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Thread: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

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    Bodger

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    2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    Currently my 2.1 Silvertop is running with 45 webers and Megajolt.

    Have read that changing back to Original manifold with different injectors could perform better than webers.

    My webers lack a mid range progression hole which creates problems in getting the right mixtures despite being setup on a dyno going through the progression through the rev range.

    I've read with the silvertop, Japanese injectors are needed with increased flow (Subaru/Skyline). The blacktop has a greater choice of off the shelf injectors, but would a blacktop manifold fit a silvertop.

    So what would be my options as its fitted in a Kitcar.

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    for whatever reason the zetecs do prefer the 5 progression hole webers. stuttering on progression is common if not used.
    any standard injector of correct size will do, no difference between silvertop / blacktop injector preference to my knowledge.
    however, they all have same manifold pattern.
    running non standard injection will require a new programmable ecu.

    hope thats of some help.

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    Thanks,

    As I am restricted as I think the Silvertop manifold intake is rear facing, can the Blacktop manifold fit easy enough to get its forward facing intake.

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    if your otherwise happy with webers why not just get the correct ones? your going to loose top end power going back to a standard manifold for sure, plus your need someone way to run injection.

    if you were to go injection, then as your need an ecu, you might as well, swap your webers for 45's and get best of both worlds

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    Spanner Monkey

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    yeah I would agree, swap to proper 5 progression holed webers mate. makes sense...

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    Just send them to Weber and get them drilled, or do it yourself, no need to change carbs

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    Thanks,

    Have visited various forums on this topic and there seem to be pro's and con's regarding the 5 progression holes.

    Some say even with 5 holes the carbs still don't run as they should with a Zetec even after hours spent on a dyno.
    Most say the car has to be present to precisely drill the holes in the correct position, then its trial and error plugging and redrilling till the correct position is found also with the hole dia. As no 2 Zetec's perform in the same way with air flows on each carb.

    As for TB's most suggest using a ST170 lower manifold on bike TB's or a GBS single pendulum manifold with a ST170 throttle body.
    Most seem to use GSXR 600-1000 TB's with the ST manifold and use injectors in the ST manifold.
    Some use a adaptor tube between TB's (round) and manifold (oval), others use a heat gun and reshape the ST manifold from Oval to Round eliminating the adaptor tube.
    And some say the latter is Plug and Play, where various maps could be stored and used accordingly where only the Ign map could be stored with Carbs also strip and change jets etc.

    From this I am leaning to bike TB's and ST 170 manifold where it would easier to set-up having maps for Track days and maps for Road use.

    thanks again.

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    So what is so different on a Zetec engine that it will not run properly on "normal" Webers?
    Or is it due the camshafts for Zetec engines?
    Has anyone tried back to back testing?

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    I don’t really know.
    The cams are far as I know are Std, just its bored to 2.1 by previous owner with paperwork to show.

    I’ve had it on 3 different dyno’s and each has struggled with the carbs and they say it will run imperfect till the holes are sorted.

    As read elsewhere about Zetecs on 45 dcoe’s all have said the carbs must have the 5 holes or even some say that don’t always sort it either.

    Various forums say its a Zetec thing with airflow rates. ??

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    2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    I will answer later on laptop but most your being advised is tosh.


    Sent from my iPhone using Tapatalk

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    Quote Originally Posted by escortkid View Post
    Thanks,

    Have visited various forums on this topic and there seem to be pro's and con's regarding the 5 progression holes.

    Some say even with 5 holes the carbs still don't run as they should with a Zetec even after hours spent on a dyno.
    Most say the car has to be present to precisely drill the holes in the correct position, then its trial and error plugging and redrilling till the correct position is found also with the hole dia. As no 2 Zetec's perform in the same way with air flows on each carb.
    theres no reason zetecs would not react in a similar manner to my knowledge, its massed produced to close tolerances after all ? and the carbs dont have room to drill and plug, an expert will know where to drill when tuning it

    As for TB's most suggest using a ST170 lower manifold on bike TB's or a GBS single pendulum manifold with a ST170 throttle body.
    a single body will tune easily but cost power , the lower st manifold is a cheap bodge and will never flow correctly due to miss matched shapes -not required really as t/b's are cheaper these days . gsxr bodies are good as the early ones split , i cant imagine the re shaping working well tbh.
    Most seem to use GSXR 600-1000 TB's with the ST manifold and use injectors in the ST manifold.
    Some use a adaptor tube between TB's (round) and manifold (oval), others use a heat gun and reshape the ST manifold from Oval to Round eliminating the adaptor tube.
    And some say the latter is Plug and Play, where various maps could be stored and used accordingly where only the Ign map could be stored with Carbs also strip and change jets etc.
    none are plug n play without spending a lot. and since the suggestion is that maps can be stored and used in different engines ( which i agree with to a degree) then that makes nonsense of the suggestion earlier that all the engines are different ?

    From this I am leaning to bike TB's and ST 170 manifold where it would easier to set-up having maps for Track days and maps for Road use.
    thats a home brew lash up to be honest and not the way to go for " plug n play " reliability , and if its mapped correctly you only need one map ? unless using different fuel or intake etc.....

    thanks again.
    i have answered in the quote above. my opinion only.

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    Quote Originally Posted by Miniliteman View Post
    So what is so different on a Zetec engine that it will not run properly on "normal" Webers?
    Or is it due the camshafts for Zetec engines?
    Has anyone tried back to back testing?
    to my knowledge they suffer a flat spot on the progression stage even with 4 hole. the 5 hole webers were introduced i think specifically for zetecs ?
    maybe onyd can shed more light if he comes across this thread.

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    I’m using DHLA dellortos 48’s on my 240 horse ST170, no issues at all

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    Some say even with 5 holes the carbs still don't run as they should with a Zetec even after hours spent on a dyno.
    Most say the car has to be present to precisely drill the holes in the correct position, then its trial and error plugging and redrilling till the correct position is found also with the hole dia. As no 2 Zetec's perform in the same way with air flows on each carb.
    theres no reason zetecs would not react in a similar manner to my knowledge, its massed produced to close tolerances after all ? and the carbs dont have room to drill and plug, an expert will know where to drill when tuning it
    What some say, if the drilled hole is in the wrong position. They use metal filler to plug and redrill

    As for TB's most suggest using a ST170 lower manifold on bike TB's or a GBS single pendulum manifold with a ST170 throttle body.
    a single body will tune easily but cost power , the lower st manifold is a cheap bodge and will never flow correctly due to miss matched shapes -not required really as t/b's are cheaper these days . gsxr bodies are good as the early ones split , i cant imagine the re shaping working well tbh.

    Most seem to use GSXR 600-1000 TB's with the ST manifold and use injectors in the ST manifold.
    Some use a adaptor tube between TB's (round) and manifold (oval), others use a heat gun and reshape the ST manifold from Oval to Round eliminating the adaptor tube.
    And some say the latter is Plug and Play, where various maps could be stored and used accordingly where only the Ign map could be stored with Carbs also strip and change jets etc.
    none are plug n play without spending a lot. and since the suggestion is that maps can be stored and used in different engines ( which i agree with to a degree) then that makes nonsense of the suggestion earlier that all the engines are different ?
    To reshape, they fit a wide band bolt clamp tightening to reshape using the heat gun
    As for plug and play, meaning plug in a laptop and change various settings. The storing of maps, meaning for myself experimenting till right with road and track use.



    thanks

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    plug and play generally means you connect it up and it works without user knowledge or input.
    all ecu can be tuned at home if the skill is there and map can be tinkered with but the engine does not know where you are circuit, garage , high street, - unless your doing pikes peak where air mass changes massively on the climb then if map is correct then its correct.
    Last edited by alladdin; 13-05-2018 at 22:56.

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    INFO:-

    The main problem with the carbs which none of the 3 dyno's could solve using the 3 existing progressions, is progressing from above tick over without it popping etc from the carbs and missfire till approx 2000 rpm when it settles from there up.

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    duplicated
    Last edited by escortkid; 13-05-2018 at 23:11.

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    At tickover it runs ok. But between approx 1600/1800 it pops and missfires back through the carbs till above on a light throttle.

    Any clues

    thanks
    Last edited by escortkid; 14-05-2018 at 20:58.

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    What idle jet do you use?

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    Idle jets are:- 55 F8

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    Re: 2.1 Silvertop on 45 Webers v OEM mainfold + injectors

    Quote Originally Posted by escortkid View Post
    which none of the 3 dyno's could solve using the 3 existing progressions
    45DCOE's (the modern ones) have 3 progression holes, 45DCOE152G has 4 progression holes, 45DCOE for Zetec special has 5.

    Change to 55F6, that will probably cure the misfire.

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