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Throttle response

Discussion in '308/328' started by Sigmacars, Apr 3, 2019.

  1. Sigmacars

    Sigmacars Formula Junior
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    Jul 19, 2006
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    Can the experts here tell me how to get faster throttle response on my 328,at +3000rpm it is ok but from 1000-3000 it is not so good even with no load I mean from idling to 3000.i think it must be the weak cams in these cars.
     
  2. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
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    Drive another known good car to be sure nothing is wrong with yours. CIS injection is known for less than great throttle response but you need a baseline. CIS will not tolerate anything but RV like cams. I bored and stroked mine to 3.55L and put 11:1 compression in it. Made a very good difference but it still isn't and never will be a 360. I did a lot of experimentation on a Mercedes 6.9 years ago with help from Ron Iskianderian advising on cams and we found going just a hair beyond stock cam grinds on a CIS engine and you very quickly start going backwards in performance.
     
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  3. miketuason

    miketuason F1 World Champ
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    Will a lightened flywheel help?
     
  4. Ferraridoc

    Ferraridoc F1 Veteran
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    Put Webers on it
     
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  5. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Two Time F1 World Champ
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    I mentioned this before a little while back here; I almost bought an 80 308 that had been modified with some sort of EFI. It was pretty old because I remember them saying they didn't have a laptop that could talk to it anymore and it actually looked like something from Radio Shack (I had know the car and owner here in town for 20 years) - but the low end throttle response was SO much different from my 84 QV. It didn't feel like it had more power, it would just pull INSTANTLY and I loved it.
     
  6. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Two Time F1 World Champ
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    That isn't always the best idea on a street car.
     
  7. Martin308GTB

    Martin308GTB F1 Rookie
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    And I always thought, the 4V-engines are so much better regarding throttle response, than my carb car. I have only driven a 328 once and instantly noticed the poor throttle response compared with my car. But since it was a Swiss car with catalysts, I thought it has something to do with them.
    Is it the same on Euro cars without exhaust gas treatment?

    Best Regards
    Martin
     
  8. Rifledriver

    Rifledriver Two Time F1 World Champ

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    Well now there is a giant step backwards.
     
  9. Rifledriver

    Rifledriver Two Time F1 World Champ

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    Um, before suggesting all nature of poorly thought out solutions to a non existent problem, think maybe he should be looking into seeing if the car is running correctly or is that just a dumb idea?
     
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  10. Rifledriver

    Rifledriver Two Time F1 World Champ

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    You'd put a light weight flywheel on an engine whose strong suit is torque?
     
  11. thorn

    thorn Formula 3
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    Fire, ready, aim. ;)
     
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  12. Martin308GTB

    Martin308GTB F1 Rookie
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    Bulletproof vest on.

    A crisp throttle response is -for me- an existential important attribute of an italian sportscar. Or better said, sportscar in general.
    Where is the giant leap forward, if it goes to the dogs with a mundane Bosch K-Jetronic? Fuel consumption? Not really on a fun car. Environmental legislation? Less maintenance? Maybe, but that doesn't impress me on a hobby car. Perhaps on my daily driver.
    But somehow it's not the K- or KE-Jetronic. This FI behaves completely different -namely great- in a Volkswagen Golf GTI MK1.

    Meanwhile I remembered, that I not only drove a swiss 328 once, but a Germany delivered 3.2 Mondial without catalysts too.
    Was disappointed too about throttle response.
    Even my little '72 Alfa 2000 GTV with its pair of Weber DCOE feels more sharp regarding throttle response.

    Best from Germany
    Martin
     
  13. smg2

    smg2 F1 Veteran
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    CIS will always have a delayed throttle response, it's worse on the Ferrari's because the distance from the throttle plate to the air baffle is very long. On the Mercedes and VW variant the throttle is right below the baffle plate. CIS is a mass air & hydrolic fuel system, thus the air mass signal has to transition from the throttle to the baffle plate then back again... Hence delayed response.
    Modern EFI and carbs do not have this.
     
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  14. Rifledriver

    Rifledriver Two Time F1 World Champ

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    Carburetors and K Jetronic...I know hard to believe but they are not the only 2 fuel delivery systems know to man.

    Carburetors belong in museums. They had no purpose to mankind since the mid 50's.
     
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  15. johnk...

    johnk... F1 Veteran
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    Jun 11, 2004
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    Throttle response below 3000 RPM in an injected 3x8 is an oxymoron. :)
     
  16. johnk...

    johnk... F1 Veteran
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  17. Ferraridoc

    Ferraridoc F1 Veteran
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    Well, he said throttle response. I didn't have to account for any other parameter! :p
     
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  18. Martin308GTB

    Martin308GTB F1 Rookie
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    I know, but thought we are talking about Ferrari 308 and 328 here. And maybe contemporary comparisons.
    And when I compare a Volkswagen Golf GTI with K-Jetronic with a Ferrari 3x8 with a K-Jetronic, I get the impression, that VW did a great job.

    Best from Germany
    Martin
     
  19. Lowell

    Lowell Formula Junior
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  20. Lowell

    Lowell Formula Junior
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    As far as I can tell, that photo of a pile of carburetors has noting to do with the discussion in this thread as I cannot find a Weber in it.
     
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  21. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    275
    Morning,
    I have a 328 US Specs, have never driven a carbureted 308, so can't compare, with this said, I have noticed that proper air/fuel mixture adjustment on the K-jet is crucial, on engine performance and acceleration.
    Adjustment is done at idle, yet affects the whole power band. I've you don't know how to adjust it, it will drive you nuts... a "very small" adjustment makes a "big" difference.
    I adjust it with an Innovate analog gage, which comes with a wide band oxygen sensor... more accurate than the sniffer. Plus you can leave it plugged in and drive the car while looking at the gauge.

    If you need more details, just let me know.

    John.
     
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  22. Martin308GTB

    Martin308GTB F1 Rookie
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    On the Countach, Lamborghini stuck to Webers until the arrival of the Diablo in 1990.
    Except a few 5000QV with K-Jetronic for the U.S. to meet regulations.

    Best from Germany
    Martin
     
  23. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    275
    Morning Brian,
    I like carburetors, sorry to disagree... just my opinion.

    John.
     
  24. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    275
    Don't want to be bad, but don't compare these American carburetors with Webers... I've played with both, can't compare.

    That's my opinion.

    John.
     
  25. Martin308GTB

    Martin308GTB F1 Rookie
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    #25 Martin308GTB, Apr 5, 2019
    Last edited: Apr 5, 2019
    John,

    introduction of the Bosch K-Jetronic did nothing desirable on the Ferraris. Remember the giant leap backwards with the introduction of the FI on the 2V-308s.
    It was the U.S.-regulations, what forced them to this design change. I would have preferred the Lamborghini Countach-way. Carburettors till the end of the 3x8 range and FI only for the U.S.-version.

    Best Regards
    Martin
     

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