Thought you guys might enjoy checking out my two Dynojet runs yesterday. The first one is with open exhaust with my cutouts uncorked and the second one is with exhaust. Believe it or not, RWHP was just one HP less, 278 open, 277 closed. The operators told me about 17% correction for a manual trans car so about 325 HP at the flywheel. Not bad for a street car with a mild 262 cam I thought! Was a lot of fun (and it didn’t blow up!). I had them take it to 5750 RPM, the MSD 6AL was rev limiting around 5200 with my Dial-A-Rev-Limit ™, I had forgotten where I had initially set it.
Very cool Bob. I read in the other Carlisle thread that you were delaying you trip due to weather. Nothing wrong with keeping the under carriage clean. After those watching those videos nobody can say your vert wasn’t built to drive.
Steven
First, just wanted to mention/reiterate that the wiggles up high on the graph is the MSD 6AL rev limiter kicking in.
Now, to answer your question Mark. The engine is a 351C .030" over with L2370-30 Forged Speed Pro pistons. SPS rod bolts (the hot fasteners back in the day before ARP), .010"R/.010"M 4MA crank. Australian 302C small port closed chamber heads with stock size Ferrea 5000 series intake valve, 4V size Ferrea 5000 series exhaust valves, .5" bronze valve guides (not liners), Boss screwed in studs and guide plates, Procomp roller rockers. Custom length pushrods to get good valve head contact pattern. Custom Cometics head gaskets to lower the compression ratio to a true 10:1 measured using a Katech Whistler. Really too much compression for today’s pump premium with Ethanol and iron heads. Comp Cams XE262 cam (mild, for the street), largest cam recommended to 3.25 gears, an RV sort of grind which BTW causes my dynamic compression ratio to be too high for pump fuel - I am attempting to deal with that with fuel via carburetion. Edelbrock Air Gap manifold, Quick Fuel Technology SS-750-AN carburetor (an enhanced Holley design with annular boosters). Cragar 4V headers with flanges welded up to 2V port size, custom homemade 2-1/4" 409 SS exhaust with Magnaflow SS mufflers. Duraspark triggered MSD 6AL with Dial-A-Rev-Limit ™ remote rev limit control. Wide ratio toploader 4 speed, 3.25 gears.
Think that about covers it (and maybe more than you wanted to know!). Thanks for the interest and great to see you Mark, the weather made it an unusually short trip for me. I would have liked to wander the swap meet and talk to more people. The dyno was a bit nerve-wracking (would it blow up? - I’m 3 hours from home!) and the block-offs were hard to get off because I used metric SS washers, need to drill them out a bit. In the end, it was a rush though and I got some more data to continue to refine the tune and/or decide what I should change in the build to get it to work even better.
Second was with exhaust (same order as the video’s). Yes, the AFR looks pretty fat with exhaust (which is the 95% usage configuration). I can always jet down (it’s a QFT SS-750-AN I just installed recently). I have been struggling with lean AFR conditions causing detonation. I have (initially) succeeded in better controlling this by going from a 650 to a 750, I might be able to lean things out a bit but not going to stick with that if my detonation returns. I unwittingly built a combination with too high a dynamic compression ratio and that makes for detonation. I am trying to avoid the “me too” cam which shifts the power up higher - where you don’t want it for the street - but the overlap would lower DCR. And, I would get “the sound”, but I’d rather have an engine properly built for the intended purpose.
Have a call into the dynojet company to see how the exhaust probe was placed in the open exhaust run. If it was in the tailpipe then that data is bogus (and I may actually be running “fat” regardless).
Wasn’t it Bill who mentioned in Brian’s thread about switchable open exhaust that the timing needs to be tweaked for open exhaust? If I’m remembering that right, that leaves me wondering if your car is dialed in for normal exhaust and thus is missing out on some potential boost from running open?
I’d love to get my cougar on a dyno but have a feeling I wouldn’t be blown away by the results, stock 302 and all. So great that you took advantage of the chance to get Isabel up there. Fwiw I think she sounds great with the exhaust not open.
You need to install a couple of wide band sensors to get good data. I wouldn’t do anything until then. IF it is fat, then I would look to the power valve first based on what I am seeing.
Got one, a AEM gauge with Bosch Wideband O2 sensor. Don’t have data logging hooked up (although it is capable - serial port IIRC), maybe I should look into it. But then I’d need tach logging too, right?
Have since relocated wideband sensor from the crossover to the PS side main pipe, need good regular flow rather than crossover pulses for accurate, responsive readings.
