not trying to set a curve per say. just new to this grid stuff and didn't no if having a different value than your actual ignition timing ( the motor is set to 34 but the grid value is at 37).

quote:

Originally posted by DRB Motorsports:
not trying to set a curve per say. just new to this grid stuff and didn't no if having a different value than your actual ignition timing ( the motor is set to 34 but the grid value is at 37).

MAX timing should be set to the same as what the engine is set to- in your case, 34 degrees..assuming you've got your distributor locked out, and a timing light shows 34 degrees on the balancer.
To check, click on Ignition Timing tab, then click on Engine RPM tab. Delete all of the numbers out of the "Engine RPM"-"Ignition Timing" table. Then enter 0 in the first line of the first column, and enter 34 in the first line of the second column. Crank the engine, and set timing to 34 degrees on the balancer. This just 'synchs' your actual ignition timing and your Grid ignition timing- so that the timing is actually at 34 when the Grid 'thinks' it's at 34.
After you've got that set, you can set Main Timing the same as Max Timing if you want, or a couple degrees less if you want to advance timing for whatever reason. Usually, I've got mine set up to retard 15 degrees below 700 RPM for a start retard, then at 750 rpm it goes to 36. My max timing is set to 40, which gives me the capability to advance timing 4 degrees if that's what I want to do. Or you can retard timing (depending on what your max retard is set at, mine's 15 degrees retard) if you want.
Maybe that's not too confusing..

Electric or belt fuel pump? You are getting to a power level that it becomes really hard to keep the carb full of fuel with an electric.

Belt 0.5 pump

quote:

Originally posted by DRB Motorsports:
not trying to set a curve per say. just new to this grid stuff and didn't no if having a different value than your actual ignition timing ( the motor is set to 34 but the grid value is at 37).

What was posted previous about the Maximum Timing Reference and the Main Timing being programmed to the same value is very important when setting the timing with a light. I’ve seen racers have this programmed wrong and Grid is in retard when the timing was set.

Remember this. Grid “cannot” advance timing greater than what the Maximum Timing Reference is programmed to and the actual static timing of the engine.

If you do not download the data acquisition often I recommend turning it OFF. It’s just wasted data taking up space imho.

To program the data acquisition Start Recording I suggest Engine RPM Above 3000, AND Launch Input. In Stop Recording, Engine RPM Below 1500, OR = None, Post Trigger time 1 second, Max Recording Time 15 seconds.

For what its worth the old cam before the motor popped was a crower E62077 : .788/.716 284/298 LC 115 installed on a 111. It has BMF 405's on it for cylinder heads at the time.

Still surprised guys pick there own cams. Builders like Reher-Morrison and others had done all the testing in the world already..

I didnt just pick one. Cylinder head manufacturer stated they use company A, to call them cause they get their cams for their heads from them. I listened to the experts.

This message has been edited. Last edited by: Mike Frizie,

quote:

Originally posted by markemark:
If you do not download the data acquisition often I recommend turning it OFF. It’s just wasted data taking up space imho.

What's the harm in that? If something weird happens on a pass, at least you'll have the opportunity to pull the data.

ok . im at a loss. since I last posted . I installed a new camshaft to this engine. 278/300@50, 900/890 lift, with a 114 lc installed to 112 per the cam card. and absolutely no change?! id been with any change good or bad. but ran exactly the same. fuel pressure is good. compression is the virtually the same on all cylinders. leak checks ok. O2 data shows my my afr at the stripe is 5-6 (alky and I don't have the decimal setting set correctly to see the tenths). converter drop back on the shift is 600 rpms. still only going 4.85-87 @ 140. 1950lbs 4 link dragster with 15-35 big bubba and 4:10 gear. 582 inch motor to recap. wtf am I missing?

Built a 582 . Seems kinda off/slow. Rfd 24-b, 383cfm heads. 15:1. Cam specs are 900/855, 282:292@.050,113 lobe center insralled to 109 per cam card. 1950lb dragster, 4.10 with mt 15/35/16,s.apd 1250 alky. Ign timing @34.Best mph 140/141 so far. Thoughts? Comments?

Now you went to a 278/300 .900/.890 114 cam.

First the heads aren't 383 CFM, betting that's the CC of the intake runner!

Second, your original cam was not bad! So I don't know what you were expecting. Without more details of what the combo and more specifically the rpm range your turning the motor anything else is just a guess other than why did you take intake duration away?

BBC love lift, you had good numbers there to start with. Ex lift is much less sensitive in your combo so the added lift did nothing.

You stated it's slow and I agree but the original cam nor the second is the real reason. Something else is not in sink with the combo! This motor should make 1000 hp easy and I'd ballpark your at 850 ish. There is no cam out there that will give you another 150 HP...

quote:

Originally posted by DRB Motorsports:
ok . im at a loss. since I last posted . I installed a new camshaft to this engine. 278/300@50, 900/890 lift, with a 114 lc installed to 112 per the cam card. and absolutely no change?! id been with any change good or bad. but ran exactly the same. fuel pressure is good. compression is the virtually the same on all cylinders. leak checks ok. O2 data shows my my afr at the stripe is 5-6 (alky and I don't have the decimal setting set correctly to see the tenths). converter drop back on the shift is 600 rpms. still only going 4.85-87 @ 140. 1950lbs 4 link dragster with 15-35 big bubba and 4:10 gear. 582 inch motor to recap. wtf am I missing?

First two things is that the big bubba AND 4.10 gear is extremely hurting you IMO.. In my car I have the little bubba (34/13.5) and 4.30's.. Third, I would look at maybe advancing the cam 2*... The new motor I am working I was reccommended by Reher Morrison to advance the cam 2* from what cam card says, was told thats almost what they do on every engine..

We swapped cams because everyone we spoke to insisted our exh duration was way to small. and yes , the heads are 383 intake volume. I think they advertised 495 cfm @ .900 lift maybe? Who knows. Lil bubbas on the way.

Can you tell me what your cranking compression is?
What's your average 60' times?

1.105-1.114 ish. thinking the cranking compression was 220-230.

You have multiple issues.

That second camshaft is completely wrong as well. Not even in the ball park.

Regardless of camshaft, you have the gearing off. You don't make nearly enough power for a 4.10 and the rollout that the little bubbas have. You can keep your little bubbas, but at the least you'll need a 4.30 at a minimum.

Is this a 9.8 or 10.2 deck engine? That will determine the correct LSA, and even given the 10.2 deck height, your LSA on your last camshaft is still not enough. Your intake opening and closing events now, as opposed to the camshaft before will give you even greater cylinder pressure. Your moving in the wrong direction.

quote:

Originally posted by DRB Motorsports:
1.105-1.114 ish. thinking the cranking compression was 220-230.

What can we do to make sure your cranking pressure is 220-230 ?

If you shift @ 7300 what does it go through the lights at ?

quote:

What can we do to make sure your cranking pressure is 220-230 ?

I measured every cylinder with a compression tester right before I swapped camshafts just to make sure I didn't have a weak cylinder. PM Sent imakehp.

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That second camshaft is completely wrong as well. Not even in the ball park

Since two established engine builder/cam companies are wrong, care to share what the correct cam should be?

Mike,

Here's the cam I used in my old 565 with Brodix HH heads about 9 years ago that went 7.20's - 7.30's in a 1925lbs dragster. Ran a Ron's terminator on this combo. 1/8 mile 4.59 to high 60's @ 148 to 150 MPH. 4.10 gears w/33.5" tall tires.

Comp Cams
1718 intake lobe 318/285/.470"
1966 exhaust lobe 336/298/.450"
LS=112 degrees
1.75 rockers

Your first cam is close to this except more lift so it's not that far off! but your only showing 850HP based on your performance! Something else is wrong! You can try a 100 more cams and its not going to fix your issue! Yes the Big Bubba's are not helping either. For the hell of it, try some ones smaller tires just to see what happens but I'd bet you still won't be were it should be.

quote:

Something else is wrong!

I agree . Just wish I could figure it out. got some little bubbas on the way so we'll see. for what its worth, we put my 555 from hardtail car in this one when we bought while were finishing the motor. Granted the hard tail weighed 1800 with my fat ass in it, it had a 4.10 rear gear with mt 3080's (15/33's). it ran mid to low 4.80's@143. with the heavier car best it could average was 4.95's@ 137.