Impoving Air Supply?

Road-race engines and ancillaries - general discussion
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beardybloke
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Impoving Air Supply?

Post by beardybloke » Wed Oct 29, 2014 7:43 pm

My name is Andrew Webb , I have recently joined the forum . I have a 1975 Tvr 1600M which has a Fiat 1600 twincam engine and 5 speed gearbox , this was fitted mid eighties from 131 supermirafiori . I have only owned the car for 2 years and have joined the forum as I need a lot of advice/help to get things running better .
I really like the way the engine pulls and the car is quite light and drives well so it is a nice fun car in this configuration. I have the 32ADF carb which came with the engine and have almost got it to work ok , I wish to improve the air supply to the carb and then maybe consider re-jetting and latter moving to a bigger carb .
Tvr.002.JPG
Tvr.002.JPG (34.92 KiB) Viewed 1500 times
Tvr.003.JPG
Tvr.003.JPG (35.13 KiB) Viewed 1500 times
The 2 attachments show my existing air filter and a cold air duct from the front grill .
I have discussed this previously with GC and have decided that I would like to fit a plenum/snorkel to direct air into the carb and then have an inline filter elsewhere , this would have the benefit of being a sealed system. .Space is limited under the bonnet so everything has to be a bit of a compromise . I would like to know what I should do with the two pipes which appear in picture 2 , the larger one appears to be an oil breather pipe ? and the smaller one comes from the left of the carb ?. Should I fit an oil catchpot to the larger pipe or an oil breather , not sure what the smaller one do if anything ?. Or should I try to repipe into the snorkel ?.
I would appreciate any advice as how to proceed .
GC_100

Guy Croft
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Re: Impoving Air Supply?

Post by Guy Croft » Thu Oct 30, 2014 1:31 pm

Use a catchtank for the oil breather.

Have a look at Phil Gilling's red Fiat Spider in Readers' Cars, you will see it in the underhood region.

I have GC 2 liter capacity (race grade) spec ones made for the TC,

G
Guy Croft, owner

beardybloke
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Re: Impoving Air Supply?

Post by beardybloke » Thu Oct 30, 2014 8:03 pm

Thanks for that G . I have had a look at Phils car , it looks like a lot of time and effort have gone into this build and the result is excellent . I notice that he has used the K+N Apollo filter inconjunction with the plenum air intake as you suggested in our previous discussion , this also looks very good and a neat installation .
If I go ahead with this can I just blank off the small pipe from the left hand side of the carb ?.
I can also see that Phil has used the 32/36 DGV as you recommended previously , at the moment I planned to keep the 32ADF but will probably look to change this in the future . One of the concerns I had with the DGV was that I believe there is no return fuel line whereas the ADF has a return line . I realise that the DGV would be a better carb but would a 34ADF also give a big increase in performance ?. This is for the future as my development will be over several years .
Once I have installed improved air input will I have to rejett and possible set up on a rolling road ? . The one I have asked locally said that they would not carry the jets for the ADF , I assume another reason for changing to the DGV !. Any suggestions on how to approach resetting carb ie increase main jets and also air correctors .
Any helpful advice would be appreciated many thanks Andrew.
GC_100

PumaPhil
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Re: Impoving Air Supply?

Post by PumaPhil » Fri Nov 14, 2014 9:56 pm

Hello Andrew, thanks for the comment about my installation, but tbh once I had installed Guy's engine I had to raise my game in an attempt to make the ancillaries look up to his standard!!

All I wanted to add was that I simply sealed off the return fuel lines under the car near the fuel tank and had an electric solid-state fuel pump installed in the boot. Also, as Guy may have advised, advantages of the 32/36 DGV is that they are relatively cheap, reliable, can be used for engines designed to produce up to around 180 bhp and spares are easy to come by. Finally, I can't recommend the plenum from Webcon enough, it wasn't particularly expensive, it was very easy to fit, it was nice and shallow, but most off all helped cure to issue of warm air causing pinking.

I hope this is of some help to you, regards, Phil Gilling
GC-05
'If you think experts are expensive, you should try amateurs!'

A redline run my GC's engine: https://www.youtube.com/watch?v=80nEhsJbH2w

beardybloke
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Re: Impoving Air Supply?

Post by beardybloke » Sun Nov 16, 2014 1:19 pm

Hello Phil , thanks for getting in touch . I have bought a plenum from webcon and am going to make a base plate adaptor to fit onto the ADF for now . I am probably being a bit stubborn in persisting with the ADF but having spent quite a bit of time on it I plan to give it a last chance before replacing it .
I haven`t used the facet solid state pump as they suggested it should go in the boot next to the tank and I have very little access to the tank and no boot!. I went for an interrupter type as this could go anywhere , as I said everything is a bit of a compromise in my car .
Once again congratulations on a great installation , I have a long way to go ! , Andrew.
GC_100

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