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Throttle response

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

  1. Martin308GTB

    Martin308GTB F1 Rookie
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    #51 Martin308GTB, Apr 7, 2019
    Last edited: Apr 7, 2019
    Brian,
    the GTI Mk.II 16V was s serious competitor against the 2V-308. Especially US-versions. Though only having 136hp and acceleration from 0-100km/hrs. in 8,5 seconds. And since this thread began with 'throttle reponse'... this is what makes the lively feel of an engine. Regarding throttle response the Golf made the 2V-i-308 look lame. But even the 1,6 Mk I with 110hp excited me, how it revved freely and fast from idle to red line.
    How US-cat-cars performed I don't know, because cats were not common over here, when these cars were new. Cats and emission management became popular here not earlier than in the mid- to late 80s.
    Back in 86/87 folks still preferred to order their new ride without cat, since gas stations with leadfree gas were still rare :)

    But like mentioned previously, smg's explanation further above about the different distances -and very long on the Ferrari- inside the induction tract convinces me, why some engines perform lazy and others lively with the same FI-system.
    Sorry, but the situation, that Ferrari didn't make the most of using the K-Jetronic, like others did, disappoints me. This doesn't suit Ferrari well.

    Best Regards
    Martin
     
    Brian A likes this.
  2. dave80gtsi

    dave80gtsi Formula 3
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    Perhaps so, but the OP's point is to try to improve throttle responsiveness, not necessarily to create more low end power.

    One of the most 'fun' cars to drive which I have ever owned was a 1300 cc X1/9 with a flywheel lightened to roughly 80 to 85% of the stock flywheel's weight. Certainly an engine with hardly any power, low-end or otherwise. And while lightening the flywheel by 'only' a couple of pounds certainly does not sound like much, the end result was a little engine with lightning quick revability - Quite entertaining!

    DM
     
  3. mike996

    mike996 F1 Veteran

    Jun 14, 2008
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    I suggest the OP does the timing change I mentioned. It costs virtually nothing - maybe 30 minutes of time, a foot or two of wire and a couple of common connectors. It will provide some improvement in low end throttle response he's looking for. There is no physical modification to anything - simply a piece of wire with a connector on one end to an existing terminal on the microplex and the other end attached to any handy body screw (for the ground).

    Again, he would have to check to be sure WHICH terminal needs to be connected to ground but that information is available here with a search. In fact, back when I decided to do it, it was RifleD that provided the info regarding the appropriate terminal connection(s).
     
  4. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    287
    Morning Martin,
    I agree, K-jet is ok...I prefer carburetors. Since mine is a 328, not many options (none), and it's a US model :(

    John.
     
  5. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    287
    Morning Mike,
    Is there any way you can point out what wire you grounded?

    John.
     
  6. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
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    Morning, is your car US specs?
    If not you have a little more work that has to be done , like welding a bung on the muffler.

    John.
     
  7. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    287
    Ok, the innovate gauge measures is air/fuel mixture. It displays parts of air per parts of fuel...ideal would be 14.7 to 1 at idle and with worm engine.
    Now here is how to hook it up: disconnect the original oxygen sensor feed to the computer(black wire from the sensor which connects to a green wire). This will leave the computer without a feedback and the metering valve will cycle at a constant duty cycle.
    The gauge has many wires, ignore all and use only the red and black ones. Red to positive, black to negative, use extension wires and alligator clips, connect directly to the battery.
    Connect to wide band oxygen meter with extension supplied in the kit...follow instructions and calibrate in open air.
    Now remove original O sensor and install the wide band, start the engine, allow for the sensor to worm up. It will start giving a reading... above 14.7 is lean, below 14.7 is rich. It should be around 14.7 to 15.
    If it's not you have to adjust it, that is done on the air box, where the fuel distributer is mounted. There is a plug, when you remove the plug, you fit a 3mm hex wrench down the hole(it has to be a long hex wrench). Clockwise richens the mixture, counterclockwise leans it. Adjust in very small increments and plug hole with your finger(if you don't you'll have an air leak), hit the gas a throttle a couple of times, watch the needle, repeat in either direction until you manage to get it in the margin.
    If fans kick on, wait until they stop, this affects mixture. Once achieved, plug hole, remove sensor, install original one and reconnect wiring.

    Any question, please ask.

    John
     
  8. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    287
    Sorry...Try to keep it between 14.5 and 14.7, don't go on the lean side. If you can keep the needle in that range, when you replug the original sensor, idle will be super steady and throttle response will be as good as it can be...It ain't gonna burn rubber, unless you "slip" the clutch a little and let the engine rev up...but that's a bad practice on an already "factory weak clutch design"

    Hope this helps.

    John
     
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  9. mike996

    mike996 F1 Veteran

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    John, unfortunately, the car is not here at the house so I can't take a look to see which connection is involved. It will probably be another week before I can pick it up at the storage garage where we keep it when we are not in town. I'll try to search here to see if I can find the discussions when I did this. In trying to think hard (which is hard in itself!) I'm now unsure as to whether I ADDED a ground or REMOVED a ground to get to the Euro setting. Today I seem to recall that a ground from terminal 17 is how it came "from the factory" which is was what makes it into a US curve and removing the ground switched it back to the "standard" (Euro) curve. It was all quite clear 10 year ago! ;) I'll try to dig up some info.
     
  10. Saabguy

    Saabguy Formula 3
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    THANKS!

    Lester

     
  11. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    287
    Thanks Mike,
    No rush, I was looking at the wiring diagrams and the US model (mine) has 14 pins used and the European has 12.
    Not that my car ran bad, but if something simple changes the performance, I'll try it out.

    John.
     
  12. mike996

    mike996 F1 Veteran

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    Well, if there are only 14 terminals, clearly my "recollection" re pin 17 is not to be trusted! :)
     
  13. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    287
    Morning Mike,
    Just looked at the diagrams, Terminal 17 on the US model is grounded along with terminal 11. European model is only grounded on terminal 11.
    Think we're getting to a point:) Thanks!!!

    when you get a chance, let me now for sure.

    For now I'm rebuilding my engine, so still have plenty of time before I start it up.

    John.
     
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  14. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    287
    Afternoon Brian,
    As said before, I live in Spain, the only mod allowed is changing body color. Besides from this, which is a legal issue, if you modify the car in any way, like adding modern FI or upgrading the engine(probably would not be detected on an inspection), the resale price on the car goes down the drain.
    Buyers want the car "original".
    Don't know about the rest of Europe, but here in Spain, that's pretty much the game. Apart from what has already been said, resale prices are higher in Europe than in the States, so if I ever sale, it would be in Europe

    Just a comment,

    John.
     
  15. Martin308GTB

    Martin308GTB F1 Rookie
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    John,
    I think the crux of the matter is, that the 3x8 cars are meanwhile much more considered 'classic cars' here in Europe, than in the U.S. Look at that mangled 308 GTS from that dreaded 'purists beware'-thread. Can you imagine something like that here?
    O.k., we had the 'Koenig-Specials' for a while, when our cars were new. A similar sin. But Ferrari banned them from putting the Cavallino onto their cars. Though there are meanwhile many others, who mangle brandnew Ferraris too. But no old ones. Imagine any 365 or 250 car with body kits or modern engine electronics.
    But some day, when the cars are even older, than they are today, they will also become classic cars across the pond and this will be probably the time, when folks begin to tear off all modifications, they had done in the past.
    Ten years ago I planned to upgrade my A/C with a well performing retro system from the U.S. But I cancelled the idea, because I began to wish keeping my car original and rebuilt my old system instead. Tore off my QV/512BBi-mirrors, which offered great visibility and installed original Vitaloni Californian with poorest visibility :)


    Best Regards
    Martin
     
  16. Rifledriver

    Rifledriver Two Time F1 World Champ

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    Thats the reason I support buying fuel injected cars. Carburetors are fine for cars of the 50's.
     
  17. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Two Time F1 World Champ
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    I was toying with the idea of removing the L-Jetronic on my 82 Alfa Spider for Webers. I thought this plus the appropriate cams may wake it up a little.

    Bad idea for a car I just play with?
     
  18. Martin308GTB

    Martin308GTB F1 Rookie
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    In my humble european opinion it's a great idea. If from time to time a 115-Alfa finds its way from the US to Europe, first thing is to get rid of the FI -especially if it's a SPICA- and throwing a pair of Webers onto the engine.
    But look, that you can get a pair of decent 40DCOE Made in Italy (Weber Bologna) and not the spanish repro junk.

    How does the L-Jetronic work? Maybe it's no issue where you live regarding climate, but when I owned a daily driver with L-Jetronic, I had to replace the warmup-regulator almost every year in fall, when temperatures dropped.

    Best from Germany
    Martin
     
  19. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Two Time F1 World Champ
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    I bought the car in Nov 1996. I have never touched any part of the FI system other than to change the filter. It has been flawless, just like the K Jet on my 1980 Scirocco. It has never had an FI problem and I have had it since 1985. Nothing on them seem to break. Even my 308 has never needed FI parts service since I have owned it for the past 22 years.

    I only wanted to change the Alfa just to have something different. Really no other reason.
     
  20. Martin308GTB

    Martin308GTB F1 Rookie
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    You're lucky. Or it is always warm enough in AL for never needing the warm up device. The warm up regulator for the L-Jetronic -correct: auxiliary air valve- is slowly getting rare and expensive.

    Best from Germany
    Martin
     
  21. smg2

    smg2 F1 Veteran
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    Weber's are great, however they are not a set and forget. They will require fiddling with regularly or periodically but nonetheless they are time consuming.
    If you were asking about going from CIS to Weber's an argument could be made, but L-jet is EFI, you are much closer to stand alone fully programmable EFI that would be better then shifting back towards carbs.
    The constraint with L-jet is the flapper mass door, modern EFI uses either TPS, speed density, mass air density or combinations of them.
     
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  22. Aircon

    Aircon Seven Time F1 World Champ

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    This! My EFI conversion on my glass car is awesome. Throttle response of the carby car (and still the same carby noise, which the CIS cars lack) plus the clean running of the injection cars, and no washing the oil off the bores and it's actually pretty hard to pick it by looking at the engine bay too! Also, it would take 1-2 days to convert back to the carburetor.

    If I had a CIS car and I wanted to improve it, the ONLY thing I'd consider is throttle bodies and EFI. Better response, better running, better sound...what's not to love?
     
  23. oelboxer

    oelboxer Karting

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    Matt Wright
    Lots of great info here, but here's my off-point comment: Rifledriver, you said you tuned a 6.9 with Ron Iskanderian? That's a legendary day if every there was one. Thanks for offering so much info and insight to the board. - Matt
     
  24. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    287
    Morning Martin,
    Just my point of view on Webers, IMO probably the best, now... the first popular cars that came out in Spain with 2 double carburators were the Fiat 1600 twin cam 124 Sport.
    These used the original Webers (Italian). At the end, everybody finished swapping these Webers for a single carburetor. Reason behind this was that you always had to adjust them to run correctly, let's keep in mind that that we're talking about an every day used car, not a weekend toy.
    I bought a set of these carbs in the mid 80s and placed them on a Fiat 131 Supermirafiori, which had the same engine. Not hard to adjust, but always needed adjustment. Same as before an every day car.
    Later in the late 80s, Alfa came out with the 33...water cooled boxer engine with 2 double Webers. At first they sold like doughnuts, and vanished just as fast.
    Salvage yards were full of them.

    Over here when you're trying to buy a 308, 90% of buyers want the GTSi, everybody walks away from the carb cars.

    I like carburetors, don't get me wrong, yet to an average driver who knows little or nothing about mechanics, multi carbs can be a PITA.

    K-Jets have been very successful, reliable and bullet prove...very little to no maintenance, just turn the key and you're gone.
    Mercedes, BMW, Ford, VW, Audi and Porsche used them for years and years...no complaints.

    Now the K-Jet with Lambda, made for the US market is a little different, The lambda sensor was a "patch" to comply with US emission regulations.
    Worked(not very well), but it was the only way back then to cover that market.

    As said before, this is my opinion, not an argument. Everyone has the right to spend their money as they wish.


    John.

    BTW, I've had Seats (Fiats licensed in Spain) with "Spanish" Webers...damn good carburetors.
     

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