328 upgrade

Discussion in 'Technical Q&A' started by vittorio, Apr 19, 2004.

  1. vittorio

    vittorio Karting

    Nov 12, 2003
    Full Name:
    #1 vittorio, Apr 19, 2004
    Last edited by a moderator: Sep 7, 2017
    Hi, I'd like to have more HP from my 328.
    I have already upgraded the rear OEM exhaust box with a Tubi and installed K&N air filter but the result is.....better sound and no HP increase.
    My Official Ferrari service mechanic has told me that also installing the Tubi manifolds I cannot have Hp increases because the Tubi are identical (internal shape and lenght) to the OEM manifolds exept for the construction material and so.......nothing apart better sound.
    I've also heard about polishing intake and exhaust valve seals and ducts for better airflow to gain HP ?!?!?
    Anyone experienced with this upgrade?
    Any suggestion?
    Grazie amici
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  3. Ed P.

    Ed P. Formula 3

    Dec 28, 2002
    Long Island
    Full Name:
    No Longer
    CHeck out some of the threads and posts by member snj5 (Russ Turner). He has a 3.2 mondial with some really cool mods to increase hp.
  4. chaa

    chaa F1 Veteran

    Mar 21, 2003
    I looked into this for my 328 last year, and was told by Shiltec Ferrari that they offered two options. The first was a new fueling remap which would cost around £3,000 for an extra 20ish bhp, the second was the weber Alpha in jection system and head work that is fitted to a custumers race car that was in Auto Italia a few months back, trhis cost around £11.000 plus ish and would give 370 bhp. I do have there price list and spec sheets if you have any questions. I thought it was very expensive for the power gains so i just bought a bloody 355 spider, job done.For that kind of cash you could go Blower.
  5. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    Full Name:
    The upper limit on a 2V carb'd 308 is probably 320 - 330 BHP. 328 would be higher.

    Michelotto got around 370 or 380 BHP from the 308 LM with 4V heads and F.I. Weighing about 2000 lbs it was as fast as an F40 at most track events. Michael Sheehan discussed the car in a "best car for Vintage Racing for $200,000" thread on his site.

    Whatever you do is going to be very expensive (carbon fiber panels anyone...).
  6. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    San Antonio
    Full Name:
    Russ Turner
    Ciao, Amico
    Although I am going somewhat to an extreme with my 3.2 (carbs, cams) there are some other options for just the K-jetronic. Copied below is an article I wrote for 'the other board's 'Aftermarket Upgrades' section; hope this helps.

    The Bosch K-jetronic fuel injection system is a brilliant piece of mechanical fluid dynamic engineering that first appeared on German cars (Porsche, MB, VW) in the 70s and was adopted by Ferrari beginning in 1980 to meet ever tightening emissions standards. The thing to remember about this elegant bit of kit is that it was designed to primarily meet emissions regulations - it is NOT a performance fuel injection system. It's main problem from a performance point of view is that while it delivers stunningly accurate air/fuel ratios (AFR), the air must WORK its wat through a tortuous ducting system through a single throttle body after WORKING to lift the airmass flow sensor plate which otherwise BLOCKS the flow of air into the engine. In short, there is a lot of resistance to airflow. To complicate things a bit, the Kjet and Marelli ignition systems are wholly separate and do not talk to each other.

    Mods available
    Short of replacing the Kjet with Webers or Electronic fuel injection that both allow more AIRFLOW into the engine, Kjet mods primarily focus on decreasing resistance of the Bosch system.

    1. Tune the Kjet to factory specs. I know it's obvious, but the system is going to deliver it's best performance from a good tune-up from someone with an exhaust gas sniffer and setting the CO, which sets the mixture. When set correctly, the ability of the Kjet to deliver a constant AFR is amazing. While maybe not meeting emissions, the best AFR is about at 13.2 or so. Stock Kjet settings keep the AFR a round 14, or a bit more. We're not talking gobs of hp here between 13.2 and 14, but a couple - certainly not with the required mild specification cams required for Kjet to work well.

    2. K&N air filter. Everybody's got a differnt opinion about these re-usable high flow filters. I personally have seen them flow more air to the tune of about 5+ hp at high rpm settings on a chassis dyno and have 'heard tell' of close to 10 hp on a 328. I've also heard they don't do squat. Well, I've seen it with my own eyes and think they do allow more flow in the 5hp+ range, but nothing dramatic.

    3. Bigger throttle body. Ed Maszula (advertises in 'Excellence', the Porsche mag) will bore out your throttle body to allow less resistance at this point. Matt 'Kermit' Morgan who runs a Ferrari aftermarket shop ( specializes in this service for Ferraris and has flow benched a 10% increase in airflow boring out to 69 - 70mm and adding a new throttle plate. He will be dynoing to check results soon. While theoretical, there is a possibility with throttle body boring that a little low end responsiveness will be lost in favor of more top end, but will have to wait on some driving reports. I don't believe that drivability will take a big hit myself.

    4. That big ol' ugly serrated black rubber air hose that goes from the fuel distributor to the throttle body can't be good for flow. Durable1 (above) makes a smooth carbon fiber tube replacement to help airflow.

    To be complete, there is a whole Kjet system upgrade, the Lenz Motorentechnik(, a German system which adds an ECU that controls the Kjet through the frequency valve and replaces the Marelli ECU tying the two together with more aggresive curves. The system also comes with a new exhaust. They claim 300hp (DIN?) from a 3.2 Euro motor initially factory rated at 270. Well, I'm not sure I believe that, but I'm sure it helps some. Check it out and let us know. I think the whole thing is $3 - 4K.

    Cams - besides flow, the cam profiles in Kjet systems are very mild to prevent reversion waves that would confuse the airmass sensor plate. I would bet that the Ferrari cams are as aggressive as possible, although I know the Porsche community has experimented with grinds. Experienced cam folks like Elgin ( and Web-Cam ( can speak to regrinding, but the stock overlap of 24 - 26 degrees is probably about it.

    That's it for now. We haven't talked about exhausts, emissions systems or other ignition systems - will save that for separate posts. Please add on your experiences and new systems as you find them. The Ferrari V-8 is a great engine and a lot of fun and is even more impressive the more you get to know it thru little tweaks to help it do what it was designed to do in the first place!
    Hope this helps get folks started
    best to all
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  8. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    Without taking the engine apart, there is little HP that you can find.

    However, with the engine apart, you can install higher compression pistons, bigger cams, do a cleanup of the intake and exhaust ports; and thereby, find more HP, not a lot, but useful amounts. The benefit/cost ratio is about 1/100 as good as the ratio in American V8s.
  9. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
    Full Name:
    My vote: decrease WEIGHT!!!!!!

    Amazing how many people spends $$$$ on mods and use air filters that MAY actually allow more dirt into the engine, yet do not investigate LOWERING the weight of the vehicle. More Torque/HP is nice and all, yet lowering the weight (both unsprung and sprung) has MANY wonderful benefits over small HP/Torque "improvements" :)
  10. vittorio

    vittorio Karting

    Nov 12, 2003
    Full Name:
    Thank you all.
    Your advices have been very useful.
    Grazie amici

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