Do you have more info on this? What are the heads flowing? What is the cam? ________ Suzuki dl650 v-strom
On the power note and cubic inches, I feel it depends on where you want the power and what you plan to run with respect to the power you have. Alot of power is only good if you have rpm to use it. A properly setup combination 450 cu in can make just as much hp as a larger motor just at a higher rpm. I feel you need to judge your weight, airflow capacity and rpm needed to get the job done and build the combination to match. I'm going "small" at 470 since more cubes will just kill me and my rpm with a power adder. I feel anything with over a 4" stroke is a waste of money and it just more abuse on parts when looking at a race motor. The Large bore is definitely the way to go. It will broaden the power band and make more power over the same cubes on a stroker setup. There are alot of Buick guys flying with strokers with over 500+ cubes but if you can add bore that is by far the best way to go for torque and HP on a race motor. You can build a low rpm torque monster if you want but you need to look at the rpm range your actually running in going down the track and see what that stroker is really giving you. Your breathing capacity is going to be your biggest factor. Unless you spend the money to flow the air is just wasted money on the cubes if you ask me. With under 400cfm, I can't see the benefit of over 500 cubes unless your racing a 4000 lb car and can't get the trap speed to use the rpm. If you build a motor that makes peak HP at 6100-6300 but need to turn 7000+ plus, you built the wrong combination for your car. You can't just take gear away and expect it to go faster. AND if you add duration to the cam to make more rpm with limited airflow but it causes a drop in peak HP, how much have you really gained???? It takes both airflow and the properly matched cam for the size of the engine to turn rpm and make power. YOu go bigger on the cam then what the heads flow for your cubic inches then it going to cost you Hp for the extra RPM. Buick heads, even some of the few high flowing 400+ cfm heads are under 300cc and lack the volume to feed a large 550+ cu in motor at 7000rpm range. I think the only people that have heads over 300 cc's on the intake port would be Mike and Scotty. Airflow is great but it works in pulses. There needs to be enough volume with the air to feed the cubes. If someone wants to spend the time to throw down the math that would be great. I'm not against big motors but there's alot more to it than just making it big to go fast. The best thing about big motors is there alot more forgiving on the combination but limit total potential. Torque is great and gets things moving but it only lasts for 60ft. :blast:
Rick, you're right . The thing I am worried about with the new block is running out of cylinder head. A 540 inch motor flowing 300 on the intake side is strong but not as strong as it could be. The cool thing is buick can now go big but I know my race car went faster when we put more gear in it(more rpm) --- the thing now sings at the finish line (9500). Torque is a good thing but as Rick said , if your torque peak is way downstairs, what good is that doing for you at the race track. If your torque peak is at 45-5500 and your trying to shift at 7000 the car is 'running down hill' at the gear change. We figured this out after looking at g meter readings from the data acquisition. The acceleration was dropping off. Now our splits between gears is like 5-700 rpm depending on the gear. My combination is kind of apples and oranges but the concept is the same. At 459 inches my heads flow well of 500 cfm in the intake. That is extreme but if I had a 540 inch bracket motor (and I did) I had 420-430 cfm brodix cncs and the car ran 8 te ens at 2700 lbs on motor. That was a steel rod motor than was a 250 pass a year motor. Thats where I would want to be if I were building one of these from scratch. When you start lowering your et you start raising your maintenace ... Cant wait to see these this get built ! George
This is correct. In pro stock the deck height is less than 9.315. When you think about it, the engine is a small block with a big bore and big chief heads.John, this is one reason why i went to a small block. When you have a big block it takes more HP to get the rotating assembly going. The pistons are bigger and heavier, rods are longer, cranks are also heavier, not to mention the weight difference in engine size alone. The weight difference between my BBO and my SBO is 205 LBS. Loss weight is ET! My bob weight is 1435 grams, the crank weighs 51 lbs and i can still knock off another 6 lbs. Dont get me wrong, i`m impressed with the HP figures i see from people on this board. BBB seam to make easy HP. Happy holidays John.
This is to help us little people understand big talk With the current heads and flow numbers one is limited to X number of horses. Using a rough formula of cfm x .257 x #of cylinders =hp. This would look something like 400cfm x .257 x 8 = 822hp, this again is rough math based of a VE of 100%. This is regardless of CI this is the ball park number. All other things aside for now, one needs to look at there overall desires and set-up accordingly. If your looking for the fastest possible ET's as is Rick C. and some of the other heavy hitters than they need as much usable RPM as possible, so they want their 822 hp(All other things aside for now)at 8000rpm. This will give them the most mph with the same gear. example I have a big inch engine that peaks at 6500 rpm with a 30" tire and 4.10 gears, so this is my max mph not counting conventer slip. tire dia 15/constant168xrpm6500/4.10=mph141.55 Now rick has a big bore,short stroke set-up that gives him the ability to turn his engine to 8000, but all else is the same. 15/168x8000/4.10=174.2mph or they can run more gear thus getting more multiplication tq/hp. example. On my big inch motor I make a wicked 800ftlb at 5000 rpms, and Ricks combo he only makes 655 at 6800. But I want to beat Rick in the 1/4 and he is running 8.0's at 174. For me to get that kind of MPH I need to get rid of some gear. In order for me to run 174mph I need to drop down to a 3.33 rear gear with my rpm limit of 6500. So here is the how things look after the gear changes, with both of us using a t400 1:1 3rd gear. My awsome 800ftlb x my 3.33 rear gear =2664ftlb to the ground, while Rick's weak 655 x 4.10 = 2685ftlb. So as you can see I lost all of my tq advantage and then some. This is again rough math. So now you take in account for that Rick's set-up will raise the VE which will make more power. Going to a larger bore shorter stroke could raise your VE to as high as 125% or so which would put you at 1000hp range. While my set-up may only go 110% on the VE. Rick's engine will turn-up quicker combined with a deeper gears would make his fream ride fly. While my long stroke, heavy rotating mass and tall gears will make it rev much slower. Now Rick's engine will require better guts ie valve springs, rods and such and his parts will require replacing at a much higher rate. I read in some of the above post that the big inch motors and long strokes are hard on parts. That is not entirely true, if you look at all of the big engine builders, RM, Bill Mitch and such one will see that they sell big inch long stroke motors that make over 1000hp and peak rpms under 7500 with warranties some of the warranties as long as 12 months. But their high RPM motors that turn above 8000rpm have none. It is no secret that RPM kills and engine. That is why you can buy a 600ftlb diesel with a 100,000 mile warranty, but can get one with a 500ftlb small block chevy. But if you want to go really fast you need to TURN IT UP. So as I said up top you need to look at your desires, goas and then build your set-up. Trust me if one size fit all then car makers would only have one engine. I just got done reading an test that pitted the Ford GT against a LAM and Ferrari. The ford did great with it's 3.55 bore and 4.13 stroke.
Alan, I think your combo will work great. It seems that the turbo guys that are going fast run smaller stuff and turn up the rpm. If I were you I would call somebody like Duttweiller or another turbo engine builder for a cam profile. He's done enough Buick V6 stuff he can give you a pretty good clue. Seems wierd to be able to turn big rpm on a BBB doesnt it? Which heads are you running? George
maintenance The really big stuff (IHRA pro stock ) at 800 plus inches is still getting cycled at 25 to 50 runs and they shift them at 7500. The light stuff is still too heavy to really spin hard. they run a gear from 4.00 the 4.30 at the most while NHRA runs 5.0 to 5.29. If you build a 1000 hp motor and shift it at 6500 making 800 hp it will last no question.The bottom line is you are not going as fast as you could if you turned up the wick. have a good holiday George
Allen, it goes back to what are you looking for, and will that change in the near future. If you look back a couple of years ago Popular Hot rodding did a article on a big inch pontiac with twin turbo's. I want to say that the engine was in the 540" range. It made like 1700hp race tuned and then they took some boost out so they could run pump gas and the made 1500+hp and spent the day driving around in socal. G-lark has the right idea talk to the pro's on this type of a question and then post what they have to say so we are all smarter. I would say that I think you are on the right track. You do not need the inches when using power adders. The big inch engine are for N/A route for the most part balancing power and realibility. All this talk is about a new block where a low rpm engine is 7500 and below,7500 and above is just starting to turn it up. You will see a pretty straight cut line between the two mind sets. The rpm guys will be running under 8.50's n/a in a 2900lb car with many tear downs and then there will be the big inch guy's that will run 8.70-90 n/a getting a couple of years out of their set-ups. The inchers will never be able to compete with rpm gang. And no one in the BOP world will still be able to hang with the ford/mopar/chevy guys in a heads up class. By the way I'm back from the 3rd tour in old Afghanistan, glad to be able to post and hang out with you'all on a regular basis.... :blast:
The only thing I have for now is iron stage1 heads. :error: A good set of heads is on the short list, though. My first order of business is to get everything together and get it down the track, then upgrade as needed.
George you are on the money thanks for your input. Most of us here in buick world are just throwing ideas around until some engines get built and then the learning curve will start. It's good to hear from someone that has lived the life and share some real word data. There is a price to pay for that extra 1000rpm's. I have been trying to find the pro mod data vs pro stock has it compares to different directions speed junkes can take. But 25-30 run life cycle is better that 5-10 runs. Thanks again.
