Help? How Much Hp?

[RSMAN]

I'm finishing a new motor,first time at this level.I would like to know how much horsepower do I have a chance to make, at what RPM @ shift point? MY COMBO: DART BLOCK SBF 427ci. 4.125 bore, 4.0in STROKE, 4340 SCAT STEEL RODS AND CRANK, 950hp CARB, SUPERVICTOR INTAKE(ported), VICTOR HEADS flow 355in @700lift \ 282ex @700 lift ported by (TOTAL ENGINE AIRFLOW). CAMMOTION CAM DUR. @.50 280in\293ex. LIFT 736in\718ex. 1.7 ROCKER, LOBE SEP. 113, CENTERLINE 109. ROSS Dome PISTONS 14:5 COM. MOTOR WILL BE IN A 3100lbs CAR WITH A C-4, 3:73 gear. WHAT ET & MPH can I look forward to. THANKS GUYS

[Sammy]

I would say you are looking at around 750 hp. Based on a flow rate of 360 cfm, you are in theory looking at a maxumium horsepower level of 778 with 12.5:1 comp. @ 8500 rpm. However you are running 14:1 and your cam should make peak power at 7650 rpm. I developed a spreadsheet that allows me to calculate cranking compression based on low lift flow rates and cam specs. I ran your cam specs and came up with a cranking compression of around 190 psi. You should try to target a cranking compression of around 235 psi. The only way you can achieve that with this cam is to run 16:1 compression. At this compression level it would put you at around 820 hp. I would check your cranking compression after your rings are seated and see where you are at. (Make sure you do this with the carb off from the manifold.) If you are sick over the thought of replacing your flat top pistons with domes you could run a smaller cam. Your E.T. would definately improve. The Lobe Sepration Angle of your cam (113) would be correct for 16:1. However, at 14:1 you should target an LSA of 111. Which might be hard to come by. You are probably going to find a 110 or 112 LSA easier to come by. I would recomend a 112 with an advertised duration of 304/314 or dur. @ .050 of 270/280. Just as before install this cam 4 degress advanced. This cam would make peak power at 7250 rpm. It would also be about .2 tenths quicker than the cam you currently have. It will feel a TON faster by seat of the pants. Another tip involving your valve lift: Your engine would like alot more lift than your giving it regardless of the cam you choose. The way to achieve that is with a higher ratio rocker. This will in my experience greatly reduce the valve spring life. But the engine will love it. It all depends on how radical you want to get. I run a 1.9:1 on my intakes. I get about 10 passes before the springs are shot. In any event your engine would like about .900" of lift on the intake side and around .750" on the exhaust side. One finaly word of advice: Make sure you ceramic coat the tops of your pistons and coat the skirts w/ moly at these elevated compression levels. By the way you didn't say what gears and tire size you are running. I need to know that to calulate your E.T. and mph.

[RSMAN]

THANKS FOR THE INFO GUYS! I HAVE A COUPLE OF QUESTIONS. I am not running ROLLER CAM BEARINGS so how much lift can I run with standard bearings? It's a trade off because a can't afford to change valve springs every 10-15 passes. I'll be sending my intake in next week to be fully ported by TEA. CARB to go to PRO SYSTEMS. I'm on a tight budget so I'll have to use my C4 tranny until the late fall. I have 3:73 gears in the car now(from my 408ci NOS motor of last year) and a set of 4;30 GEAR. I do not have a CLUE on what gear (ANY GEAR) to use. Maybe you can help me out here, gear w\C4 & powerglide? MY CAR WAS 3060lbs but I've heard I'll be picking up wieght with the DART BLOCK. I use MT 28-10.5 slicks, stock suspendion w\anti-roll bar. BEST 60 foot 1.37 with a 3;73 gear on NOS last year w\c4 trans,only went 9.40s. I have not got rocker shaft yet so not stuck with 1.6 rocker. AGAIN GUYS THANKS FOR YOUR HELP, I HAVE NOBODY LOCAL TO TURN TO.

[windsor396]

I think most the guys in Hot Street run upwards of 5.00 - 5.29 gears or better. Just depends on how high your motor can spin and where it makes power.

[RSMAN]

THANKS FOR THE INFO KEN YOU HAVE BEEN VERRRRRRY HELPFUL! YOUR HELP IS APPRECITATED MORE THAN YOU'LL EVER KNOW, GOOD LUCK NEXT RACING SEASON!

[Sammy]

It's good to hear your getting the intake ported; that is money well spent considering the awesome set of heads you have. But before you go out and spend more money you need to get this thing on the dyno or better yet make a few passes and start getting things sorted out. At this point I think your money would be better spent on a set of gears as opposed to rocker arms and valves. But BushRacing is totally right about the titanium valves. H/S rules mandate a weight of 3200 pounds for your C.I.D. I ran your engine at weight of 3200 lb. on my spreadsheet. This is based off from the work that several engineers from Mopar did in the late sixties that allow you to predict E.T. and hp from trap speed. We know your cam is going to make peak power at 7650 and you want to go through the traps 200 rpm higher than peak. We also know (expect) your engine to make around 750 hp. If you use a 4:56 gear you will go through the traps at 7850 and it will require 730 hp. If you use a 4:30 gear and you go throught the traps at 7850 it would require 871 hp. Obviously the 4:56 gears would be a better choice. Now for your E.T. It is possible believe it or not to run as fast as a 9.15@ 143mph. However it is not likely. In this case mainly because I feel your cam is too big which is going to cost you torque and your chasis is not theoretically perfect. I would say realistically your looking at the 9.50-9.60 range at around 137 mph. The other option is to use the smaller cam I recomended below with the 4:30 gears. I think the smaller cam would lock you in for a very competitve 9.20-9.30 E.T. in his class and there would be less wear and tear on the valve train. $250.00 for a cam versus $189.00 for a set of gears.
The bottom line is: Theory is great but testing is worth more. You can spend all kinds of money (as I'm sure your aware) on everyone's advice. If it turns out your cranking compression is on the money with the cam you currently have and the 4:30 gears are putting you through the traps at 200 rpm higher than peak h.p. than great: That means you are going to win races. If not than you have this information to fall back on and you will have a better idea of the changes you need to make.

[windsor396]

I disagree with the 200 over peak horsepower going through the traps. I tried that and it didn't work for me at all! These windsors to spin in order to stay in the power band. They don't make enough low-end torque to recover from shifts etc.

My example:
3230lbs car with my 402ci in it peaked at 7800 RPMS. My best run to date was shifted 1-2 at 9500 and 2-3 at 9600. When we tried to shift the car at 8000-8500 we would slow down over a full tenth.

Just me experience in Hot Street and my own .02

[Sammy]

Windsor396-
What is your compression ratio and L.S.A.of the cam your currently running? I find that extremly interesting (and odd) that you are shifting that far past your peak. Don't you? What is your cranking compression? Ultimately it comes down to the average power you are making in the rpm range of operation as I'm sure your well aware. With your engine the power band seems to peak and hang on forever.
Just to clear the air a bit here: I am not protraying to have a faster car than you or more experience. I run a 393 with Vic.Jr. heads and a Super Victor Intake. It has 12.5:1 comp and a 256/264 dur. @ .050 flat tappet cam. I know that is a small cam compared to you. But I intend to run a 9.60-9.80 this summer with it. Last year I was going through the traps @ 128 mph with the same cam and 11.5:1 comp. ratio. Have I tried a bigger cam? Yes. Did I go faster? No. Not only did my E.T.'s not improve but I found the car to be allot more difficult to launch and shift such that my E.T.'s were consistant. In fact most of the time my car was slower. (And that cam only had four degrees more intake and exhaust duration @ .050!!) Where I am comming from: I would like to pass along what I have learned to see if it helps you guys go faster.
I will fully admit that from your perspective my SCAT cast steel crank and my Hyperutetic pistons and my 28 spline Moser axels w/ a TKO trans are all junk. Ha Ha But I really have a good time and I totally enjoy learning more about naturally aspirated h.p. The spreadsheet I developed relies upon the laws of thermodynamics. (adiabatic compression) It has allowed me to predict cam specs for engines in the 302-427 c.i.d. range. I got the recomended L.S.A. and lift info. from a doctor of automotive engineering out in Arizona. (I think his name is Kenny) It is absolutly fasinating stuff. Who knows where cam science could take H.S. in the future. Anyways from a cylinder head perspective it is the low lift figures that matter in specing out a cam. This becomes critical when both valves are open at the same time (overlap). So your major variables are: Comp. Ratio, C.I.D. and low lift flow numbers. Flow numbers above .100" are significant in terms of the power your engine can make. Duration determines the rpm range of the cam. As you increase it, you must also increase your compression ratio and L.S.A accordingly.

[90GT398]

I am no Hot Street racer by any stretch,but I have seen a few dyno pulls and done testing with my 90 LX and I always thought the general rule of thumb was to shift 800-1500rpm above peak hp?

When we all had stock Mustangs years ago they made peak power at 4400-4800rpm and I know for a fact I never shifted mine at 4600-5000rpm. I always threw the 1-2 shift at 5400-5700rpm.

I know this does not help with the question about how much power it takes to run with the Hot Street cars, but I thought it would help with the discussion about peak hp.

Maybe it did, and maybe it didn't:confused:

[Sammy]

Shift rpm, and the rpm you go through the traps at, are two totally different things. For instance: You could have 3.27 gears and still shift at 5400-5700 rpm. However when your stuck in fourth gear at the end of the track you may only go through the traps at lets say 4000 rpm. Conversly you could have 4.10 gears and still shift at 5400-5700 but you might go throught the traps at lets say 5000 rpm. The 4:10's would be faster (providing there's traction) because you are staying in the range where the cam makes it's best power. I think 396windsor was trying to say that he shifts AND goes through the traps at 9500 rpm. In his case the engine makes it's peak power at 7800 rpm and then holds on to that peak, with minimal loss, for several hundred rpm.

[windsor396]

Truthfully I have no idea how to answer half those questions :) I'm just a computer guy... Truthfully I'm sure you have 100 times the experience that I have! Up until this year I raced 400+hp street legal motorcycles.

I was just adding my .02 worth of experience from driving my car all last season. Check out this link, it contains one of my Racepack graphs from Atco:


http://www.nmraracing.com/forums/showthread.php?s=&threadid=2755

[RSMAN]

Anybody else have an horsepower estimate on my combo?

[Outlaw351]

Somwhere around 750hp, with a ET range of 9.55-9.70 and 137-140mph.

[383natural]

ken i heard your car made 840 hp at glidden's shop is that true? how much did your livernois motor make? just curious what the difference is....

[Jubi351]

Hey Sammy, I emailed you a question. Be sure to check your mail.

[boywonder351]

Sammy/Guys,

Interested in your input regarding my 393 combo to be complete within the next few weeks by Kotzur Engines:

9.5" Sportsman Block, 3.850 stroke, 4.040 bore, Scat cast 4340 crank, Eagle 4340 H-beam rods 5.956, Ross 16:1 gas ported pistons, Victor 7721 heads 370@0.700/267@0.700 (ported by West Coast Cylinder Heads) with 1.70 T&D shaft mounts, Cam Motion solid roller grind 262/270, 0.700/0.700 @ 0.050" w/ 110 Lobe Center, 46 degrees overlap, 25,57,69,21 (IVO,IVC,EVO,EVC valve events) Super Victor intake w/ plenum floor cleaned & gasket matched to Felpro 1262R (by Kotzur Racing heads). Pistons out of the deck .005", Holley 930cfm, Kooks 1-3/4 x 1-7/8 x 3-1/2 step headers, C4 trans, 4.10 gears, 31 spline, only suspension mods are SSM lift bars, subframes, lakewood 90/10, 50/50, 8 pt cage. Cone 5400 rpm stall (approx)

Car is approx. 3200 lbs, w/28x10.5-15 MT ET drags.

Calculated compression is 16.02:1 from a program I've developed in excel. HP & TQ numbers are 710@7500 & 593@5500 through the mufflers (without advancing the cam) from an outdated Dyno2000 program.

Unfortunately, I do not have a program to derive cranking compression. With these figures, how accurate do you think the HP & TQ numbers are and what would you expect ET & MPH to fall at?

I've also heard that it is desirable to have your peak volumetric efficiency to fall approx. 200 rpm past the shift point???

If you need low lift flow numbers, I can email you my flow data.

Thanks,
Brian

[Sammy]

Brian-
Your cranking compression will be around 316 psi with that cam. When the motor is finished and you have seated the rings check it for yourself and see how close I am. :) Bottom line: That is way to much compresion for that size cam. I think you will find that your engine will make it's best power at around 20 degrees total ignition advance because of that. I also think you may have problems with detonation. If you want to get the exact perfect cam for your combo e-mail me your flow nubers from .100 on up.

[sam sso2077]

I too use T.E.A.
I have a set of Brodix neal 202 heads and Edelbrock Victor"glidden" intake. My bore and stroke is very similar to yours.
When I had aset of raised runner TFS "R" heads(very modified)266cc port volume,flowed 406 int. & 294exh. @ .800" w/ 52* seats. Chamber was 49 cc which mad 14.5 with flattops. My first cam was a Ultradyne 278/287 @ .050 .776/.755 lift w/ 1.7 & 1.65 rockers on a 110L/S installed on a 106 centerline. It made 782hp @ 7300-7400 rpm and 620lb/ft of torque @ 5300rpm. With nothing more than a cam change to a Cammotion cam, keep in mind this is a nitrous cam, Same rockers .828/.795 lift, 286/302 @ .050 on a 115 L/S installed on 111. It made 810hp @ 7500rpm and 632 lb/ft of torque @ 5700rpm.
This engine in my 2900lb outlaw car with a "tight ass" nitrous convertor and only 3.89 gears it ran 9.44@ 148 mph.
Now with a danny bee belt drive and Brodix neal head, Ive been 9.27 @ 152.4 with even tighter convertor and same 3.89 gear.

For your application, you definently need the intake ported. Also, T.E.A. now has a 400cfm port for the Victor head. You should also talk to brian about changing the valve job in the future to a 52* or 55* seat set-up. You really need titatium valves(at least on the intakes, they're the heaviest). You could probably have the heads milled to raise compression, it's always better to make the compression with a flattop & smaller chamber than a dome & bigger chamber. Next time the engine is apart, put aluminum rods in it, have the pistons dry film/thermal coated. You can even have the crank & rods coated with an oil shed coating.
You rewally need a glide in the car OR a TURBO 400 with a 2.10 first gear set( a lot of hot street runs this set-up). As for gear, I would say a 4.56-5.13 depending on you shift point, convertor, tire size, and weight.
If I were building a hot street motor for the rules of NMRA and considering the weight for the cu/in. you are I would do a 4.125-4.155 bore and 3.700-3.750 stroke to stay in the 400" limit and can still make over 800hp.
Feel free to e-mail me with any questions. I build my own engines

[sam sso2077]

Everthing you listed looked to be in order for 650-725hp.
In my humble opinion your headers are way to small. You need at least a1 7/8" 2" step header if not a 2"- 2 1/8" step header if you are spraying it. The 3 1/2" collector sound good.

[RSMAN]

SAM SSO2077, Sam i had talk to you by phone about buying that Ultadyne cam a few months ago but order one from Cammotion. My motor is order and will be finished in 2 weeks. Final compression is 14.5, cam is 280\293 Dur. @.50. this is a nitrous motor but I will run H/S. Please give me your input on HP & anything else since I know your a Nitrous man. My car is 3100lbs, 3:73 gear, C-4 with 250-300HP of NOS. What kind of ET & MPR I can look forward to when properly tuned on motor & NOS? I want to run in the 150+MPR range on Gas. People are telling me the motor will be lazy(will not run)on motor.

[snakehorse1]

Yea RSMAN - I'm in the same boat, you can't have your cake and eat it too. You either have to set the motor & car up to run NOS or on Motor - one is alway compromised.

I would love to go play with the boys in HotSreet however I realize that with my current set-up I would not be that competitive so rather than driving around the US only to go out first round I choose to spray the hell out of it and have fun locally. I took my 382 that was good for 9.70's on motor and set it up for NOS which took that number down to 10.30's - 1.65 60ft:(

But now when the bottle gets turned look out:D

My opinion is if you plan on class racing - set it up for the class but if you just want to go out and have fun - set it up for what "you" want to do.

Remember - Have Fun!!!

[sam sso2077]

You need a lower gear for motor passes and a motor convertor! You need to ditch the C-4 and put a glige in the car!!! With out knowing the rest of your combo it would be hard to say. But it should be easy to go 150mph on 200hp, hell it should go near 160mph if not over on 300hp.

[RSMAN]

If I can run that kind of MPR you will see one big smile on my face! Mission Accomplished! Thanks for the input. I went with TEA for portwork because every car I know or saw with Brain's heads(REN to 408's) have made good horsepower,maybe I can too. Special Thanks & Support to the TROOPS IN IRAQ. I Was in IRAQ IN 1991 in Desert Storm with 3 Armour Division but they would'nt let us go to Baghdad, BUT KNOW ONE COULD STOP YOU! JOB WELL DONE!

[RSMAN]

Finially got my motor in and fired up. Might take it to the Chaisis Dyno before going to the track in two weeks.Can i go 9's my fingers are cross. Thanks to all who has replied! Ken Compton, nice meeting you at the FFW Richmond race.One real nice race car.

[Aronson3510]

I know that when you list out a bunch of parts and then speculate what that combination is capable of doing, it is like trying to guess how many beans are in a jar. Until you dyno the engine, and know every variable on the car, you are shooting blind. As you know in Hot Street, if you are running that many inches then you are packing a lot of wieght! Also, that means that 750 hp, would be lacking between 50-70 hp of being competitive. However, the big inch cars are the ones that are consistant. I am sure that nobody can just walk into hot street and clean house, so your chances are as good as anyones.

Good Luck!

HS3510

[RSMAN]

I just like to race/compete,tired of bracket racing. I'd rather get beat by a faster car than a 15sec station wagon w/open headers. I know I didn't have a chance in hell to win a race. I don't have the money to build a REAL MOTOR,but can I get an "A" for effort.:p thanks for the reply. Gonna run 1/8 this weekend 7/19, car's first pass of the year. I'm Scared to post result after seeing the S/B boys(with many H/S in attendance)run at Richmond FFW, but locally I'll be The Man with a 9sec all-motor car. Thanks.