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Upgrade or Stock?

Discussion in '308/328' started by dave80gtsi, Jan 14, 2023.

  1. mk e

    mk e F1 World Champ

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    You can install the 76/77 cams and intake.

    You can install 76/77 cams or hot aftermarket cams and convert the intake to EFI.

    Either will get you 76/77 performance or better.

    Beyond that more compression is good, 10-11:1 depending on you cams. Flow work is good. ITBs are good. displacement with bigger bore and/or 348/355/360 crank is good. This is how you go past 76/77 performance and stay NA....forgot the V12 swap option, that's good too.
     
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  3. mk e

    mk e F1 World Champ

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    I have a decent engine simulation program (dynomation 6) and can run options if I know what exactly the question is. It has a very good library or turbo and superchargers so this blower on that engine is pretty easy. 8.8 vs 10.5 compression is easy. It gets harder when more things get custom....but if there is a specific question I can run it.
     
  4. Ferraripilot

    Ferraripilot F1 World Champ
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    Yeah carbs bumped to 34mm chokes. Really had to back off the air correctors down to around 155 if I remember right, main jet was 135 or thereabouts. LOTS of signal to the carb, I probably could have gone even larger on the chokes but it drove perfect and the a/f ratios were spot on. 10.4:1 compression or so.

    No mods to get that much lift needed. I want to say anything above .435 or so needs a valve guide mod and obviously different valve springs and anything with more than .380 or so lift needs different springs, which I also changed to some I found in Australia that were perfect for the lift and sat at 85lbs seat and 230lbs over the nose. Stock springs are somewhere around 65lbs seat...?
     
  5. mk e

    mk e F1 World Champ

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    I thought there was a risk of flipping shims out above .360 lift, but maybe that is a QV thing? or maybe the lobe design thing? Either way I did a shim under conversion believing I needed to.

    I know its blasphemous to disparage webers but I think generally if they are small enough to run good you end up giving up roughly 10% off the top hp wise, maybe 5% in race trim meaning just live without anything below 2500-3000 or so. There is a simplicity to carbs but I just couldn't go back to the limits they impose.
     
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  6. mk e

    mk e F1 World Champ

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    Found the video, old and low quality but it 308QV with eaton mp90 blower at 10psi
     
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  8. mk e

    mk e F1 World Champ

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    Here it is with a lysholm ax2300 blower at 24psi at the autocross. Sound is bad but there is a short stray at the end with decent sound, it whines.
     
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  9. smg2

    smg2 F1 World Champ
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    For both 2V & QV the stock inner valve spring will bind at 11mm lift. 10.5mm is really pushing it.

    Spitting shims, bigger issue for QV due to smaller base dia. Don't have the numbers off hand but lift and duration beyond P6 is sketchy on stock parts.

    There's more to it then just lift though, stock spring harmonics, valve train weight, jerk, acceleration etc.. so while you can stuff more aggressive cam lifts, it's best to look at the entire train and see the harmonics to avoid other issues. Shim under sheds a huge amount of weight and stress.
     
  10. dwhite

    dwhite F1 Rookie

    Does Kieth Martin feel the same way about a 250 SWB. Too slow to drive now, as you may be embarrassed by a Toyota Camry, right.

    Keith Martin has nothing new to speak about. His relative time has come and gone, so he tries to be provocative.

    I really would never change my 308QVs engine as it works great as a single package. As many have said, if you don't like it, buy something you like.

    There so many stupid fast cars for far less than a 308 costs, if that's your mission. I have a 2013 corvette convertible 427 modded and it's stupid fast cost me 53K two years ago with 6,800 miles. I still love driving my 308 as it is.
     
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  11. peterp

    peterp F1 Veteran

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    #84 peterp, Jan 24, 2023 at 9:04 PM
    Last edited: Jan 24, 2023 at 9:11 PM
    I agree with all of your post, but the subject of this thread is the engine in the 308 GTSi/GTBi and also in the Mondial 8. That engine was down on power, even in period. The carbed version of that 2-valve-per-cylinder engine was fine; however, it was not fine once they went to fuel injection to meet emissions.

    To your point, I absolutely loved my Mondial 3.2 -- thought the engine was perfection and didn't need any more power. The GTSi/GTBi/Mondial 8 engine? It does need more power to fully enjoy the car in my opinion/experience.
     
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  13. peterp

    peterp F1 Veteran

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    144p video quality!! :eek::eek: oof! :)

    Hard to get a feel for the power on the course, but that burst of acceleration at the very end is impressive. The whine doesn't sound annoying on video, but I guess that might be the case in real life. My brother's modified Mini had a supercharger, and it was a hoot to drive, but the supercharger whine could be a bit intrusive.
     
  14. mk e

    mk e F1 World Champ

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    Yes, old and low quality but it does show a couple things.
    1) Under power it sounds like a turbine very noticeable at the end. Its a taste thing though, I just though with all the blower talk hearing one might help.
    2) as you pointed out, it frikin accelerates, it was putting 500+hp to the wheels at that time. Another 308 owner who popped over for a ride described it as "it doesn't accelerate, it launches".
    3) Most importantly it drove just fine and it won it's class that day on quite a tight course. There really is nothing to comments about 308s losing their balance when hp goes up...more hp just means the car accelerates faster and you need to treat it with more respect. But its still drives like a ferrari.

    I get that most people want their cars stock and agree that for most people that is for sure the best choice, but a high hp 308 is a frikin ball to drive is all I'm sayin :D
     
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  15. sherpa23

    sherpa23 F1 Veteran
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    #87 sherpa23, Jan 25, 2023 at 7:34 AM
    Last edited: Jan 25, 2023 at 7:54 AM
    I have a dry sump carbed 308 2v motor with almost 300 hp (298 hp). It was built by Steve Moody in the UK. I think his company is called SMDG performance.

    It had high comp forged pistons (10.5:1), Ferrari 348 conrods, “fast road” cams from Superformance and bigger chokes and jetting in carbs. Heads were skimmed and ported. New liners too as the pistons are slightly oversized.

    I am running Nick’s XDi ignition now but initially it had the old Pertronix from a single distributor.
     

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  16. mk e

    mk e F1 World Champ

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    It looks like there is quite a lot more than engine work going on there

    What does it weight?

    More importantly, how's it drive?
     
  17. Ferraripilot

    Ferraripilot F1 World Champ
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    That's mighty impressive from a 3L 2v engine with carburetors. Any dyno sheet?
     
  18. mk e

    mk e F1 World Champ

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    Here's some info on the 3.2 build I mentioned

    https://www.ferrarichat.com/forum/threads/mondial-3-2-with-weber-carbs-reprise.26761/

    I was remembering a cam swap and 310-320hp but this says stock cams and 285ish hp....but I remember it was all designed for a mild cam swap, we were talking about like the 76/77 ferrari cams around 230-235 deg @.050 but I'm remembering an issue with the grinder and maybe that never happened.

    CIS off, cars on, mild porting, 20rwph gain but it was ready for cams which would add another 20-30 I'm certain.
     
  19. mk e

    mk e F1 World Champ

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    #91 mk e, Jan 25, 2023 at 9:25 AM
    Last edited: Jan 25, 2023 at 9:32 AM
    found more, cams did change

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  20. smg2

    smg2 F1 World Champ
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    Flame suit on...
    17% loss is crazy high.. I've Dyno run the engines and chassis enough times to see a 10-12% loss. There's no real fixed number as the variables are too many. But that's the range I've personally seen.
     
  21. mk e

    mk e F1 World Champ

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    On a 308? engine dyno vs dynojet? Numbers I've seen for most stuff are around 15%, but 17-18 on the 308 with the drop gears in the mix

    Hub dynos it a bit different as they don't have tire losses so I guess I need to hear more details????
     
  22. smg2

    smg2 F1 World Champ
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    Super flow engine Dyno and dynojet 48" inertia roller. Engine setup and running first, then drop in and chassis run, then finally road tune.

    I've not done this with minor mods like cams,efi etc.. this is for big bore builds and heavily modified builds with boost. Power development and efficiency change.

    It's still a rough percentage and not at all linear. Apples and oranges.

    I don't like chassis dynos personally, way too many variables to fudge numbers, then there's the lack of proper air flow, cooling etc.. road tuning is best post engine Dyno.
     
  23. mk e

    mk e F1 World Champ

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    Those are the gold standard units and data doesn't lie. The 17-18% number I think came from norwood way back when. Internet says like 10% for FWD, 15% for RWD but then dynomation default is 20% which I guess is rwd with older design auto trans?. A 308 is much like a FWD but does have the drop gears.....you could sell me 12% as a better guestimate and 90hp/liter closer to the real number for he engines I thought were 100hp/l
     
  24. Ferraripilot

    Ferraripilot F1 World Champ
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    Mustang dynos can fudge the numbers with variables. Dynojets cannot hence why I only ever use dynojets. The Germans have the ultimate in the Audi/BMW/Porsche/Mercedes developed MAHA dyno as it takes the guesswork out of it as it calculates with incredibly accuracy what the powertrain loss is, and even shows the powertrain loss curve at various rpm. The only MAHA dyno pull I've seen with a 308 showed about 42bhp was lost through the powertrain at 6500rpm, which was the rpm where it made peak power at the wheels. A flywheel dyno will show peak power at a higher rpm than a chassis dyno due to the constantly increasing powertrain loss with rpm. So an engine that made peak power at 7000 at the flywheel will likely show 6500 at the wheels.


    What's sort of bizarre to me is I can run far more aggressive cams on a 911 engine then on 308 engines. For example, the last twin plug 2.8L high compression 911 motor I build ran a DC60 camshaft, which is 265 or so duration @ .050 and .480 or so lift. That was a street motor and it was fine. Made 278bhp on 46PMO carbs @ 7800rpm. A 308 cannot run such cams on the road. Likely due to head flow issues.
     
  25. Ferraripilot

    Ferraripilot F1 World Champ
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    You should see the drivetrain loss on a Gullwing Mercedes. I have a sheet here that shows a whopping 52bhp loss per the MAHA dyno. It put down 162.7bhp at the wheels otherwise. Engine was factory rated at 215bhp so it's right about on the money.
     
  26. LB427SC

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    I have a 2v GTSi also. I agree those cars would benefit from a little more power, ie as you say, bringing it back up to carbed levels as a basic, although I suspect the cost will be very high for a limited improvement.

    It seems that the power loss was due to a combination of reduced compression and/or less aggressive cams. I still can't find the reference but I do recall reading this was partly because Ferrari was concerned about ensuring smooth airflow past the metering plate. There is some logic in this. Injection should not reduce power, certainly not by approx 15%. OK Bosch K is hardly advanced but neither is a carby!

    If the above is the case then reversing the cam/compression changes may create the exact issue Ferrari was trying to avoid? I imagine that's partly why they respond well to forced induction, because its fairly smooth airflow and overcomes poor breathing. The P6 cams look to have a very large overlap, almost race engine levels, so adding those might cause some issues.

    I'd be really interested to know if anyone has simply added these cams to a 2Vi engine and it worked ok. It may be Ferrari was being over cautious, FI still being a lot newer tech back then.
     
  27. mk e

    mk e F1 World Champ

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    The CIS system used a mechanical Mass Flow Meter that has 2 issues if hp is your goal. First gets is power to operate from the energy in the air stream...it eats about 20hp. Second is that it can not tolerate reversion which limits how much cam duration and specifically overlap can be used, that is the other 20hp. so a 2v CIS is 200hp, and early carb 240.

    Ferrari tried to address this by going to the QV head. They use exactly the same cam design and port flow as the 2v but the 4v has more valve perimeter so more flow area is exposed quicker without need to add duration and its back to 235hp. But remove the CIS from a 4v and you have 260ish hp

    There was a company of 2 that were supplying a way to use an ECU to concrot the CIS...can't find them now though :(, but that would allow better cams with CIS. The other and more common option is to just fit electronic injectors to the CIS intake. Nick's has a bolt on kit I think for 2 or 4V intake conversion. I've done 1/2 dozen QV intake conversions over that years like this but this is a permeant change to the intake so converting back would mean getting a new set of runners. But once you go to EFI, you can run about any cams or blower or turbo you please so this works really well as part rebuild that is targeting higher that factory hp while keeping stock drivability. A few have also fitted motorcycle TB which have the injector, you need to make an intake but that is pretty straightforward as its just a flange with some tube welded or machined on and give a pretty car car look. There are also weber sized/looking TBs that a few here have done.

    The thing to remember though is once you change the cams, the only way to put the CIS back on is take the cams back out.

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  28. LB427SC

    LB427SC Rookie

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    Finally found the reference I read a while back. Copied here as there is some potentially useful and interesting info.... Some of the links no longer work sadly. the original post is from 2004 so some things may have moved on.

    Background
    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 (www.durable1.com) 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.

    Others
    To be complete, there is a whole Kjet system upgrade, the Lenz Motorentechnik(http://www.lenzmotorentechnikusa.com/LenzUSAHome.htm), 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 (www.elgincams.com) and Web-Cam (http://www.webcamshafts.com/) can speak to regrinding, but the stock overlap of 24 - 26 degrees is probably about it.
     
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