Tomulrich

What do you think of these numbers? 436 small block, solid roller 260/270 dur @.050 .720 lift, 11.0:1 CR, weldtech/brodix raised runner heads, miniram.
I was hoping for 500 RWHP.......not real happy with the numbers I got.

Tomulrich

http://bowtye8.tzo.com/tom87/dyno436.jpg

Nathan Plemons

Well what did you get and how long did you spend tuning? Unless you've spent a lot of time and have the tune nailed down perfectly I would be very suprised if you got the potential out of the motor on the first dyno run.

Post the graphs if you can and maybe somebody can give you some pointers.

Ken Lanham

That sounds bad butt! I would think 500 rwhp would be quite possible with that combo. What is your current combo that you are so unhappy with? What are the dyno figures from that?

-Ken

Ken Lanham

Disregard that previous post. Your link wasn't up yet when I made that.
While the peak figures are not that impressive ("you said that") MAN does that thing have one heck of a broad powerband! That would be a killer road race motor. You would never need to shift!

danno85

:iagree: that is a very impressive torque curve!! :yesnod:

CorvetteZ51Racer

Do you happen to know what the flow capacity is of the MiniRam intake? Also, how big of a TB do you have?

Nathan Plemons

Sometimes a picture is worth a thousand words, so to beter get a feel for what's going on here is what the curves look like



I also noticed something that got my attention. The dyno sheet you had said third gear test, is your car an auto or a manual? If it's an auto you're probably fine but if it's a manual you really want to dyno in your 1:1 gear which is typically 4th gear. I've a 6-spd car give up 10 HP across the board on back to back runs by simply running in 3rd gear rather than 4th. Also if it is an auto that will cost you some power right there. Auto's just dyno less.

Secondly who did your heads? You said they were Brodix heads, were they further ported and polished or are they straight out of the box, what type of valve job do they have, etc? I ask because it looks like your torque curve really starts to fall off pretty fast after 5500 RPM's I had the same thing prior to having my cylinder heads ported. After having the heads done the two graphs are almost identical except that with the ported heads the torque curve stays flatter in the upper RPM's. The increase in torque combined with the RPM's gives a substantial HP increase. Really it looks to me like you're just running out of air. The mini ram shouldn't be the restriction so I would have to look at the heads / valves. They can be very good heads but to feed a 436 is gonna take a lot of air.

Also this is assuming that the A/F ratio is good across the board. You could be getting all the air you need and not enough fuel or you could actually be running rich, it's just impossible to tell without that data. It looks like a very strong motor and I'm sure you'll figure out the boggle. I think the potential is there :cheers:

CorvetteZ51Racer

Well, you have a couple of things going on here.

1) You've got some tuning issues...look at how bumpy your power curves are. They should be MUCH smoother than that.

2) I dare bet you don't have enough head flow for the RPM's you're trying to run, and can know for a fact you don't have enough cam duration. For the piston speeds you're running at 7500 RPM, you need to be running about 335 degrees of total duration (at 0 lash). Of course, that assumes you want to make your peak power higher than you are.

3) I don't know if you've run your piston speed calculations, but at 7500 rpm, you're running about 5000 FPM piston speeds which is VERY high, especially for a street motor. To give you some sort of comparison, the 2001 Ferrari F1 motor was running ~4950 FPM piston speeds, and Winston Cup open motors turn ~5400 FPM. In other words, I hope you have TOP quality rods and pistons in that motor, otherwise your motor won't last too long. Of course, if you slow it down to ~6500 RPM max, you're looking at 4333 FPM, which is acceptable for a street motor. Right now I can't see the dyno results, so I don't know how close 6500 is to your peak power.


[Modified by CorvetteZ51Racer, 4:22 AM 2/14/2003]

LT401Vette

Tom, Is that the setup with a 4L80 behind it? They do suck up some power. I too would be interested in your port size, in my opinion you have too much duration. I hope it is on a very wide lsa atleast 114. I am assuming that is through a full exhaust and I have found that much valve overlap causes power loss with an exhaust. To cracked 500 rwhp I was running 227cc heads and a 245/245 cam. That was with 405 cid. With the 436, you could use some big butt ports.
I find a lot more power with a shorter duration, but fast lobe. If you watch the .200 duration it can sometimes be longer with 10 degrees less .050 duration. That means better idle and torque along with the intake valve closing sooner to build more pressure and power. Even on my new 555 motor I am keeping duration at 252/256 and it isn't because I am scared of idle quality, that is just a bonus. I have also found that you loose less low end and street manors with large ports than with long duration. Not that I would think you would be lacking in torque with 436 ci and at that size on a small block a large enough port can be a challange.

Another thing worth following up on is intake vacuum. What size TB are you running? When I went from a 58mm to the Mono-Blade I thought I was grasping for hundreths, but picked up over 2 tenths. My best theory is that the plenum size was sized for a smaller motor running at lower RPMs, the Monoblade opens up the front. So, even though the 1300 CFM should have been more flow than it needed, it really responded.

Don't lose perspective those are some nice numbers and I bet you will be able to find enough to break that 500 mark with just some tweaking.

MSR

i don't think the curves look "bumpy." they look good, the tuning looks close enough, i'd be surprised if the fuel or spark were that far off.

which model brodix heads are those? just the exhausts are raised? or is there some sort of intake spacer to line the miniram up with raised intake runners? dunno, i know some auto-xers who used brodix heads on their CP engines, and they're always lame. their "500hp" engines in 2700lb cars don't seem to pull as hard as my friend's 390rw 3100lb mustang.

also, the cam looks too big for the compression. i built a 408 ford for someone with 12:1 compression, and we used an ultradyne solid with only 258/261 at .050", with .672" lift. it made 507rw at 6000rpm, using very short runners like with a miniram. but, those heads were very good (canfields, about 205cc intake ports after porting), small ports, excellent mid-lift numbers. the peak flow was only about 300/210, if i remember correctly. the power curve was still on the climb when i let off at 6k, but we artificially limited rpm on that engine due to having 3" main bearings and sustained open track use.

sorry about the disappointment. do you have flow numbers at .3" and .4" lift for those heads? what's the exhaust? what's the cold lash on the cam? who's cam is it? hopefully you'll find a simple fix, though i think it's probably just the overall combination with heads/cam.

Tomulrich

I will write more later...heading to work. just to hit a few points...I will alsoo put on mor e pics/info links later.

My heads are Brodix castings....CNC'd by Weldtech 238cc intake runners...they are also "hand massaged" a little....flowing 330 @ .700...low numbers are good too.

The miniram has been cut and ported it is flowing 420 cfm average runners.....this is wihout the heads.

I am running this tthrough a 4L80E converter is locked at 2500 and in third gear...

My FAST is telling me I am right on the money with the fuel A/F ratio....It has a wide band O2.......I am not sure where I am going to get the extra power....

I am running the 1300 monoblade....my cam is ground on a 114. It idles fine....but my vacuum is 6 "...I have no leaks any where....supprisinly enough my brakes work fine....no other issues concerning the vacuum..


the car did run consistant high 10's with a 1.6 60 ft time..

Keep the info coming...Thanks Tom

MSR

brodix has about 12 different castings for a sbc, which ones did weldtech start with?

what do you consider good for "low numbers?" i mean, for a head flowing 330 at .7", i'd be looking for 250cfm at .3". do you know the port volumes?

is the distributor properly synced to the FAST?

CorvetteZ51Racer

Well, the 114 LSA explains how you got such a broad powerband. Keep one thing in mind with the LSA, the wider it is, the wider the powerband AND the lower the peak numbers will be. If you were to go to a narrower LSA, you could pick up peak numbers, but you will lose some of the breadth in your powerband, and likely lose a little idle quality due to the increased overlap.

88-406

I agree with Z51Racer If I recall correctly the larger the engine the tighter the LSA could be. Don't be afraid to play around with things. It's off to a good start and it's rare to get it just right the first time out.

If we could see the flow figures for the heads someone might be able to help verify things.

KM

Tomulrich

The heads are the -10x RI. The intake ports are raised. the Miniram was customized by Wilson manifolds....$1500.00. Fits like a glove.

My flow numbers are as follows:
INT/EXH
.200 .300 .400 .500 .600 .700
142/106 206/151 264/208 302/228 325/237 330/242
Runner intake volume is 238cc

Tomulrich

The cam is from LT 1 motorsports.....same people who make the 245/245 cam hoover was running......they are making 600 HP flywheel....on there camaro..........

I will figure out something............maybe build a new engine......learning is all the fun of it......my next will be a aluminum block....18 degree heads or even 15 degree.......solid roller with super charger!!

LT401Vette

It sounds like you have about as much head as you can hope to get without going to 18 degree heads. I know I was heavily considering that myself. Then deceided it didn't really cost much more to build a big block :).
You could easily take another point of compression there. When i was running 12.6:1 compression I needed to keep tight reigns on timing, but 12.1:1 has been a cake walk and that was with the 245 cam.

I still think you would be better off with 10 degrees less duration on both sides.

What size headers are you running? 1 3/4? By your curves it almost looks like there is some type of resonance thing happening in the headers or intake from the high 5's to 7. You can see the curve was heading for more and took a step back for 1000 RPM right in the peak power area. I wonder if it could be tuned out with different length and diameter headers. I wanted to go to a 1 7/8" header for quite some time on Hoover, but never made the step. Now after building my big block headers I found it isn't so bad a job, I should have gone ahead with it.

Like you said, the fun is in the learning.

BOWTYE8

Hang in there Tom ;)
All of our first few times out dont seem to shine. You have a nice power plant there. If you do decide to take the route mentioned above.....Give me a shout......Maybe I can sneek a 436 into bowtye8! (inside bowtie bros joke)

Good to see ya Phil!

For all those interested here are some pics of Tom's reworked miniram.
http://bowtye8.tzo.com/bowtie8/corve...intakethbn.htm

Dennis

Tomulrich

My headers are actually 1 3/4 stepped to 1 7/8 with split collector( which makes each primary longer. Yeah I was wondering if a smaller cam would make more power...maybe I should use the 245/245 cam?

Bowtye......yeah we can sneak the 436 in your car......but we would need to get the numbers up.......

I am seriously thinking about milling my heads to get 12.5 CR. Wonder what increase I would show? 20 HP??

Keep the suggestions coming......hey the engine looks good!.....maybe I should go BIG block....."hoover 2"..haha.....