416" on the dyno

[TT5.9mag]

Huh?
Having the convertor hit a few hundred over peak torque is where its at. I try to do exactly that. And in 50 odd years of racing( with a few gaps here and there), never wacked a ring or a plug.

Sorry I meant “more” not “less”, corrected.

 

[Newbomb Turk]

Usually guys with race cars have more octane than they need. And if they lock their distributor and set the timing at idle they’re a few degrees short at 6500. That’s why their engines live. Once you start to tune on stuff with a very narrow tuning window (big boost on gasoline for example) you learn very quickly that too much timing at peak torque can and will destroy stuff. What’s crazy is backing stuff down makes the car faster, but it’s hard to get people to do that. I learned by blowing crap up. Then asked the guys making a bunch more power than me. Then went to the dyno and questioned Brule till I was blue in the face (and he was mad at me). It matters. Just because stuff doesn’t blow up doesn’t mean it’s right.

I was working with a guy on the phone. We were going back and forth on a curve and he said I know it’s happy because it’s not hurting parts.

One day he sent me a video of him pulling some plugs and such and I saw he had a catch can on his PVC system.

So I said pull the dipstick on the can and tell how much oil is in the can.

And he says I just dumped it because it was full. So I said how many runs does it take to fill it, and he says 8-10 passes or about every 500 miles.

I convinced him to do a PCV and the can but had forgotten about.

And I said you are hammering the rings to death. You can’t hear it and it may not be showing on the plugs but your timing is killing your ring seal and it’s showing up as oil in the catch can.

He finally got a pretty good curve in it and he could make a hundred runs and there was just a light film of oil on the bottom of the can.

That’s just one canary in the coal mine to clue you in to how the rings are sealed.

He was hammering the rings to death. Had he not had the PVC and catch can on it he would have eventually killed the rings to the point they just stopped sealing except for the minimum.

Just because you aren’t killing parts in a run or two doesn’t mean you aren’t compromising something.

 

[92b]

I’ve only had one box that had so little retard so late it didn’t matter.

Have you tried a fast box with a fast distributor?

You can not determine what the engine wants for timing making power sweeps.

Why not?

You can rev the engine e to death with no load on it and you can keep adding timing.

Not sure what you mean but I don't think we are on the same page here.

 

[Newbomb Turk]

Have you tried a fast box with a fast distributor?


Why not?

Not sure what you mean but I don't think we are on the same page here.

Fast as in FAST?

You can tell what doing a sweep with timing? Certainly you can make a timing change on a sweep and see a change in power, but that doesn’t tell you MBT. You have to load the engine down, steady state and change the timing while loaded to see what that is.

 

[92b]

Fast as in FAST?

Yes, or crane.

You can tell what doing a sweep with timing?

I think you mistyped this. Not sure what you mean.

Certainly you can make a timing change on a sweep and see a change in power, but that doesn’t tell you MBT.

What is MBT?

You have to load the engine down, steady state and change the timing while loaded to see what that is.

Why does the motor have to be loaded steady state? It's loaded when it is swept. How is that different?

 

[Newbomb Turk]

Yes, or crane.

I think you mistyped this. Not sure what you mean.

What is MBT?

Why does the motor have to be loaded steady state? It's loaded when it is swept. How is that different?

I have tested one Crane box. It retarded.

I was asking you how can you determine what the timing should be at any point in the rpm range with a sweep? How do you know of the engine wants more or less timing at a certain point in the curve?

MBT is minimum spark advance for best torque.

 

[92b]

I have tested one Crane box. It retarded.

You need to use the crane or fast distributor with it.

I was asking you how can you determine what the timing should be at any point in the rpm range with a sweep? How do you know of the engine wants more or less timing at a certain point in the curve?

Right or wrong here is how I do it with a locked distributor. I'm assuming if it's a locked distributor it is a race car or a race car that gets driven on the street.
I start by watching the timing curve as I rev the motor through the expected rpm range. I note if or how much and where it retards in the rpm range. I start on conservative side of the expected timing and set it at the middle of the working rpm range. Example: 602 crate motor in a circle track application is 4000 to 6200 rpm. I will set timing at 5000 rpm.
I will start conservative and make the pull starting below the expected rpm range. Next I will go down 2 degrees.
It is safer to find where it looses power by going down in timing first.
Next I lay the power curves over each other and see where the power differs across the rpm range.
When laying the cuves over each other your going to see places where changing the timing a couple degrees doesn't effect it at all. Some combinations are more sensitive to timing and some are less sensitive.
Anyway, If it gains power on both ends that's easy go down 2 more degrees and pull it again. Look at the curves and compare. eventually it will loose power somewhere usually on the upper end first when going down but not always. Sometimes it will loose at both ends at once.
This is usually with a locked distributor that doesn't retard much and a motor / carb that works well. But let's say it starts loosing power on the top end and stays the same on the bottom.
Next I would drop 2 more degrees and see if the if the bottom drops. Let's say it does now I know what the bottom of my curve is.
Next if the power dropped on the high end on the first timing change. I will go up 2 from initial and see if the high end goes up. Let's say it stays the same. Now I know where the upper limit is.
I usually shoot for the least amount of timing that doesn't loose significant horsepower to keep a little cushion depending on the application and customer. Not quite enough timing might lose a little power A little too much timing might break something. If you are going to correct for all the varibles that can affect your tune then you can trim your cushion to whatever you can afford. Next I'm going to look at my power curves and see if there is a significant gain to be had that is going to justify the expense and extra maintenance of having a curve put in a distributor. If you are doing this with a computer that will probably be easier for some to do and you should have all the info you need For a starting baseline curve.
Most of my customers don't have that option. Rules don't allow. Building a timing curve that gives you what little timing advance you will need at the rpm you will need it is not as easy as it sounds and unless you are going to do it yourself you are going to have to pay someone to do it.
At some levels of competition you might have to do it to get that last little bit. If the option is to keep it locked then I might have to compromise because you can’t give it what it wants on both ends so you compromise and make it safe. I know you claim there is a lot of horsepower to be gained by unlocking every motor but my experience is different.
For example on a 602 crate you might get 4 hp. Still, not bad but for some poeple the juice isn't going to be worth the squeeze. On a 350 spec motor with a good carb and a FAST ignition system you probably wont get anything. I don't usually see the kind of power gains you talk about. Maybe we are just seeing different extremes of applications. That's a possibility.
For some of my customers simplicity and cost reign over having that last bit of power. And they are quite successful doing it that way. For others it's no holds barred.
In the end I just try to do what is going to be best for my customer considering the circumstances.

 

[Mean416]

@rmchrgr very cool build. Nice to see pretty big numbers posted out of stock layout heads! Just another data point in favor of the bloomers.

I totally understand not feeling the need to tweak every last ounce of power out of the combo, especially if the rest of the car isn't built, and given it's not a straight up drag car anyway.

You can always tweak timing and setup later on if desired.

What's going on with the rest of the car?

 

[rmchrgr]

@rmchrgr very cool build. Nice to see pretty big numbers posted out of stock layout heads! Just another data point in favor of the bloomers.

Thank you!

I totally understand not feeling the need to tweak every last ounce of power out of the combo, especially if the rest of the car isn't built, and given it's not a straight up drag car anyway.

You can always tweak timing and setup later on if desired.

If it spins off the line at the track I can take some timing out through the Holley software.

What's going on with the rest of the car?

It's been apart for a long time. You can read all the boring details below.

Orange car

 

[Newbomb Turk]

You need to use the crane or fast distributor with it.

Right or wrong here is how I do it with a locked distributor. I'm assuming if it's a locked distributor it is a race car or a race car that gets driven on the street.
I start by watching the timing curve as I rev the motor through the expected rpm range. I note if or how much and where it retards in the rpm range. I start on conservative side of the expected timing and set it at the middle of the working rpm range. Example: 602 crate motor in a circle track application is 4000 to 6200 rpm. I will set timing at 5000 rpm.
I will start conservative and make the pull starting below the expected rpm range. Next I will go down 2 degrees.
It is safer to find where it looses power by going down in timing first.
Next I lay the power curves over each other and see where the power differs across the rpm range.
When laying the cuves over each other your going to see places where changing the timing a couple degrees doesn't effect it at all. Some combinations are more sensitive to timing and some are less sensitive.
Anyway, If it gains power on both ends that's easy go down 2 more degrees and pull it again. Look at the curves and compare. eventually it will loose power somewhere usually on the upper end first when going down but not always. Sometimes it will loose at both ends at once.
This is usually with a locked distributor that doesn't retard much and a motor / carb that works well. But let's say it starts loosing power on the top end and stays the same on the bottom.
Next I would drop 2 more degrees and see if the if the bottom drops. Let's say it does now I know what the bottom of my curve is.
Next if the power dropped on the high end on the first timing change. I will go up 2 from initial and see if the high end goes up. Let's say it stays the same. Now I know where the upper limit is.
I usually shoot for the least amount of timing that doesn't loose significant horsepower to keep a little cushion depending on the application and customer. Not quite enough timing might lose a little power A little too much timing might break something. If you are going to correct for all the varibles that can affect your tune then you can trim your cushion to whatever you can afford. Next I'm going to look at my power curves and see if there is a significant gain to be had that is going to justify the expense and extra maintenance of having a curve put in a distributor. If you are doing this with a computer that will probably be easier for some to do and you should have all the info you need For a starting baseline curve.
Most of my customers don't have that option. Rules don't allow. Building a timing curve that gives you what little timing advance you will need at the rpm you will need it is not as easy as it sounds and unless you are going to do it yourself you are going to have to pay someone to do it.
At some levels of competition you might have to do it to get that last little bit. If the option is to keep it locked then I might have to compromise because you can’t give it what it wants on both ends so you compromise and make it safe. I know you claim there is a lot of horsepower to be gained by unlocking every motor but my experience is different.
For example on a 602 crate you might get 4 hp. Still, not bad but for some poeple the juice isn't going to be worth the squeeze. On a 350 spec motor with a good carb and a FAST ignition system you probably wont get anything. I don't usually see the kind of power gains you talk about. Maybe we are just seeing different extremes of applications. That's a possibility.
For some of my customers simplicity and cost reign over having that last bit of power. And they are quite successful doing it that way. For others it's no holds barred.
In the end I just try to do what is going to be best for my customer considering the circumstances.

You need to use the crane or fast distributor with it.

Right or wrong here is how I do it with a locked distributor. I'm assuming if it's a locked distributor it is a race car or a race car that gets driven on the street.
I start by watching the timing curve as I rev the motor through the expected rpm range. I note if or how much and where it retards in the rpm range. I start on conservative side of the expected timing and set it at the middle of the working rpm range. Example: 602 crate motor in a circle track application is 4000 to 6200 rpm. I will set timing at 5000 rpm.
I will start conservative and make the pull starting below the expected rpm range. Next I will go down 2 degrees.
It is safer to find where it looses power by going down in timing first.
Next I lay the power curves over each other and see where the power differs across the rpm range.
When laying the cuves over each other your going to see places where changing the timing a couple degrees doesn't effect it at all. Some combinations are more sensitive to timing and some are less sensitive.
Anyway, If it gains power on both ends that's easy go down 2 more degrees and pull it again. Look at the curves and compare. eventually it will loose power somewhere usually on the upper end first when going down but not always. Sometimes it will loose at both ends at once.
This is usually with a locked distributor that doesn't retard much and a motor / carb that works well. But let's say it starts loosing power on the top end and stays the same on the bottom.
Next I would drop 2 more degrees and see if the if the bottom drops. Let's say it does now I know what the bottom of my curve is.
Next if the power dropped on the high end on the first timing change. I will go up 2 from initial and see if the high end goes up. Let's say it stays the same. Now I know where the upper limit is.
I usually shoot for the least amount of timing that doesn't loose significant horsepower to keep a little cushion depending on the application and customer. Not quite enough timing might lose a little power A little too much timing might break something. If you are going to correct for all the varibles that can affect your tune then you can trim your cushion to whatever you can afford. Next I'm going to look at my power curves and see if there is a significant gain to be had that is going to justify the expense and extra maintenance of having a curve put in a distributor. If you are doing this with a computer that will probably be easier for some to do and you should have all the info you need For a starting baseline curve.
Most of my customers don't have that option. Rules don't allow. Building a timing curve that gives you what little timing advance you will need at the rpm you will need it is not as easy as it sounds and unless you are going to do it yourself you are going to have to pay someone to do it.
At some levels of competition you might have to do it to get that last little bit. If the option is to keep it locked then I might have to compromise because you can’t give it what it wants on both ends so you compromise and make it safe. I know you claim there is a lot of horsepower to be gained by unlocking every motor but my experience is different.
For example on a 602 crate you might get 4 hp. Still, not bad but for some poeple the juice isn't going to be worth the squeeze. On a 350 spec motor with a good carb and a FAST ignition system you probably wont get anything. I don't usually see the kind of power gains you talk about. Maybe we are just seeing different extremes of applications. That's a possibility.
For some of my customers simplicity and cost reign over having that last bit of power. And they are quite successful doing it that way. For others it's no holds barred.
In the end I just try to do what is going to be best for my customer considering the circumstances.

Im not sure what difference the distributor makes. A simple points distributor doesnt retard with rpm. I can test any ignition with that.

Neither does a Unilite retard with rpm. So I have tested and qualified that the distributor doesn’t continue to retard. THEN I use the customers distributor and verify that.

As for your above example, these cars you use as an example never run under caution? What about on the restart?

I know what you are doing. If the customer won’t pay for me to actually test for MBT then I do about what you do. It is what it is. But you can’t tell me that you know that at 5000 and 6000 what it needs for MBT because you can’t do that with a sweep test.

Unless these cars run on a very fast 1/2 mile I never see 1200 rpm from corner exit to corner entry. And that would be down the front and back stretch. Between 1 and 2 and 3 and 4 the rpm is nowhere near that high. At least at the tracks in my area.

How do you account for that?

I get doing what’s “best” for the customer. It always sounds good. Makes people feel warm and fuzzy. I try myself. I can’t force guys to do certain tests. I can’t force guys to let me test their ignition system before it goes on the pump. It’s hard to get them to even bring their ignition system to the dyno to test with it. Because that’s what SHOULD be SOP. But it’s not because guys read **** like this and think it doesn’t matter, but it does because again, aside from stand alone systems all these ignition boxes retard. If you don’t account for that you have no idea where the timing is at any given rpm.

The hard fact is the customer isn’t always right. It is THEIR a money and Im more than cognizant of that fact.

The truth is it’s not just the money spent for a day on the dyno. It’s general maintenance and TBO and all that adds up.

BTW, where is peak torque and peak power on a 602?

 

[rmchrgr]

Get offa my lawn!

 

[Newbomb Turk]

Get offa my lawn!
View attachment 1716472296

So a discussion is out of the question because you aren’t involved?

If you don’t care dont read it.

 

[rmchrgr]

Start your own thread!

 

[Newbomb Turk]

Start your own thread!

Whatever.

 

[92b]

Whatever.

Start a thread and we can discuss it there. If the op doesn't want us messing up his thead I'll respect that. Send me a link. Copy and paste post 85 and we can pick up from there. Or maybe a mod can move it. I want to hear your thoughts on the subject.

 

[rmchrgr]

Start a thread and we can discuss it there. If the op doesn't want us messing up his thead I'll respect that. Send me a link. Copy and paste post 85 and we can pick up from there. Or maybe a mod can move it. I want to here your thoughts on the subject.

Thank you!

 

[TT5.9mag]

@92b
@Newbomb Turk

Continuing ignition timing debate from the 416 thread.

 

[mopowers]

What an awesome build! I can't wait to see this beast in action, even with the missing couple HPs from an imperfect timing curve.

 

[gzig5]

What an awesome build! I can't wait to see this beast in action, even with the missing couple HPs from an imperfect timing curve.

Good thing he didn’t mention what oil he was running.

 

[mopowers]

Good thing he didn’t mention what oil he was running.

Ain't that the truth.

 

[rmchrgr]

What an awesome build! I can't wait to see this beast in action, even with the missing couple HPs from an imperfect timing curve.

Yeah, somehow I think it's going to be OK.

 

[rmchrgr]

Good thing he didn’t mention what oil he was running.

God forbid. I haven't brushed up on my API ratings in a long time.

 

[RustyRatRod]

Well for what it's worth, I like the build and the power numbers. Nice job.

 

[rmchrgr]

Thank you RRR.

 

[MOPAROFFICIAL]

Thanks. I'll agree with what you said to an extent but there were a number of factors that prevented that first version from making the power I hoped it would and it wasn't the heads. I didn't only change the heads for round two, the whole thing is different now. Regardless, if you go by the adage that says power = double the head flow then the IMM-RHS heads should support at least 600hp.

As I said in my first post, the goal 10 years ago with the RHS heads was 525hp. I would have done cartwheels if it made that. In reality there wasn't a huge difference between my stated goal and what it actually made but it was enough to make me want to go back and improve on it. I would have liked to have had some seat time with that version of the motor but it just wasn't meant to be.

The exhaust ports on the RHS heads were essentially untouched so figure the BPEs likely flow more on that side. I'm not sure if there is even room for a larger exhaust valve on the RHS heads. Maybe Brian will chime in here and let us know if that's the case but it's not terribly relevant to this thread. Either way, the RHS are good heads especially with the IMM CNC program - he had them flowing 293 CFM. They weigh about 800lbs each though so switching to aluminum castings shaved a bunch of weight off the front and up high. Trust me, that was not a small part of the decision to go with aluminum.

The intake port openings on the BPEs are larger than any head I've ever laid eyes on so that might account for something but I honestly don't know what they flow. Far as I can tell, Rod does not publish that info because it just creates unnecessary B.S.. It's not always about the biggest number anyway.

The pushrod pinch area is where the BPEs shine because they essentially have no pinch at all. The pinch is the Achilles heel of any standard-port LA head and is why the factory created the W stuff. If you think about it from that perspective, the BPEs are kind of the best of both worlds - basically no pushrod pinch yet no need for offset rocker gear.

All anyone needs to know is that the BPEs are very efficient and will obviously support well over 600hp. IMO they are the current pinnacle of standard LA stuff. If you want or need to make more power with a small block you're looking at much more expensive parts.

Maybe someone will crack 700 or more with a set of BPEs but that's going to take compression, a tricked out intake, big roller cam, 2 1/4" headers and an 1,150 Dominator. Race motor stuff.

Cfm x2 =hp, yes in theory.. though some have made more power than that.. because yes, it isn't just cfm that makes power, its also distribution / wet flow, chamber shape and port volume and so on. The port can flow x amount, but if the air grabs all the fuel and sends it down the chamber wall.. now how much power are you making. The issues with poor distribution that arise ..like detonation sensitivity and so forth, heat and the flame travel...so thats a important factor to consider.
The rhs would probably make a higher peak hp on a 360 cid motor relative to cid than say... a 410-426 cid. They will act bigger like most heads, on a smaller stroke.. but 4" eats more than they ideally provide In one gulp. The intake is another issue with most not flowing what the head flows , theyre corks...
This is why its easier realize the 475-500 hp when building around a 250 cfm head 'cid aside' when it comes to the off the shelf selection of manifolds ..because they all flow near that anyways.
Rhs are great heads for 300-379 cid motors and even say 500 or so hp street 4" motors.. but will take a big *** cam to feed 400+cid near its full potential and still falling short Imo. Brian's program is great and I know they'll allow any 300-379 cid to breathe fire. We aren't talking people or pride though, just heads.
Doing a lot with a little is great, a brag to an extent.. but there's a point where youre just fkn around ego stroking trying to squeeze that last drop from the turnip None the less.. its a fun and exciting hobby...