Jump to content

timing curves


Boosted_One
 Share

Recommended Posts

Thought I'd start up a timing curve thread.

 

Currently here is my configuration:

 

11 BTDC

34 degrees in at 3000 rpms

 

currently am running 1 dgree of retard per psi of boost past 10 psi.

 

 

Example:

15 psi would have a total timing of 29 degrees.

18 psi would have a total timing of 26 degrees.

 

I have not yet programmed the mock "vacuum advance curve". This would benefit my fuel economy at cruising and what not but has not affected my WOT runs.

 

That's what I got as of 9-15-02

 

It'll probably change in about 3 hours... LOL!

Link to comment
Share on other sites

2000 rpms ~ 10*

3000 rpms ~ 20*

4000 rpms ~ 25*

6000 rpms ~ 33*

 

The curve is steep to around 4500 then tapers off to 6K or so.

 

Very conservative IMHO. That timing should be way more advanced at 3K!

 

I got this data years ago, got a little more on the sheet if need be.

Link to comment
Share on other sites

  • 5 months later...

Where can I buy SDS?  Will it work with MSD6a?  I am going with Glen's MPI Intake...

 

The mod of my Baby is

 

1988 Conquest 5SP

.040 over

forged piston

lightweight rods

knife edge crank balance and blue printed

None jet valve w/roller camshaft

Glen's MPI intake

Garret T3/T4

South Florda Performance Header w/external wastegate (turbonitics)

Waiting of Kelly's 3" Exhaust

 

This is my every friday & saturday car with occasional race ;D  Ya right ;D ;D

 

But I Need to know what size TB I should put use

 

I want to make my baby run DIS, but I don't konw who to do it.  Can someone mentor Me Please ???

 

Also, I don't know what fuel & ignition managemet to run with.  Any suggestion is highly appreciated....

 

Thanks in advance... BooM....

Link to comment
Share on other sites

Where can I buy SDS?  Will it work with MSD6a?  I am going with Glen's MPI Intake...

 

The mod of my Baby is

 

1988 Conquest 5SP

.040 over

forged piston

lightweight rods

knife edge crank balance and blue printed

None jet valve w/roller camshaft

Glen's MPI intake

Garret T3/T4

South Florda Performance Header w/external wastegate (turbonitics)

Waiting of Kelly's 3" Exhaust

 

This is my every friday & saturday car with occasional race ;D  Ya right ;D ;D

 

But I Need to know what size TB I should put use

 

I want to make my baby run DIS, but I don't konw who to do it.  Can someone mentor Me Please ???

 

Also, I don't know what fuel & ignition managemet to run with.  Any suggestion is highly appreciated....

 

Thanks in advance... BooM....

 

AHHH, so you got Tyrell's roller cam? Or the Schneider?

Is the cam set-up, or theoretical? There is a lot more to setting one up than some people are led to believe when buying one.

You just missed the SDS GP too. Look at the GP board. Maybe you can still get in on it?

Link to comment
Share on other sites

AHHH, so you got Tyrell's roller cam? Or the Schneider?

Is the cam set-up, or theoretical? There is a lot more to setting one up than some people are led to believe when buying one.  

You just missed the SDS GP too. Look at the GP board. Maybe you can still get in on it?

 

 

What do you mean "There is a lot more to setting one up than some people are led to believe when buying one"  I know this guy in San Francisco, goes buy the name "Turbo"  His really knows his $#$%, but anyway he makes it.

 

About the TB, what MM should I go with?  65MM, 70MM or 75MM TB?(FORD TB)

 

Since I go with the SDS, do I still use my 1GMASS, or what replaces it?

 

Thanks, BooM....

Link to comment
Share on other sites

AHHH, so you got Tyrell's roller cam? Or the Schneider?

Is the cam set-up, or theoretical? There is a lot more to setting one up than some people are led to believe when buying one.  

You just missed the SDS GP too. Look at the GP board. Maybe you can still get in on it?

 

 

What do you mean "There is a lot more to setting one up than some people are led to believe when buying one"  I know this guy in San Francisco, goes buy the name "Turbo"  His really knows his $#$%, but anyway he makes it.

 

About the TB, what MM should I go with?  65MM, 70MM or 75MM TB?(FORD TB)

 

Since I go with the SDS, do I still use my 1GMASS, or what replaces it?

 

Thanks, BooM....

 

 

Tim means some cams you can't just throw the 1.5 rockers and a "roller" cam in and be done with it.

 

If you see Tyrrell ask him where my $200 is if you could. See if he can tell the difference between an 87 and 89 tranny that he stiffed me on.

 

65mm TB works good. Don't want to go too big.

Link to comment
Share on other sites

I know this guy in San Francisco, goes buy the name "Turbo"  His really knows his $#$%, but anyway he makes it.

 

Not trying to start any wars, but I've found him to be "technically challanged". His info is usually bogus. He claims to know these cars inside and out, but when asked about specific details he fills my ear full of some of that "$#$%".

 

Never believe someone that can't provide hard data (Timeslips 1st, dynosheets 2nd, and a car that runs for more than 3 months a close 3rd).

 

Joel

Link to comment
Share on other sites

Tyrell's cam is more of a generic grind. He basically has the stock lobes made into roller lobes, and takes just enough off the base to accomplish that barely. Not a bad idea, but it isn't the best performer according to his specs.

He makes it sound easier than it is in most cases. You will need HD springs for any cam you run(to a certain lift), since they are cheaper than stock, and better. Whenever the stock cam is reground into a hydraulic roller, the base needs reduced to do it. Doing so requires mods to regain the loss of base some other way. Does he help you do that? Even a worn stock set-up requires similar mods, to keep the lifters from ticking. Reduce the base, and it will tick worse.

 

Back to timing curves:

I would think there are quite a few more variables that are different on each engine combo, and what is the target application too. Like dragsters weld the weights in place, remove them, etc...

What type of fuel, boost, CFM, ignition, compression ratio, etc...

I would say your numbers to try are a good place to start. I like to bump the base up 4 degrees at a time, and when it knocks, back off 2 degrees, and also try different springs, & weights. However, I don't know of anyone with a kit for our engine? Then you can start increasing base again with the boost retard. I've never done it on these engines, so I have a lot to learn here. Keep track of your adjustments, and results for us?

Link to comment
Share on other sites

65mm TB works good. Don't want to go too big.

 

I know it not timming curves but whats the down side when your TB is too big?  I'm going 70mm with my intake here in the near future and thats only because my intake is 70mm. I have a 75 but I don't want to remove the intake to machine it.

Link to comment
Share on other sites

If the TB is too big, just crack it open a little and it'll boost up too fast, not good for street driving.

About timing, my stock distributor is showing only 30 degrees @ 3500 with a 10 degree baseline (boost retard disconnected).  I'm going to get a spring kit for a 350 chevy and see if I can get an extra 5 degrees out of it @ 500 rpm less.  I'll make sure to post results, it'll be a few weeks.

Nate

Link to comment
Share on other sites

If the TB is too big, just crack it open a little and it'll boost up too fast, not good for street driving.

About timing, my stock distributor is showing only 30 degrees @ 3500 with a 10 degree baseline (boost retard disconnected).  I'm going to get a spring kit for a 350 chevy and see if I can get an extra 5 degrees out of it @ 500 rpm less.  I'll make sure to post results, it'll be a few weeks.

Nate

I thought about the Chevy kit thing too. Looks like it would work. Good idea. I will be watching to see how that works for ya.

Link to comment
Share on other sites

  • 7 years later...
Bumping this up b/c it needs more discussion. Luisitoturbo's car got my gears turning again about the stock mechanical weights and distributer advance. Does anybody else have data that shows the timing curve for a stock SQ? It's a good baseline for the MPI guys.
Link to comment
Share on other sites

 Share

×
×
  • Create New...