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Ferrari chassis dyno testing

Discussion in 'Ferrari Discussion (not model specific)' started by SteveB, Feb 24, 2004.

  1. SteveB

    SteveB Karting

    Oct 5, 2003
    62
    Puyallup, WA
    Full Name:
    Steve Barker
    Having just read the other thread about the ABC's of chassis dyno testing it made me wonder how many of you actually have had their cars on some sort of a chassis dyno.

    I have a DynoJet 248 in my home shop that I use extensively. I just sold my 360 Spider that I had for 3 years but never put in on the DynoJet. Honestly, I was too afraid of what I would find.

    I am interested in hearing about the cars and the numbers.

    Steve
     
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  3. 4sfed4

    4sfed4 Karting

    Dec 22, 2003
    231
    First off, you are a king in my book. A Dynojet in your home shop is something that commands worship.

    Second, I cant believe that for three years you withstood the temptation to throw that baby up there! I can barely stay away from the dyno and its 30 miles away and I have to pay for it each time!

    My guess is that on a Dynojet the 360 will lay down something in the low 300's. From whats I have gathered, Ferrari seems to be a tad optimistic in the power claims.
     
  4. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
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    Russ Turner
    There was a Norwood dyno day thread with several Ferraris from the old board:
    http://ferrarichat.com/events/dyno2002/

    A quick summary (rear wheel hp):

    308 gtsi - 175
    308 gts w/ 3.0 qv engine - 192
    328 - 210
    328 - 216
    328 - 218
    348 - 250

    There are several dyno threads where I posted on my carburetor conversion Mondial 3.2 development data, ending up with 232 rwhp (graph attached).
    Would love to see other dynos, especially with air fuel data if you have it.
    best
    Russ
     
  5. SteveB

    SteveB Karting

    Oct 5, 2003
    62
    Puyallup, WA
    Full Name:
    Steve Barker
    4sfed4, two of my cars that I dyno regularly make 607 rwhp and 1192 rwhp so you can see why I didn't want to be too disappointed with the 360.

    snj5, I can post you some graphs but I am not sure the data would be relevent to what you are doing.

    I am currently looking for an F40. When I get one I will definitely put it on the DynoJet and see what it does.

    Steve
     
  6. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    7,940
    I should just mention that the best gear to dyno on is the gear closest to 1:1.

    For the F355/360 this is 5th gear, not the 4th gear that is appropriate for Vettes, Vipers, Mustangs,....

    However, with that said, it is always instructive to do a dyno run through the gears 1st->2nd->3rd->4th->5th. The differences in the HP/TQ curves for the different gears gives you an indication of how much loss is occuring in the engine due to rotational inertia of the crankshaft and rest of the drive line.

    Another point is that a dyno is 3% accurate on the same car on different days at best with weather, gas, air pressure, temperature,...even after compensating for all these variables. Comparing 2 (or more) different cars on different dynos on different days is not much more accurate than rolling dice. In addition, the shape of the TQ and HP curves is much more important than the actual peak numbers off of either curve.
     
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  8. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
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    Russ Turner
    I think everyone would be interested to see what cars produce what curve shapes and numbers, even if not definitively comparable. If A/Fs are available, I'd enjoy watching what a computer thinks is the best A/F ratio and how tight it can keep it. :)
    rt
     
  9. GaryReed

    GaryReed F1 Rookie

    Feb 9, 2002
    3,093
    Seattle
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    Gary
    WOW!! Could you please tell us what model/make those two cars are that are cranking out those BIG numbers??
     
  10. SteveB

    SteveB Karting

    Oct 5, 2003
    62
    Puyallup, WA
    Full Name:
    Steve Barker
    Mitch, you are of course correct about using the gear closest to 1:1. DynoJet also has the ability to measure and graph "Negative horsepower". To quote DynoJet, "If drum deceleration was measured and graphed, we would be viewing negative horsepower. Negative horsepower allows you to view drive train losses and other parasitic losses." Where are you getting your 3% accuracy figures with regards to dyno runs made on different days? I am not saying that this is not a good figure, I am just wondering where it came from.

    snj5, the graphs I have are not of Ferrari's. If you don't mind, I would be glad to post a few.

    Gary, the one that made 607 rwhp is my 1990 Callaway Twin Turbo Aerobody. It also made 735 rwtq. The 1192 rwhp car is my 1967 Sting Ray. These runs are all made with full exhaust connected. Both cars are street cars. The '67 Sting Ray's 1192 rwhp is with nitrous. Without nitrous the car made 714 rwhp. I have made over 200 naturally aspirated runs and 32 nitrous runs on the '67.

    Steve
     
  11. GaryReed

    GaryReed F1 Rookie

    Feb 9, 2002
    3,093
    Seattle
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    Gary
    Steve,

    Those sound like a couple of extremely FAST cars!

    I'm amazed that you can get over 700+ rwhp without a supercharger or turbo on your Sting Ray. What sort of engine are you running?
     
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  13. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    7,940
    If the dyno can be interfaced to the engine ECU, you can inject random precisely timed misfires and measure the power loss of each cylinder.

    Take a car, any car, strap it on a dyno, any typical chassis dyno. arrange that the car is adequately ventilated so that the cooling and other systems are not limiting performance/longevity. Fill this car with gas and fully warm up the systems. Then start making pulls, do a couple of hundred pulls basically as fast as you can accurately cycle the dyno. Take all the runs and make an average of the TQ and HP graphs. One would expect all the measurements of that one car during that small period of time to be within +/- 3% of the average, one would expect 63% of the pulls to be within +/- 1.5% of the average. For a short run of 3 pulls, one can expect 1% levels of accuracy.
     
  14. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
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    Russ Turner
    Would love to see the graphs, especially if you have the A/F data.
    many thanks
    rt
     
  15. 4sfed4

    4sfed4 Karting

    Dec 22, 2003
    231
    A couple of hundred pulls in a row!?!!? Now that would be the dyno test or all dyno tests! I think most cars would blow up!
     
  16. markr

    markr Karting

    Sep 15, 2003
    196
    N. Virginia
    I was thinking the same thing.
     
  17. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    7,940
    A) thats what the "arrange that the car is adequately ventilated" phrase was to address.

    B) what is really different between a solid hour on the track and a couple of hundred pulls on a dyno?

    C) how would you measure the inherent error in a single dyno?
     
  18. atlantaman

    atlantaman Formula 3

    Mar 31, 2002
    1,726
    Roswell, Georgia
    Full Name:
    Charles
    A/F ratios:

    while trying to set up my 328 EFI, my mechanic is telling me to "keep it at stoke" but my dyno tuner is saying that it is too dangerous to be at 14+ above 5000rpm. He is setting me up for 14.4- 14.5 up to 5000 then grually down to 13:1 at 6500 and 12.5:1 at 7700.

    He cclaims that he has seen too many motors blow at hi rpm because there is no time to correct for slight changes and 2-3 seconds at 15+ can cook your goose.


    I would like to see any 308 and 328 dyno graphs available so I can build up a database for my programming. If you have some please let me know.

    Thanks
    Charles
     
  19. 4sfed4

    4sfed4 Karting

    Dec 22, 2003
    231
    Im not sure how an hour on the track would compare to a couple of hundred dyno runs! Id guess the dyno runs would be harder on the engine though as they typically start (at least when I do them) at 1500 rpm and whack right into the rev limiter. Those low rpm high load "lugging" pulls are brutal, especially on a boosted car like mine. Its also very very hard to duplicate the cooling effects of a car at speed on a dyno. 99.9999% of dynos dont have fans capable of such volumes and velocities. But, it really doesnt matter when you are only making a few runs at a time at least in my experience. I havent found that, for instance, my 1/4 mile trap speeds are way off what is expected after making the dyno runs.

    As far as inherent error, you are probably right from a statistical standpoint. But, for the purposes that most of us need a dyno, just merely using the same dyno for all runs after making changes, well know if we are going down the right path. Im sure my history might not be statistically relevant, but my car's first dyno run each time is usually made at the low boost setting and for the past 4-5 dyno visits, the first pull has been within 1-2 hp of the pulls from the times prior with the same setup. The curves lay right on top of each other and there is no way to tell them apart.
     
  20. 4sfed4

    4sfed4 Karting

    Dec 22, 2003
    231

    I know little about Ferrari engines, but engine are engines more or less. Thus, generally speaking, your tuner is correct. You never want to set up a car to run at stoichiometric at high rpm and WOT! Thats a recipe for diasaster and it will also generally produce less power than running the mix richer. The taper in A/F you mentioned above sounds pretty good.

    The other thing to watch is exhaust gas temperature (EGT) and its relationship to A/F ratio. If the A/F is where you want it and the EGT is higher than youd like, there is probably room for more timing advance (and more power of course).

    I assume this is a pump gas (93 octane) tune?
     
  21. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
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    Russ Turner
    When I was setting up the 3.2 webers on the dyno, I jetted to keep it right around 13 +/- 1 the entire pull. I did not notice a significant hp change between AFs from about 12 - 14 (a couple) on different runs. Just my experience. I have seen a 328 with FI dyno pull where the K-jet kept it right about at 14.2 the entire pull.
    Something interesting to me are AF's at idle, part throttle and tip in when dumping the throttle (a bit harder to control with carbs, but fun to tune). Are most people cruising at 14+ at part throttle? My dyno tech said that many newer engines even idle at 15 for emissions. Would love to hear anyone's experience if available.

    great thread, many thanks
    rt
     
  22. 4sfed4

    4sfed4 Karting

    Dec 22, 2003
    231
    I have noticed similar behavior before as well....sometimes there is very little change in power with relatively large A/F changes. When that is the case, I think it wise to keep it on the rich side!

    Was that car making modest power? 14.2 on pump gas with FI and any amount of power will generally be quite a bit on the lean side.

    EDIT - I took FI to mean forced induction rather than what I think you meant (fuel injection)! In any case, does the K-jet type control use O2 feedback?

    I will admit that I once ran my car (by mistake) to over 16:1 under quite a bit of boost once before, and it didnt blow up, but I think I dodged one there! And, power was certainly down.

    For chemcially perfect combustion, A/F should be 14.7:1. Most cars idle and cruise right at that point. The easy was to know if your engine is doing that is to monitor A/F voltage. The ECU will try to "hit" about 0.45V (if I recall) on average. But, it overshoots, then undershoots, then overshoots, etc, etc. If the O2 voltage is bouncing rapidly like that, then you are generally idling at something close to stoichiometric. (The narrow band O2 sensors are only highly accurate around stoichiometric.)
     
  23. 4sfed4

    4sfed4 Karting

    Dec 22, 2003
    231
    Yeah...post those wacko dyno runs steveb!
     
  24. atlantaman

    atlantaman Formula 3

    Mar 31, 2002
    1,726
    Roswell, Georgia
    Full Name:
    Charles
    exhaust gas temps is a bugger--hard to measure that one--I have a raytek heat gun that i use occasionally to check it out--usually about 725 deg f at the little "bungs" where the old air recirc probes used to be.. The gun has been really helpful too--had #2 up to about 780 so I removed the fuel rail and found a small clog in it.--danm good 150.00 investment.
     
  25. 4sfed4

    4sfed4 Karting

    Dec 22, 2003
    231
    I agree with you that EGT is hard to measure (if you dont want to drill yur manifold). If you dont have a problem with that, then its pretty easy :D
     
  26. SteveB

    SteveB Karting

    Oct 5, 2003
    62
    Puyallup, WA
    Full Name:
    Steve Barker
    #23 SteveB, Feb 25, 2004
    Last edited by a moderator: Sep 7, 2017
  27. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
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    Russ Turner
    As I remember, that 328 was pulling about 206 - 210 rwhp (~250+ flywheel).
    Yes, FI was for the stock Kjetronic. They added O2 control on the later US models - you can always tell as they have a frequency valve and the Euros do not.

    best
    rt
     
  28. 4sfed4

    4sfed4 Karting

    Dec 22, 2003
    231
    Yikes! Talk about a broad curve!

    What type of fuel did you use?
     

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