Throttle Bodies Over Carbs - What Are Peoples Views?

[Bonzai 2]

i would estimate ive done about 10k miles on bodies now, including 2 ring trips, without so much of a hiccup. Best decision i ever made on my 205 Just be prepared for massive financial outlay, id say £1500 minimum for jenveys, emerald and mapping

[bales 1]

Not true, carbs don't do anything, same as throttle bodies. The engine sucks through the carbs/bodies, airflow result is similar to a charger blowing through.

 

I don't want to tell you how to suck eggs but "standard" carbs have venturi's. Without being geeky this is bernoulli's, where the pressure differential bewteen the inlet which is in vacuum and the float chamber pulls the fuel out.

 

As you said carbs and throttle bodies do suck through and hence their is a vacuum, as soon as you add any positive pressure through a turbo or supercharger you lose the pressure differential and the venturi doesn't work to the same degree.

 

As I mentioned it can be done as it is on a R5 and other older cars but you need to run a higher fuel pressure to overcome the boost and also the carbs needs to be modified.

 

You can also mount the turbo after the carb so it sucks through it.

[shalmaneser 26]

You can also mount the turbo after the carb so it sucks through it.

 

And ruin any pretence of fuel economy at the same time.

 

Many car cos did the carb+turbo thing, including Maserati as well as Renault, and almost all of them were notoriously unreliable!

 

Not looking to take the piss, the stuff you're writing about Bernoulli's principal is entirely correct but a carb plus turbo set-up has basically no redeeming features compared to turbo + TB(s), and doesn't really need to be thought about today.

 

Properly set up TBs vs. properly set up carbs. though? especially if you include ignition mapping there can't be much in it.

 

For me also carbs have somehow always been 'cooler', maybe just because I prefer the 'analogue' way of doing things with screws and shims as opposed to the 'digital' way. Car tuning should be done with a screwdriver not a laptop! IMHO obviously.

[jackherer 543]

webers + turbo + mi16 + 205

[taylorspug 7]

webers + turbo + mi16 + 205

 

I was just going to suggest that aswell. Lovely looking piece of kit. The bloke who used to own it is on here, he PM'ed me a month or so back as he bought an MI id done some work on in the past.

[bales 1]

Not looking to take the piss, the stuff you're writing about Bernoulli's principal is entirely correct but a carb plus turbo set-up has basically no redeeming features compared to turbo + TB(s), and doesn't really need to be thought about today.

 

I know, I said that earlier on the thread, I was just replying to the statement that somebody had said that forced induction works fine through standard carbs which it doesnt.

[base-1 17]

Actually what you've said is wrong. A carb does indeed work on Bernoulli's Principle but not how you say.

 

Vacuum from the open inlet valves does not directly draw fuel in as you've said. The vacuum draws air through the venturi, and it's the flow (and speed of flow) that determines how much fuel is drawn into the airflow.

[brumster 135 1 Cars]

Many car cos did the carb+turbo thing, including Maserati as well as Renault,

 

Aww don't leave out the poor old MG Metro Turbo

 

and almost all of them were notoriously unreliable!

 

'nuff said!

[bales 1]

Actually what you've said is wrong. A carb does indeed work on Bernoulli's Principle but not how you say.

 

Vacuum from the open inlet valves does not directly draw fuel in as you've said. The vacuum draws air through the venturi, and it's the flow (and speed of flow) that determines how much fuel is drawn into the airflow.

 

I think you are being slightly pedantic because I disagreed with what you said. I'm not going to give an in-depth description of bernoulli's principle in a thread that is only lightly related to it am I??

 

I was trying to get across the point that in a normal carb a positive pressure won't work as effectively.

 

I am fully aware of Bernoulli's, I am an engineer and I work in the chemicals industry I was just describing it very briefly, I am sorry if I offended you by my reply, but what you said was wrong thats all.

 

Jeez

[base-1 17]

Yeah I probably am, but I think you are aswell which is why I left it until you mentioned it again - I did deliberately say it was similar rather than "this is exactly what happens" as I also wasn't going to go into an in-depth description.

 

I didn't mean to cause any offence and I'm not offended

[bales 1]

No worries then

[pip470 61]

Just thought this sketch was relevant, so often we can get caught up in im right no im right arguments. Sorry for off topic post.

[VisaGTi16v 1]

Brilliant !

[monty69 6]

Think the turbo lotus esprit used blow through delortos, not sure whether normal ones can be changed like these or how easy they are to get hold of. I was thinking of doing a low boost sc with suck through webers but im thinking the car would be faster with cams as i struggle to grip with 140lbft as it is.

[Sam 4]

That image is from xkcd ... http://xkcd.com/349/

 

Anyway, not sure if its been mentioned but the vscartmax mini supercharger kits use a suck through weber on the inlet side of the charger...