Motor builder question?

[Speedfreak]

Can a motor be built to handle an extreem amout of timing. For an example 200 PSI compression MSD enhanser and 3 degrees of static timing advance? On pump gas? I know no WOT at all unless you have a major retard in timing in the upper rpm. And I know that TL systems give you a bunch more timing on pump gas. But when porting a motor can you port is for a specific amount of timing? I guess that is my question. Is a motor built for a specified amount of timing?

I don't understand the whole port timing thing. But a buddy of mine that builds race engines is trying to explain it to me but I just don't get it...

Help!!!!!

Another question what is the most timing you can run with TL I know that 30 degrees is max available. Has or does anyone run 30 degrees of timing?

 

[crammit442]

This should be interesting.........opcorn::smile:

 

[jetskiking]

My guess would be yes that a motor could be built for certain timing given that compresion, stroke, rod length, and other factors play a role in setting up a timing curve :dunno: . I am definetly not an expert and have also been curious about running the MSD with an advance but I was thinking more around 180psi of compression. I definetly think that 200psi is pushing the limits of pump gas on any motor if not passing it with an advanced timing. I'm wanting to hear peoples input and experiences .

 

[#ZERO]

I know of a few people including myself that are running about 205 PSI compression with a MSD enhancer and 3 degrees of static timing advance with no deto problems. It also helps if you port your b-pipe exhaust manifold to 47mm or more and run the exhaust system almost dry. Your squish band and dome diameter also play a big factor in how much compression you can run. Most pump gas engines tend to like a couple of degrees of squish angle with a wide squish band widths and smaller diameter domes with more volume. Race gas engines like a narrow squish band widths and larger diameter domes with less volume. If you want to push it to the limits be prepared to pay the price for it one day.

 

[Big Kahuna]

This should be interesting.........opcorn::smile:

I thought you would have given him a good explanation............

Got any butter in the popcorn?

 

[Speedfreak]

I was looking up the MSD enhancer timing curve and it sets the timing advance about 22 degrees so with a 3 degree static advance that is 27. And a MSD TL the max is 30 as far as I can tell. So your still under that.


O and B pipe is at ported to 49MM

 

[Matt_E]

Eh....I am pretty sure that TL goes quite a bit futher than 30 degrees, buddy. :biggthumpup:

I used to run 35 degrees initial advance, and there was more room.
I currently don't have it installed, but I ran it half of last season on 29 degrees initial, and that was sort of middle of the road.

 

[Speedfreak]

Eh....I am pretty sure that TL goes quite a bit futher than 30 degrees, buddy. :biggthumpup:

I am talking about the digital TL. The directions which are vague says on page 7 that the max timing range is 23 to 30 degrees and that the 3 dip switches are used to retart the timing 1 to 7 degrees from the 30 mark. Correct me if I am wrong but I was just going by the instllation instructions. I don't even have a setup yet. And on page 4 is has the 3 dip switches and how to setup the max to -7 degrees

 

[Matt_E]

That means you can take off 7 degrees from the static timing without moving the pickup plate.

I guarantee the range is a bit further than 30. When I reinstall mine, I'll check what the max is. I would guess 40 at least.

 

[SUPERTUNE]

I think the MSD plate will go close to 50 degrees...

 

[Speedfreak]

That means you can take off 7 degrees from the static timing without moving the pickup plate.

I guarantee the range is a bit further than 30. When I reinstall mine, I'll check what the max is. I would guess 40 at least.

I see.... I was thinking with the timing marks lined up it would only give you that amount. I wasn't thinking of doing it manualy. Since it was a digital system I thought it was all done digitally. Like burning a new program in a truck computer.

Gotcha.

 

[egbrig]

To set things straight: Porting is a way to set the port windows of the cylinder to a size which will flow the required volume of charge to allow the engine to make power at the needed rpm or rev. range. An engine is not ported for timing. Timing of the start of the flame kernal is depentant on several factors, ie: stroke, bore, rod length, the way the charge will fold in layers (head design big factor of the folding) Pipe design has big influence. There are a few more in depth things. You want the peak cylinder pressure to be achieved about 12-14 degrees ATDC, so you initiate the flame at the degree in which it will achieve the peak pressure. Setting timing to a number simply because. is not the way and will not give peak performance. Different setups will require different timings. An engine built for acceleration vs. top end would use the same basic timing the difference would be because the ignitions we mostly use aren't capable of giving the timing curves we need (a Vilder can), but also the way in which an engine is utilized will also determine the timing curve required. If setting advance to high on the lower rpm range you will actually loose power because your peak pressure arives to soon and the piston actually fights itself past TDC. The other issue is, if you have perfect timing and correct a/f ration then you have an engine which runs making the peak heat all the way through the rpm band and it will stick being not able to get rid of the heat fast enough. Start with a conservitive timing setting and increase till you loose what your after or it sticks. Hopefully you'll feel the loss and reduce from there.