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F40 Wastegate Adjustment

Discussion in 'Technical Q&A' started by red-riot, May 9, 2004.

  1. red-riot

    red-riot Karting

    Nov 14, 2003
    200
    Westchester, NY
    Full Name:
    Jon
    Preparing for the track I've pulled my Cat's and replaced with Tubi test pipes (The car has a Tubi exhaust). Under hard throttle but well under redline the wastegate pops and I loose all power until I release the throttle - quite alarming- it feels like I've got a limiter installed. My dealer is telling me that with the removal of the cats the operational characteristics of the wastegate is more binary - either open or closed. With the Cat's I've had similar episodes but not as frequent. The dealer said he has adjusted to match to the exhaust but it seems that maybe they haven't fine tuned the wastegate adjustments enough. Any suggestions would be helpful!

    Thanks

    Jon
     
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  3. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    2,167
    Berkeley, CA
    Full Name:
    Brian Brown
    Jon,
    How would you describe the wastegate "pops". Its sound more like you are having an overboost situation where the computer is seeing too much boost pressure and is shutting off the engine. What reading are you seeing on the boost gauge when you notice the power loss? Does it feel like the engine is hitting a rev limiter, like you head wants to hit the windshield when the "Power loss" situation occurs.
    The operation of the wastegate is controlled by a vacuum solenoid which is turn controlled by a the computer. It sounds like there may have been an overboost problem prior to the test pipe installation that was exaserbated by the less restrictive test pipes.

    Brian
     
  4. red-riot

    red-riot Karting

    Nov 14, 2003
    200
    Westchester, NY
    Full Name:
    Jon
    Brian,
    I think you hit it on the head, the boost gauge is showing 22 lbs - It feels like the engine is hitting a rev limter - shuts down and then reactivates when the boost comes under control. Can you recommend a course of action?

    Thanks!

    Jon
     
  5. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    2,167
    Berkeley, CA
    Full Name:
    Brian Brown
    Early turbocharged cars (288 GTO for example), used just a mechanical wastegate to control boost pressure. The wastegate is just a valve that is connected to a diaphragm which is forced closed by a spring. Boost pressure from the intake manifold acts on the diaphragm, against the spring pressure. When the boost pressure overcomes the spring force, the valve opens up and dumps the exhaust that would normally feed the turbos, thus keeping the boost pressure from getting any higher. The adjustment on the wastegate changes the preload on the spring. Turning it in raises the preload on the spring which raises the maximum boost pressure.

    On the F40, the boost pressure signal to the is altered by a soleniod valve that is controlled by the 1/4Cyl. fuel injection brain. The wastgate is set to open at some value that is less than the maximum boost pressure (Ferrari doesn't specify what it is, only that you should never tamper with it!). The computer can then modulate a boost pressure that is higher than this value to open the wastegate when its programming dictates (for example: decrease boost if detonation is detected). There should be a fairly good description of the system function in the factory owner's manual if memory serves me right.

    Most likely the problem is mechanical: waste gate valve stuck closed, waste gate diaphragm ruptured, pinched/plugged hoses to solenoid valve or wastegate, defective boost pressure solenoid valve.

    You could take pressure readings before and after the solenoid valve, in order to see what pressure is being applied to the wastegate. The wastegate function can be checked by applying a source of regulated compressed air to it, in order to determine what pressure it will cause it to open.

    You might try contacting Tony Palladino http://www.modena-motors.com/
    He is a Tubi distributor with a fair amount of F40 experience.

    Carobu Engineering http://www.carobu.com/ have worked with modified F40's on the dyno, so they might be able to steer you in the right direction.

    Good luck!
    Brian
     
  6. zsnnf

    zsnnf Formula 3

    Sep 11, 2003
    1,877
    What RPM is this happening at? I believe there is a fuel shut off at 7700rpm.
    22 lbs of boost is alot. Does the red overboost light come on when this happens?

    Rick
     
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  8. Bertocchi

    Bertocchi Formula 3
    Consultant

    Jan 28, 2004
    1,851
    New Orleans, LA
    Full Name:
    David Castelhano
    I recall that the internals of the US & european waste gates are different. After dismantling the wastegate the aluminum spring seat can be machined to the same dimensions as the Euro gate. Lower back pressure tubi longs for the Euro waste gate configuration. I'll dig through my notes and see if I still have dimensions. This was en vogue ten years ago!
     
  9. servidio

    servidio Rookie

    May 9, 2004
    5
    Servidio
    Full Name:
    John
    Does the car backfire when this happens? Any smoke released? I have a twin turbo car, and when I removed the cats, the boost became uncontrollable and the same thing that you are describing happened to me. My wastegates were stuck closed. Im sure yours can be pressure checked the same way mine were to tell if that is indeed the problem.
     
  10. red-riot

    red-riot Karting

    Nov 14, 2003
    200
    Westchester, NY
    Full Name:
    Jon
    Thanks David, I've heard that this might be the issue, let me know if you find those notes!

    Jon
     
  11. red-riot

    red-riot Karting

    Nov 14, 2003
    200
    Westchester, NY
    Full Name:
    Jon
    Rick,
    No overboost light, and it hits way before 7700 RPM

    Jon
     
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  13. red-riot

    red-riot Karting

    Nov 14, 2003
    200
    Westchester, NY
    Full Name:
    Jon
    Thanks Brian, I'm going to reach out to Tony and see if he can offer some suggestions.

    Jon
     
  14. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    1,572
    Kalamazoo, MI
    Full Name:
    Rob Schermerhorn
    David's right on with a good fix, modifying the waste gate. I concure with other recommendations such as Tony, too.

    Here's what's going on:

    You've reduced exhaust system pressure. Turbo systems are very sensitive to exhaust presure (a.k.a. back-pressure). You're hitting the overboost protection at 22 psig (pound per square inch guage, as opposed to absolute, which would be 37 psia, adding atmospheric pressure (confusing, isn't it?)).

    Overboost protection is very violent, as it kills the fuel delivery instantly. You go from full-throttle, 500 hp to zero power in less than a second, ouch.

    The key to modified exhausts on F40's is tuning the wastegate, like David recommends. It must begin opening sooner (beleive it or not...), and machining the internals reduces the spring pre-load, giving a progressive release of exhaust system pressure to the turbos, and giving you all the power and drivability you need.

    Simply backing out the adjuster is not enough, must be modified internally.

    An unmodified, stock exhaust F40 exibiting this problem can be fixed without internal wastegat modification. Some owners in cold climates will hit the fuel shutoff due to very dense, cold winter air.

    Do not remove the plastic solenoid valve(it changes it's duty cycle time, modifying the signal from the intake manifold to the wastgate), as it's there to flatten the torque curve of the engine, more boost at lower rpm, less boost at higher loads and higher rpm (win/win).

    This solenoid valve can also be adjusted on the car as fine tuning to an F40 which may still be overboosting after wastegate modification.

    BTW, don't run over 22 psig, the fuel shutoff is there so you don't run too lean and burn a piston.

    More boost is possible with modified computers or aftermarket engine management. 800-900 hp is certainly possible with some heavy duty modifications.

    Best regards,

    Rob Schermerhorn

    ps, I have the modified specifications, too. If you like, you can ship the wastegate to me for adjustment. Send me an email if you'd like to pursue this, and I'll confirm. I'm certain Tony or David can help you too.
     
  15. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    1,572
    Kalamazoo, MI
    Full Name:
    Rob Schermerhorn
    BTW Jon, Tubi and no catalyst may be too loud for Lime Rock. What tracks do you run?
     
  16. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    1,572
    Kalamazoo, MI
    Full Name:
    Rob Schermerhorn
    Not true. The only way to achieve this is with a high flow, heavy duty solenoid valve, computer controlled that puts pressure on the diaphragm in the wastegate to keep it closed, then releases pressure quickly at the set-point to snap open the wastegate. HKS and other manufacture such a system, but they don't flow nearly enough volume to handle the F40.

    On an F40 or other turbo car, the wastegate is cracking partly open well below it's maximum setting, which is why the computer controlled systems are popular with the import tuner crowd: you keep all the boost until max boost is achieved.

    Rob
     
  17. Steve

    Steve Formula Junior

    Nov 1, 2003
    901
    Seattle, WA
    Full Name:
    Steve Jenkins
    The guys at Carobu said NOT to mess with the wastegate adjustment. I have the new LM chips they produce here, and I have the LM Turbos with Tubi Sport Exhaust and the cat-bypass mufflers (not straight pipes, but no cats in their either from what I understand).

    My stock chips give me the same power loss at full boost. I'll report what I find when I put in the new chips today.

    Steve
     
  18. red-riot

    red-riot Karting

    Nov 14, 2003
    200
    Westchester, NY
    Full Name:
    Jon
    Gee Limerock is about 50 minutes away, funny my F40 seems without Cat's seems quieter then my 355 with Cats and Tubi's

    Oh well I'll let you know if they bump me from the track!

    Jon
     
  19. red-riot

    red-riot Karting

    Nov 14, 2003
    200
    Westchester, NY
    Full Name:
    Jon
    Thanks Rob, look for my PM.

    Jon
     
  20. Steve

    Steve Formula Junior

    Nov 1, 2003
    901
    Seattle, WA
    Full Name:
    Steve Jenkins
    I put the chips in and went for about an half hour test drive today.

    Keep in mind that this car is new to me anyway, so I won't have really specific feedback until I get the car on the dyno with both chip sets (and I may take all the exhaust bits and test that, too). My only experience with the car is as delivered, which is stock chips, LM turbos, Tubi muffled cat bypass tubes, and Tubi sport exhaust.

    With the LM turbos and stock chip, I seemed to hit max boost (and get the same instant power drop) way before I hit redline. From my limited testing today, it seems that the chip fixes that. The boost seems to come on slightly more gradually at lower RPMs, and then really kick in up to redline.

    I'll have actual HP and Torque curves when I take the car to the dyno. The Microsoft Game Studio sound lab wants to record the F40 on the dyno for an upcoming video game, so they give me some free dyno time and reports as compensation.
     
  21. red-riot

    red-riot Karting

    Nov 14, 2003
    200
    Westchester, NY
    Full Name:
    Jon
    Thanks for the info Steve, its great to see you loving the car, I remember how excited you were when we met at Cavallino!

    Jon
     
  22. robiferretti

    robiferretti F1 Rookie

    Oct 31, 2003
    3,252
    NYC area
    Full Name:
    rob ferretti
    Is it possible to revert back to a mechanical waste gate instead of the elctronic one?
     
  23. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    1,572
    Kalamazoo, MI
    Full Name:
    Rob Schermerhorn
    The stock F40 wastegate system is mechanical with a solenoid to assist by bleeding the signal to the wastegate at low rpm to improve response, then bleeding less flow above the torque peak to avoid overboost. Only the solenoid is computer controlled, open loop.

    This works well. Disable it, and lose lower rpm power a bit. Replace it with something else, and unless you're guided by an expert, you're on your own.

    Not to be confused with more modern systems which do monitor various pressures throughout the system to improve response and power.


    Best regards,

    Rob
     
  24. Steve

    Steve Formula Junior

    Nov 1, 2003
    901
    Seattle, WA
    Full Name:
    Steve Jenkins
    Are you sure? Page C6 talks about all the sensors in the F40 ignition system, and says:

    "- Boost pressure control valve: This controls the opening of the wastegate on the basis of engine rpm and the absolute pressure in the inlet plenum chamber; it is controlled by the right-hand management unit (bank 1-4)."

    On page C9 it says:

    "The wastegate is controlled by the injection control unit of bank 1-4 via a solenoid valve. The system is adjusted to obtain the maximum boost to coincide with the maximum torque zone. The control unit operates in such a way as to obtain, for every engine speed, the optimum boost for obtaining the maximum possible performance."

    Sounds electronically controlled to me!
     
  25. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    1,572
    Kalamazoo, MI
    Full Name:
    Rob Schermerhorn
    Steve, the manual and I are saying the exact same thing. Only I don't have to translate from Italian to English first. (...what's a "flanbloc"?...:))

    Rob
     
  26. Steve

    Steve Formula Junior

    Nov 1, 2003
    901
    Seattle, WA
    Full Name:
    Steve Jenkins
    Cool - good to know. At least it wasn't originally written in Japanese and then translated to English. I imagine it would look like this:

    "Please enjoy wastegate for to be acted upon by bank of injection control valving 1-4 solenoid. Everyones system happily adjusted obtaining therefore boost fully matching torque at top. With regards to operates unit for to contol ways at speedy engine all prime boosted and enjoying performance at your fully best smelling."
     
  27. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    1,572
    Kalamazoo, MI
    Full Name:
    Rob Schermerhorn
    I received this PM recently:

    I have repaired a few F40s via tuning the solenoid valve located on the passenger side rear shock tower. Background: the wastegate itself is set for about (memory here, not my old notes) 7psig. Ferrari specification is for maximum of 1.1bar (15.95 psi) manifold pressure. Exceeding an amount somewhat greater (can't remember) triggers ecu fuel shut off (and a major shock to the driver). This may occur only in cold weather due to ambient pressure being greater.

    So here's the deal, turbo spools and increases manifold pressure way above atmospheric, say nearly 30psia or 15psig (assuming the weather that day is 15psi or about 29.92 inHg). The solenoid valve is a variable duty cycle valve controlled by the ecu. When it's full open it's venting manifold pressure to the atmosphere via the one fitting connected to nothing. Full open reduces the pressure the wastegate diaphragm sees. Remember, wastegate is set to around 7psi. It really is a simple, robust and effective system, allowing a bump in lower rpm torque and bleed at higher rpm for a nice torque curve.

    Here's how to tune the solenoid valve. Holley carburetor jets. Thread tap fits perfectly into the open fitting on the solenoid valve. Now you're tuning the amount of bleed, effectively allowing additional manifold flow to reach the wastegate. Now the wastegate is opening properly, the manifold pressure is not exceeding the fuel shut-off threshold.

    Simple and effective. Sorry I can't remember what jets I've used, the information is buried in a file cabinet somewhere.

    Best,
    Rob
     
  28. 335s

    335s Formula Junior

    Jan 17, 2007
    865
    SF Bay Area
    Full Name:
    T. Monma
    Michelotto advised a boring of a hole by- first .5mm, then to 1.0mm oversize...based on resultant effects.
    Not to exact, really....and the results were ineffectual...in truth....

    The overspooling, when cold, was a specific problem for Northern California cars(a new car being delivered to the owner, was wrecked as a direct result of this peculiarity in the boost control circuitry), and the condition was actually discovered by the Ferrari rep. utilizing a piece of cardboard over the radiator to raise the coolant temp(look at the variables in the partial differential equation which drives the fuel mapping-it is in the WSM plain as day).
    Man in MI is correct here...

    Additionally, in 1990 there was the bad rap which "early cars" got for having "bad turbos"-bupkiss!
    Most of this urban legend originated from LA, and was a result of early TUBI installs and the lack of understanding of the relatiionship which backpressure plays in all of this... and the criticality of the RATE at which the spooling pressure is bled off.
    The rate of the rate...a second order differential equation...
    The other guy is correct here...

    The cure lies on a lathe....plain and simply.
    Measure twice-cut once..read on...
    David is correct here as well...
    It is unlikely anybody is going to publish a trade secret which is part and parcel an intrinsic aspect of the hotrodding of an F-40's job /work order.
    This is not an insignificant sum....
    Additionally, if one were to get this information, and it was not "the whole story," and the engine burns a valve(s), or "holes" a piston...
    ughhhhh....bad feelings all around...to say nothing of near certain litigation!


    I promise you, you are getting most of-but by NO means ALL- of the story here....there are no easy, and SIMPLE answers here....examine your 288 parts books, your EARLY EURO/not-catalyzed version parts books, early EURO/catalyzed, and late USA/EURO-catalyzed parts books, and ALL WSMs...detailed conclusions will become apparent to you.
    While things are close/similar-they are NOT exact.
    BE CAREFUL....
    Feel free to PM me, e-mails are free!
    I've done this sort of thing before....and honestly, I don't advise this for a street car.
    PS-MOST importantly, if you are doing to the car, what I think you are doing to the car....the BRAKES are whoafully insufficient-there is a BOLT on,
    FERRARI OE solution here as well....
    CIAO!
     

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