29 replies to this topic

[stardude]

hi

i am slowing starting to build up a 7-port motor, and i dont know what carb to get. i will be using carbs for a while untill the engine is paid off, then i will upgrade to a set of jenveys

i know in david vizards book, he had found that the dellortos provide finer fuel atomisation, which is better with the 7-port rather than the droplets from the webers.

David Vizzard to say in Auto Performance magazine, “Dell’Ortos produce truly excellent results...On engines where atomisation is a premium requirement, Dell’Ortos are superior to everything”

MED who are supplying the head, use and only use webers and fuel injection on their 7 port builds, so they must be happy with how the webers perform on them?


i was weighing up the pro and cons of each and came to this:

weber pro:

its a weber!
more widely available second hand
looks better and is more recognisable.

weber con:

more expensive
less adjustment available
less MPG than dell
not as efficient through the bottom and middle rev range on the 7-port

dellorto pro:

cheaper
finer adjustment
finer fuel atomisation, beneficial for the 7-port
better MPG
better through the revs

dellorto con:

not as available
more complicated than the weber in terms of tuning it


considering all of the benefits of the dell's, i havnt seen a single 7-port fitted with them

has anyone got a pair on theirs?


i dont know what to use.


if you were doing a 7-port, which carbs would you use?



a confused adam

Edited by stardude, 30 June 2010 - 12:58 PM.

[Wil_h]

To be honest, considering the cost of a set of carbs, I'd go straight for injection.

Buy this book http://www.amazon.co...-...9215&sr=1-3

There are cheaper options than Jenvys.

[stardude]

To be honest, considering the cost of a set of carbs, I'd go straight for injection.

Buy this book http://www.amazon.co...-...9215&sr=1-3

There are cheaper options than Jenvys.

i had beeen looking at twin 40's in the region of £150-200

will get that book and have a read.

i had had a look at MBE roller throttle bodies, but they ar a tad expensive too.

what bodies would you recommend using other than jenveys?

how much would a throttle body setup cost?

Edited by stardude, 30 June 2010 - 01:34 PM.

[Wil_h]

If you used a Megasquirt I reckon you could a a full injection system for less than £500 with a bit of inginuity. Dave Walker (who wrote the book above) dosen't like the use of throttle bodies off bikes, but it can be very cheap. The reason he dosen't like them is that ensuring all the butterflies are set the same is fiddly on bike ones iirc (not sure why it's hard).

My plan is to use a single throttle body and a plenum (but I will have a turbo). This makes the throttle body cheap as any scrapyard will have loads, but you will need to fabricate a plenum with inlets, injector mountings etc. this may be time consuming, but not expensive.

Of course you'll need a return fuel line, and fit trigger wheels etc, but in reality, you should be fitting mapped ignition anyway to make the best of you spangly 7-port, so you're half way there anyway.

In my head a pair of webbers were more than £300, seems cheap.

[stardude]

it is going to be mapped ignition, was going to use megajolt with carbs, but then i considered injection lol

for some reason bike bodies dont appeal to me. would rather use carbs or spend a bit more and get some nice throttle bodies.

[mini13]

do you have the head yet?

as your looking at webers/ delorto's i assume your looking at either the minisport or webcon head, but i have to say the specialist components head looks good for the price, especially the bundle they do for about 2500quid with all the injection.

[Kerrin]

If you are going to go for injection in the long term, it is worth considering how much you will spend on the carb setup as a temporary measure.

Fuel pump, secondhand webbers, throttle linkage, fuel pressure regulator, ignition only ecu etc

Then consider how much will be re usable with injection. I suspect almost none. The carbs may need a rebuild, and how much will it be worth secondhand?

You will need to re wire a new ecu re plumb the fuel flow and add a return and re jig minor items.

I am not sure but will carbs need a hole in the front of the bonnet for clearance, but the injection fits under the round nose.

We priced up injection verses carbs for a zetec in Dads mk1 Escort. If you buy new there is hardly anything in it. The new mk1 we are building is going to have mj and carbs but only due to the fact they came with the car, and even then I am tempted by injection.

There will be two lots of rolling road tuning to add to the bills as well.

In answer to your original post I think they stopped making Dellortos in the mid nineties so if you want new webber is the only option which is why med probably only deal with webbers.

Edited by Kerrin, 30 June 2010 - 05:13 PM.

[stardude]

now im even more uncertain of what to do.

for some reason i dont want to go with the SC head. i want to run the webcon head with carbs to start untill i am happy and can afford to go to fuel injection

my original plan, was to get the webcon head from MED, and run webers on it for quite a while untill the engine is paid for and the car is to a standard i want. then i can save or splash out in one go and get some jenveys or similar dcoe style throttle body. i wouldnt be running injection for quite a while.

if i use webers and megajolt, i could then sell the webers for roughly the price i paid for them and help towards to the bodies as well as sell the other associated bits. The megajolt can then also be put on my other car or sold, to help pay for megasquirt.

the engine will have the edis system setup on it so all that would be needed would be to bolt on the bodies, wire up the squirt, change the fuel system.

lol i started this thread about wether to use webers or dell's

i think i will use webers due to a few different reasons.

[mini13]

LOL,

well, i'd say go all or nothing (sort of)

dellorto's will be tricky to find (much trickier than webers anyway) so go webbers,

If your thinking about going for injection later on i'd say either get the injection ecu now or run a dizzy, the reason I say that is there will be extra sensors for the injection ecu over the megajolt (water temp, throttle position, lamda, air temp)

how about a turbo?

[mini-man-dan]

Have a look through summs116's rebuild. I've been out in the car, and even before it's been setup on the rollers it's unbelievably fast...

LINK
Dan

[mini13]

I think i'd belive how fast it is lol,

about as quick as mine would be at 20,000ft above sea level PMSL

[stardude]

LOL,

well, i'd say go all or nothing (sort of)

dellorto's will be tricky to find (much trickier than webers anyway) so go webbers,

If your thinking about going for injection later on i'd say either get the injection ecu now or run a dizzy, the reason I say that is there will be extra sensors for the injection ecu over the megajolt (water temp, throttle position, lamda, air temp)

how about a turbo?

so if i used megasquirt just to drive the ignition untill throttle bodies were installed, would i have to use a TPS? am i right in thinking that megasquirt doesnt use a map sensor?

how is your turbo? what sort of power do you get from it? im a bit too scared to venture into the world of the snail!

Have a look through summs116's rebuild. I've been out in the car, and even before it's been setup on the rollers it's unbelievably fast...

LINK
Dan

i have been paying close attention to his rebuild, and have been in touch with lots of PM's. its amazing!




god! megasquirt is complicated!

[mini-geek]

why not get the secialist components set up? one stop shop if you ask me.

[mini13]

megasquirt uses both map and TPS sensors, although you can just use a TPS sensor if your going NA, and probably just use the MAP sensor on its own instead of the TPS (not actually looked at that...)

Your right megasquirt is complicated, mainly because of all the options that it can provide, and hence all the information on the website. If you go the megasquirt route (or think about it) i would recomend you look at one bit at a time and decide what you need, start with the crank trigger, then the coil setup, then look at the injection bits, drop me a PM if you need any pointers.


the "snail" is not that scary, its quite good because you end up with a very drivable car (until you wind the boost up!)

i've (still!) not managed to get mine on the rollers yet due to bending a valve last year at MITP due to not enough clearance on the valve guides (the minisport heads seem prone to this on the centre two guides) and having a cam belt go at the start of this year... so i dont have a power fig, but it seems as an evo 6 or 350z on about 9psi, and on 18 it will absolutely annihilate an elise, 1st will see 45, 2nd 65, 3rd about 100, 4th I don't look down,

from those speeds this will give an indication, it was on a private road so its ok to say that at the end of the vid i change into 4th about at 90, thats on just 7 psi,

[stardude]

well, looking at the SC setup, once tax is added, it goes up to £3k

whereas the head i am looking at will cost £1.7k, carbs £175 ish, megasquirt ???

i reckon, when i want to swap to throttle bodies (if i ever do) i can sell the carbs for roughly the same and manage to put together a pair of jenveys or similar with fuel rail and bits for £1k ish.

by doing that i reckon it will cost near enough the same (ish)

i think that makes sence but i am very tired and its very late plus i have have had a few drinks