UPDATE Tuesday morning I will be taking her to a nearby dyno to get a baseline before the modifications and will report results. I will plan to take it back in the spring to dyno again and see what the intake and rocker change impact is.
I like the 323's for the highway but have been considering swapping them for a set of 364's. How much of a difference would that make?
View attachment buick.pdf Here is the dyno information. They said roughly probably like 320hp at crank. Said most chevy 350's end up at around 200 to wheels. They were having problems getting numbers and switched how they got them.
I have a TA C113 Cam. here is what the site says: VALVE LIFT STOCK 1.55 RATIO: IN: .472” EXH: .476” TA ROLLERS 1.60 RATIO: IN: .488” EXH: .493” DURATION AT .050 IN: 228 EXH: 247 ADVERTISED IN: 276 EXH: 295 LOBE CENTER: 113 POWER RANGE: 2500-6000
Just an update. Over the winter I worked on getting my car ready with the upgrades and the car was finally started in February. What an endeavor it was and at one point I thought why did I do this all lol I would like to thank Gary Paine for coming out and checking my work and helping me get her buttoned up and running! I haven't spent a lot of time testing and have a few more things I want to do, but the seat of the pants feels way better. I feel that the mid range and up RPM's have really changed and the car pulls much harder than before. I'm very pleased in the improvement. I plan on going back to the dyno and get real numbers to compare to the previous one after dialing things in. Just going to have to see if I will leave this carb on or try to get the 800cfm working on her. It gave us problems and we had to throw the 750cfm back on but I did change out the secondary rods to give her a little more fuel.
Hopefully you fixed something to get the engine to make power at a higher rpm. Something was wrong with that engine according to those dyno numbers. Peak torque came around 3600 rpm and max HP was at 4300. Those numbers don't jive. That dyno sheet is tough to make out but ultimately the peak HP number comes in way too low. I would think that the TQ to HP peaks should be closer to 1500 rpm apart. That cam in a BBB would make peak power around 5300 rpm and on a 350 it should be over that by a few hundred rpm even with mildly worked heads and especially heavily worked heads. Even a stock 350 makes peak HP at 4500 rpm and that C113 is 30*+ at .050" bigger than stock. I can't really say I'm a fan of the C113 once you put a set of headers on it. Even though it may not be optimum it definitely will make peak power way above 4600 rpm when everything is right. Going back to the dyno sheet you can see how the power dips down after 4600 rpm and then looks like it is trying to go up again. I would think when the dyno guy looked at it he should have said that just ain't right. Of course he's thinking it is only a "Buick" engine. I have to wonder if maybe you had too much lifter preload. I always run the minimal preload to get maximum rpm potential and put up with a little more valvetrain noise. If Gary helped set up the roller rockers maybe that is what he did. I may also look into a better ignition box if that doesn't fix your problem. I believe the TQ number is good but I'd say a little low on the rpm side. Maybe a few hundred rpm but not much and that is just a guess and I may be completely off. Without a doubt the HP number should be at least 25 HP more(minimum) but at a rpm closer to 5500 or more. Because of the relatively large cam in a "small" 350 the HP number should be approaching the TQ number. With your setup you should shift at 5500 rpm minimum and the car should be pulling hard(even with the stock intake) and maybe even 6000 especially with the SP3. Your engine should work well with the SP3 intake but for better ET's better gears will be necessary. YOU have to decide if the tradeoff in highway rpm is worth the better acceleration of 3.64 gears. How many times do you actually drive long distances on the highway and how important is a low ET? It is up to you. I know I drove thousands of miles with 3.42's behind a 455 and it didn't bother me at all and that would include multiple trips to the GS Nats which is a 700 mile trip one way. But then I think a low ET is important, gas mileage not so much. Your numbers on the dyno should be fairly close to reality because of the stickshift so you don't have as much power loss through the drivetrain as an automatic would with varying stall speeds. From what I've heard changing the gears in the back will cause the dyno numbers to suffer some amount also. What kind of fan do you run? If it is a thermal clutch fan that can cause a greater HP loss as the engine heats up on the dyno. For consistency when I run my car on the chassis dyno I install a non-thermal clutch fan. This will keep the HP drain consistent from run to run. A thermal clutch fan can, when cool use slightly less power, and when hot use substantially more hp. My motto is non-thermal clutch fan or electric fans for dyno consistency. Also were your numbers corrected or raw? Corrected is better because you can compare numbers on different weather days. Hopefully they can do better next time with a more useable dyno sheet. I'd look into borrowing a 750 DP Holley to try on that intake while I was on the dyno just to confirm your own carb is OK. You should be getting that car ready to go so you can make it over to Columbus for the Dick Miller BOC race in July. With the heat ET's won't be the best but at least there will be Buick guys around to help you out with the car.
Chassis dyno #'s are fairly useless for engine power #'s. They can be a great tuning aid to judge changes made right then and there. They show huge deviations from tires or chassis. Inertia or loaded dyno? Inertia types don't favor engines with heavy bobweight. Brake types use constant load vs. engine dynos often use controlled sweep rates or step testing. Slicks or possible deviations in tire radius or traction? Chassis moving around at all? Any torque absorbed loading suspension components or deflecting parts? Would that stay constant through the pull? One thing missing would be when compared to popular engine dynos... there would be a correction for inertia (because of the load brake mounting method and how the torque reading is taken). It would require a huge database to factor in the mass of the entire accelerated driveline. Meaning, you would never be able to have an apples to apples sampling. Every engine family/drivetrain combination would correct differently. If the engine seems to pull smoothly then I would chalk up the #'s from the dyno as "inaccurate". Is it possible that the peak torque shown wasn't quite at peak torque yet and that the dyno was only reflecting the the max amount of torque transferred to it? (Losses suggested above). I do not subscribe to the line of thinking that peak torque is cam controlled, unless severely starved. (Therefore I support the suspicions in the post above not adding up quite right with the printout) What I mean by that is that you can expect a similarly built 350 to show a similar torque curve, with tuning rounding things out. Peak torque should be at a similar rpm . I would guess the dyno's peak hp was reflecting the downside of losses or error and that your real torque curve goes a bit higher. Doh! Just re read that they were having problems with their torque readings!
Hi Guys, I will start out by saying that I just wanted to get a baseline on a dyno for the car before changing anything. The changes I made I wanted to do when i had the motor done but the SP3 wasn't available and roller rockers were not in stock. I have never taken her to the dragstrip either. The dyno guy did have problems getting a reading with my pointless ignition system I have. When on the dyno he took it easy on the motor as well. The car should have no problem getting up to 5,500 rpms and I have taken her up there numerous times shifting. My real goal is to improve the performance of her but keep her looking stock appearing. The lastest upgrades were a high volume water pump, TA 1.6 roller rockers, SP3 intake and a 800 cfm qjet. The qjet just wasn't running right so we put my 750cfm back on. Also I changed the secondary metering rods in the Qjet as well. When I take her back to the dyno I plan on getting a printout similiar rpm and then one more in the 5500 rpm range as well. I will also consider changing the gears out at some point down the road.
