Carbs, carbs and carbs

[fastcar1cars]

Been lookin at carbs for my c20xe nova! The engine is totally standard but i have a aftermarket exhaust manifold to go on! Now should i go with twin 40's, twin 45's or bike carbs?
What torque would i get with each setup?
What bhp would i get with each setup?
And which would give best mpg? Its a daily!
Cheers

[MK999]

Carbs on a daily won't be the best for MPG but if set up properly should see high 30's driven carefully. Dellorto's are the best option imo and for a standard XE you want no bigger than 40's up to well over 200bhp even.

[blue_peg_16v]

I ran 48 lol they were awsome on my xe

[MK999]

They will supply air and work, but you get a better intake velocity out of 40's and it's not like 40mm is a restriction until you're running silly bhp.

[fastcar1cars]

Yeah was goin to do bike bodies on standard management but thought carbs may be better!
So 40's would be better than 45's?
What sort of torque figure should i get?

[blue_peg_16v]

Tbf my engine was alot less worked on than phils (2.1 bottom end hi comp pistons larry cams head work etc) mine had 48s standard bottom end and a set of Qed cams with Sbd manifolds but phils has the bigger Sbd mans mine also has full leather interior and stereo install were as Phils is stripped bare and. Every time we raced on the quarter in those specs he literally had his bonnet infront of mine nothing more ill admit I never beat him but it was always very tight he runs 45 me 48s I'd never run 40s as there ok on a mild engine but as with everything you always get bored and want more is cams etc and 45 give you the scope to improve in the future 40 restict that
I also used it as an everydayer in that spec and it was fine on a run I actualy got more than standard but if you kicked it's head in it drank for England 80 miles to tank once lOl

[blue_peg_16v]

They will supply air and work, but you get a better intake velocity out of 40's and it's not like 40mm is a restriction until you're running silly bhp.

40 max venture is 32 mm so not 40 mm

[Mazz]

40 or 45's? ca'nt you just change the jets to suit?

[Bean,]

We built a redtop at work for a grass car, was std apart from kent cams and 48 webers. That pushed out 200bhp at the wheels.
The last one we built had high comp intruders, cams, stainless steel valves, solid lifters and 45 webers that pushed 250bhp at the wheels.
My personal preference would be webers everytime.

[Angus Closier]

Or you could just go for 45's and choke them if needed untill you run a bigger spec....same with 48's....

[novaxe235]

Bean Did it really? and where is it you work, lol!

[Bean,]

Work for a motorsport company. And thats the power figure's our rollers kicked out. I was there when they were tuned
The 200bhp was in a Class 6 corsa. Did have a quaife diff and straight cut box
The 250bhp was in a starlet with lsd and straight cut box.
Our rollers are pretty spot on give or take 5%. Both engines were freshly built and fully end to end balanced as well.

[MK999]

45's are also about 4 times the cost though, harder to get hold of and aren't gonna cause any issues until the spec gets silly enough to warrant fuel injection over carbs imo. 40mm trumpets/32mm venturi is the same carb still... it's still equivalent to a 64mm TB if you're running twin carbs, which is sufficient to see 230-250BHP without thinking about changing it (Vaux V6 is a 60mm TB iirc)

Mazz, both 40's and 45's will fuel correctly/the same, but the air velocity through 40's will be higher (think squeezing the end of a hosepipe to make it smaller, velocity increases and it fires out the end rather than trickling) It's this speed/momentum that packs air into a cylinder. It's not purely a case of less restriction is better, it's a careful balance of velocity and restriction, depending on the air requirements of the engine.

Webers are very good carbs, but Dellorto's follow the same design principles and have jets in steps of 1, not 5. You can fine tune the fuelling on Dellorto's a lot better which ultimately yields more power/MPG and a better running engine in general. What spec cams went in it? They'd have to be pretty mental duration with small lift to work on standard pistons and produce 200bhp.

[turbojolt]

A cam and carbs made 200hp???

[Bean,]

The cams were Kent AST1612's. Std pistons but now you mention it we did have the valve pockets enlarged slightly

[novaxe235]

Work for a motorsport company. And thats the power figure's our rollers kicked out. I was there when they were tuned
The 200bhp was in a Class 6 corsa. Did have a quaife diff and straight cut box
The 250bhp was in a starlet with lsd and straight cut box.
Our rollers are pretty spot on give or take 5%. Both engines were freshly built and fully end to end balanced as well.I cant understand why race engine builders bother with any more than a rebuild and a set of cams then, the likes of Frank Anderson and SBD would love to know your company's secrets.

[fastcar1cars]

Engine is 100% staying standard internally i.e head, cams and bittom end!
So would i get a power diffrence between 40's and 45's?

[Angus Closier]

45's are also about 4 times the cost though, harder to get hold of

When did 45's get hard to find? I sold a set today for £227.....Not exactly expensive either....jetted for a xe?

[Bean,]

There's no secrets mate. We take our time and build them with great care. Theres a lot to be said for attention to detail. Had a 1.4 8 valve on the rollers this week. My boss built it 5 years ago and the blokes only just had it set up. lol Was a trick build and made a strong 140bhp.

[turbojolt]

I swear sbd get around 185 HP from a fully set up throttle bodied xe how can carbs be better the them ?

[Angus Closier]

I swear sbd get around 185 HP from a fully set up throttle bodied xe how can carbs be better the them ?


I have seen 250BHP on an xe with twin 45's....


Depends what has been done....whats fully set up?

[MK999]

When did 45's get hard to find? I sold a set today for £227.....Not exactly expensive either....jetted for a xe?

Compared to 40's when I had a look on ebay a while ago they were doing £5-600 a pair, and there was 1/2 pairs compared to 10 sets of 40's?

[turbojolt]

Ment to put in fully set up managment/ecu, and I'm on about this whole just having cams and carbs making 200 HP mate seems a bit odd

[Angus Closier]

I cant understand why race engine builders bother with any more than a rebuild and a set of cams then, the likes of Frank Anderson and SBD would love to know your company's secrets.


Agreed Last one of franks engines I saw was running at 248BHP and came in around 12k

[novaxe235]

There's no secrets mate. We take our time and build them with great care. Theres a lot to be said for attention to detail. Had a 1.4 8 valve on the rollers this week. My boss built it 5 years ago and the blokes only just had it set up. lol Was a trick build and made a strong 140bhp.Obviously there is 200 bhp at the wheels is around 230 at the fly maybe more, Ive been there and done it with a good engine builder that charges £11,000 for an 2.0xe fully built and prepared for a national hotrod, making between 235-250bhp on a dyno, your company can do that with a set of Kent cam's and a rebuild.

[Angus Closier]

Compared to 40's when I had a look on ebay a while ago they were doing £5-600 a pair, and there was 1/2 pairs compared to 10 sets of 40's?

Clearly been a while since you got any? I would never pay more than 300 for a pair tbh...As I would allways have them rebuilt if I got them from ebay etc.


As said, I sold a set of twin (pair) 45's (dellorto) with trumpets and chokes and set of extra jets and a new gasket set for £227


Didnt expect to get any more than that for them. And wouldnt pay anymore for them myself.

Got a set of 40's a year ago for £50

[novaxe235]

Agreed Last one of franks engines I saw was running at 248BHP and came in around 12kAs ive said above mine came in at about £8000 and that was a few years ago now.

[Angus Closier]

As ive said above mine came in at about £8000 and that was a few years ago now.

Worth every penny no doubt from anderson race engines....

[Bean,]

OK just spoke to my boss.
The 200bhp corsa was flywheel power. sorry my misstake
The 250bhp starlet was at the wheels and had a fair bit spent on it. Was on solid lifters some headwork, large bore exhaust and other little touches

[novaxe235]

Worth every penny no doubt from anderson race engines....
Most certainly is.

[MK999]

Clearly been a while since you got any? I would never pay more than 300 for a pair tbh...As I would allways have them rebuilt if I got them from ebay etc.


As said, I sold a set of twin (pair) 45's (dellorto) with trumpets and chokes and set of extra jets and a new gasket set for £227


Didnt expect to get any more than that for them. And wouldnt pay anymore for them myself.

Got a set of 40's a year ago for £50

Fair enough, I had a quick look a month ago or so, basically because we get rebuild kits in at work cheaply, and I wanted to know exactly how they work better, so I was gonna recondition a set for educational purposes, then sell them on. That's the prices I saw them at for a couple of weeks running.

[fastcar1cars]

Engine is 100% staying standard internally i.e head, cams and bittom end!
So would i get a power diffrence between 40's and 45's?

???

[turbojolt]

8k on a engine I can understand why but don't think I could ever spend that myself on one lol is the engine in a race car mate ?

[MK999]

You'll obviously get a power difference as it's a difference size intake. Powerband will be the main thing, 45 will peak more in the higher range (outside of the flow rates of a standard 2 litre imo) and for your engine I will say it will be more drivable and have more power throughout it's range on 40's. This is based on a few years studying the fluid dynamics behind it and also direct engine tuning modules at uni, my personal experience subject reading in various books/forums etc, looking at various working setups and specs with that knowledge in mind and a few months working at an engine builders who deal with a lot of carb builds/setups. There's obviously a few different opinions in this thread though and as with most engine setup stuff it's gonna be up to you what you go with depending which you believe/understand/agree with more.

edit: 8k sounds like a cheap engine to me :p Swindons XE back in the 90's retailed for around 30 iirc :)

[fastcar1cars]

Would there be a mpg diffrence between 40's and 45's?
What bhp would 40's produce compared to 45's on my engine?
Also what torque would 40's produce compared to 45's on my engine?
Cheers

[MK999]

How long is a piece of string? No way to say for sure, it depends on wear in the engine, the condition of the carbs, who sets them up, which way the wind is blowing and what temperature it is (and yes those last 2 do actually affect it :p)

You'll get a better MPG with 40's imo, for the reasons I stated before.

[turbojolt]

How long is a piece of string?
Twice half its length

[fastcar1cars]

Cool and more torque with 40's?
More bhp with 45's?

[MK999]

More BHP possible out of 45's if you can get the airflow that they like, you will have more torque and BHP from 40's on your engine imo.

[novaxe235]

8k on a engine I can understand why but don't think I could ever spend that myself on one lol is the engine in a race car mate ?Nope it's in my nova in my pic there <<<<<<< track/road car, which has'nt been out since october last year, no time at the mo to use it, hopefully next year it should see some use.

[Stuart]

imho on a 100% standard engine you will NOT see a power difference between 40's and 45's, and PROPERLY setup they should use the same fuel.

I'm sure I've read that 40's on an XE give you NO extra power but you do get a nice hike in low end torque.... could be BS, but that certainly sounds nice.

[fastcar1cars]

Would proper ignition management like weber alpha givw better mpg than a cav dizzy setup?

[Adam]

That would help all round seeing as you can actually map the ignition rather that bang a dizzy on and hope it gets it somewhere close.

[Stuart]

its still going to be terrible lol

[jonn]

i went with r1 carbs and megajolt ecu for my c20xe

[womble sri]

With the price of fuel these days and the gain you will get from just putting a set of carbs on a standard engine, it would certainly not be worth it on a daily driver! (unless you have money to burn)

[blue_peg_16v]

Why my carbs when driven normally were just as economical as the injection when you brayed it yes it drank more than father jack but driving normally it was fine and I ran it on carbs for 2 years as an everydayer again it's down to set up with carbs poor set up poor fuel economy

[Paul]

We built a redtop at work for a grass car, was std apart from kent cams and 48 webers. That pushed out 200bhp at the wheels.
The last one we built had high comp intruders, cams, stainless steel valves, solid lifters and 45 webers that pushed 250bhp at the wheels.
My personal preference would be webers everytime.

I have piper cams, QED dth TBs, SBD Type C manifold, Saab red injectors, MBE management. (Rebuilt engine, Z-LET oil pump new gaskets/rings/bearings etc.)

A slightly better spec than cams and 45s, but you seem to have made maybe 40bhp more. Can your company map/tune my engine? And what power would you expect to see from that? 250whp or maybe more?

Thanks

[Bean,]

Sorry mate we dont do TB's we only do old school carbs.
AS i corrected the post the 200bhp was fly power not at the wheels
I would expect your setup to give you a nice 190 - 200 bhp

[Stuart]

Why my carbs when driven normally were just as economical as the injection when you brayed it yes it drank more than father jack but driving normally it was fine and I ran it on carbs for 2 years as an everydayer again it's down to set up with carbs poor set up poor fuel economy

Aside from carbs not really being 'that' perfect even when setup by someone I'd approve of (saying that Dans 1.6 made epic fuel economy on a run lol)

[Mazz]

I was tempted by carb's tbh, but after reading some post i'm not so sure now...I quite like the reliability of EFI

[fastcar1cars]

So on a standard xe with larger exhaust manifold and twin 40's set up well what power/torque/mpg would you predict i would get?
The xe is a good one and its on an f16 c/r box!

[Stuart]

oh as its a good one it will do 200bhp and 50mpg

[Angus Closier]

imho on a 100% standard engine you will NOT see a power difference between 40's and 45's, and PROPERLY setup they should use the same fuel.

I'm sure I've read that 40's on an XE give you NO extra power but you do get a nice hike in low end torque.... could be BS, but that certainly sounds nice.

IMO That sounds about right, Being slightly more restrictive could help low end.

I guess power wise on a standard engine it depends on which chokes are in the 40's and 45's as you might see more power from the 45's at the very top of the rev range?

[fastcar1cars]

oh as its a good one it will do 200bhp and 50mpg

Sweet! Lets get some carbs!!!

[Paul]

FAO fastcar & Bean

Sarcasm, Definition, Meaning Of and Examples Of Sarcasm
Sarcasm is the use of language that subverts the user's true meaning or position in order to be scathing or attacking. Specifically, sarcasm is intended to be cutting or wounding to a third party in one's subversive use of language. The roots of the word sarcasm appear to be from the greek sarkasmos which derives from sarkazein and translates as "to bite the lips in rage"1.

Sarcasm can be ironic, especially if expressed without making it clear that the user is being sarcastic. However, within the last 30 years, as sarcasm has become increasingly prevalent in society, it is no longer the case that sarcasm is delivered "dead-pan" and is more often than not delivered with emphasis that ought not be there. It seems that sarcasm is, by some, not regarded as a particularly witty or clever behavioural trait. In Sartor Resartus, Thomas Carlyle wrote of sarcasm:

[Jeff16v]

I've yet to see the outcome of the strip, clean and balance of the twin 45s on Nicks old car. It's being done in a few weeks. What I can say is they aren't as scary as I thought they'd be. Apart from the odd miss since I got it they've worked well, and I do drive this in traffic to work.
If you buy then already setup the expensive/time consuming bit is all done for you. My guess is that the car will be transformed even more once they are all sorted.

[fastcar1cars]

Jeff16v what mpg u gettin from ur setup?

[Jeff16v]

Not sure about town but got to billing and back on about £25-£30 about 160 miles.

[Paul]

Working on jizz @ £1.40 litre about 40mpg that is Jeff

[Stuart]

Even buying them 'setup' for the engine you have you will still need to get them fine tuned on the rollers. Same goes for management with a base map.

[scott.parker]

Bean do you work at TTP in Bromsgrove? IF he does guys, then these are true figures/facts.

[Jeff16v]

Working on jizz @ £1.40 litre about 40mpg that is Jeff
That sounds about right for 60mph all the way there and back Paul

[fastcar1cars]

Bean do you work at TTP in Bromsgrove? IF he does guys, then these are true figures/facts.

TTP the best place to get carbs setup? Bromsgrove is 15 mins from my house!!!

[fastcar1cars]

That sounds about right for 60mph all the way there and back Paul

40mpg!! Thats ace!!

[scott.parker]

Well Beans from Bromsgrove mate, so I'm guessing there ain't to many places lol it's smaller then Stratford!
And yep thats why i said it, as my mate has had his mk1 escort set up there loads of times when it was on carbs, it's now on bodies.

[Bean,]

Yep TTP is my place of work. We do quite a lot of work on Historic racers and autograss cars.
My boss is **** hot when it comes to setting up cars.

[scott.parker]

Bean, Do you know Rich Savage from Redditch with the Blue mk1 Escort I'm on about?

[Bean,]

Not sure mate. Reconise the name but cant put a face to it.

[Stuart]

Well Beans from Bromsgrove mate, so I'm guessing there ain't to many places lol it's smaller then Stratford!
And yep thats why i said it, as my mate has had his mk1 escort set up there loads of times when it was on carbs, it's now on bodies.



That dosent fill me with joy and promise.... unless he kept changing things on the engine to warrant lots of setups ;)
Set them up once and thats it, if they are good at what they do ;)

[fastcar1cars]

Yep TTP is my place of work. We do quite a lot of work on Historic racers and autograss cars.
My boss is **** hot when it comes to setting up cars.

Mate how much is it to set up carbs at ur place?

[scott.parker]

That docent fill me with joy and promise.... unless he kept changing things on the engine to warrant lots of setups ;)
Set them up once and thats it, if they are good at what they do ;)

Trust me he's had lots of set ups on it... he's silly really he's spent over 14k on building/re building the engine, had to do a full re build as Jamie at JAM fooked it on a map he did once it went over to TB's It's been mag featured in oldskool ford a few times, i don't have any pics of it, was at the auto sport international show NEC the other year.

Here goes, just google his name, and it's come up on there as he has it some times displayed in his dad's work place, heartless ford in brum.

http://www.flickr.com/photos/10509226@N05/3309206218/in/photostream/

No engine pics though..

And he's no longer on FB els i would get some of there.

Scott

[Bean,]

Mate how much is it to set up carbs at ur place?

£90 for the first hour £50 for every extra hour after that. Most of the time an hour is all thats needed.

[Stuart]

so no real info as to if his carbs were shagged (bent spindles) and just setup over and over and over again without someone knowing what to do/check for?.... I think you can get the gist of where I'm going with this lol

[scott.parker]

so no real info as to if his carbs were shagged (bent spindles) and just setup over and over and over again without someone knowing what to do/check for?.... I think you can get the gist of where I'm going with this lol

Yes your a pedantic sod! lol

No his engine was fine, he just has had it setup due to improvements, like new head work, new cam, new this that, blah blah blah, till he then went to TB's then got it smashed to **** by Jamie at JAM sport etc.. so re build and had it set at TTP, so they do do TB's, well least they did for him, as I'm sure Richards dad knows the guy who owns the place, and TTP stands for TO THE POINT. EG no ****ing about lol

[fastcar1cars]

Would bike carbs be better fuel and power wise?

[scott.parker]

Would bike carbs be better fuel and power wise?

Dude ask your self something, would T40's for a Nova/Corsa be a good set up to use on a bike??

General answer is.. No, bike carbs are for bike, car carbs are built for cars simple in my opinion, not being funny mate.

Scott

[mk1nova_rich]

A carburettor is a carburettor though...there are different designs. As long as its capable of supplying the engine with sufficient air and fuel in the correct ratio then its a load of bollocks why it cant be used

[Angus Closier]

A carburettor is a carburettor though...there are different designs. As long as its capable of supplying the engine with sufficient air and fuel in the correct ratio then its a load of bollocks why it cant be used

Yes but mores to the point is the velocity in which the air fuel mixture is supplied.

We really don't need to go into this again as its argued till blue in the face, Bike carbs do work (fact) However ask yourself, why would they design something for a bike if it was going to be used on a car? 13000rpm is not common on car engines......more so road going ones. The air flow at those speeds is massively changed from when it was at 8000rpm........

I Don't see why people don't just use dcoe style carbs designed for that job in mind?

You can pick up a decent set of 45's for the same money as bike carb set ups now!!

[scott.parker]

Yes but mores to the point is the velocity in which the air fuel mixture is supplied.

We really don't need to go into this again as its argued till blue in the face, Bike carbs do work (fact) However ask yourself, why would they design something for a bike if it was going to be used on a car? 13000rpm is not common on car engines......more so road going ones. The air flow at those speeds is massively changed from when it was at 8000rpm........

I Don't see why people don't just use dcoe style carbs designed for that job in mind?

You can pick up a decent set of 45's for the same money as bike carb set ups now!!

Thank you!

I don't claim to know loads about carbs, but what you said makes sense to me, and this is what i think to.
Fact is if i was to put carbs onto one of my engines i would buy and use something thats meant to be used on it, you know it works, all the parts are available etc..
I would not want to **** about trying to bodge parts and faff with bits to make something try to work when it's not meant to be used in the first place on the application your trying to.
Basically i think bike carbs would be horrid to fit/use on either my xe or my 1.2.
I cant think of one person who's not had issues and had to faff around for ages when fitting bike carbs, so why bother?

You wouldn't fit motor bike wheels to your ****ing nova would you??

[fastcar1cars]

Ok so twin 40 delorto it is then!!!
What else do i need?
Can i make a manifold myself?

[Angus Closier]

Can i make a manifold myself?

I dont know can you?

[fastcar1cars]

Well i can weld! So is it poss? Or easier to buy one?

[MK999]

Depends if you can TIG weld ally.

Air velocity on a 1000cc bike at 13k will be similar to that of a 2l at 6.5k btw, bike carbs are quite well proven in various setups, although I've never seen a back to back comparison. Don't see why you'd go to all the hassle of making up manifolds etc though when there are manifolds available for carbs already, as well as then finding somewhere that's kitted out to tune bike carbs on a dyno that will handle a car.

[jonn]

i fitted bike carbs to my c20xe because it worked out cheaper for me. for a set of twin 45s it would cost me €350 i still needed to get a fuel pump and a dizzy.
i got the bike carbs+fuel pump for €120 i made my own manifold which only cost me about €20! i got a mappable megajolt ecu setup aswell.

i have to get the nova mapped on a rolling road when its ready... which could be a while lol
i dont know much about twin 40s or 45s but from what i heard they can go out of tune and can have problems with cold start.

[Stuart]

i dont know much about twin 40s or 45s but from what i heard they can go out of tune and can have problems with cold start.

as ever, only if you buy shagged carbs, or have new carbs setup by a spastic.