites More sharing options...
Big R Posted June 1, 2007 Share Posted June 1, 2007 no one has mentioned the psychological power increase associated with the intake roar .... Quote Link to comment Share on other sites More sharing options...
Mid life crisis Posted June 1, 2007 Share Posted June 1, 2007 I noticed that all the Westies in the race series (1800's) , and of course numerous others ,have the bonnets cut away at the air filter. My bonnet is not cut away . So I suppose my question is , if I were to take a jigsaw to the bonnet would it give me any power gain ....... Kev You could of course follow the route taken on my car. 36 x 1" holes in 4 rows over the area of the air filters, no loss in bonnet strenth, plenty of cold air plus the weight loss. Quote Link to comment Share on other sites More sharing options...
Glen H Posted June 1, 2007 Share Posted June 1, 2007 you won't see any actual gain on the rolling road as you car would already have been tuned with no bonnet on !!! - its more a case of you will be losing some of the power from the rolling road session due to underbonnet / air intake temperatures. Cutting a hole AND extrending the filters will allow cooler air in which will be more condense / more volume this will then need more fuel to match hence better power. However this said, I THINK longer trumpets may cause a slight loss in BHP but a gain in torque. Overall in my opinion it is worth doing BUT do expect more noise / higher DB readings when tested so if your already close to trackday limits then you may need to address your silencing Quote Link to comment Share on other sites More sharing options...
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