Taking the Camaro to the race track today!

[stovebolts]

stovebolts, If ya asked me about three years ago I could have sent my 500 dollar digital timing light. it had both tach and timing.

The car was still being put together 3 years ago... Tuning it wasn't even in focus. Actually, 3 years ago it was still stripped down to bare metal literally rusting in my garage. I was so fed up I was going to just sand it, primer it and paint her flat black and be done with it just so I could drive it. I came home on my birthday and my wife had a bunch of friends over (one who was going to help me do the body work) and I went out to the garage and the car was gone! She actually had somebody come take my car for paint!

I figured last year was the summer to break the engine in, so I wasn't too concerned about getting it tuned it real good but now that the rings are seated (they are chrome molly) I'm ready to rock.

But yeah, I wish I had your timing light! I'm heading out to the pawn shops to see if I can find one...

 

[stovebolts]

The internet saves the day again. Glad the PDF helped.

Sounds like you got it nailed. Good luck at the track!

Thanks Jethro! I did find a few good articles, but nothing as complete as what you found. Can I ask which search engine you used (google, bing, yahoo) and what you used as key words?

 

[stovebolts]

I understand that. but the timing Is set at idle and then the ecm modulates it.

You know way more about this than I do, but does the ecm work with the O2 sensors in regard to timing? I know the 02 sensor starts to act as a temperature gauge at a particular point which can be used to gauge if the timing is too far advanced (running hot) or within range (timing correct). Where it gets tricky is running hot can also be correlated to running lean so is this where the second o2 sensor comes into play?

In simplistic terms, how does the ecm regulate perfect timing under all driving conditions and what sensors does it get it's information from? I'm kinda curious.

 

[Jethro Bodine]

The internet saves the day again. Glad the PDF helped.

Sounds like you got it nailed. Good luck at the track!

Thanks Jethro! I did find a few good articles, but nothing as complete as what you found. Can I ask which search engine you used (google, bing, yahoo) and what you used as key words?

Found it!

I put "how to determine spark advance with a performance cam" in the AVG search bar:

http://isearch.avg.com/search?pid=avg&sg=0&cid={cb0f1bbf-9bec-466f-96e2-da630ef6c0fc}&mid=76d88dc40ab247d1a894d15f30ffd56f-9e0c49ad10ddcf1bdd1662aaee3573890fae2e8f&ds=AVG&v=15.4.0.5&lang=en&pr=fr&d=2012-09-29%2009%3A30%3A50&sap=tr&q=how%20to%20determine%20spark%20advance%20with%20a%20performance%20cam

 

[Jethro Bodine]

I came home on my birthday and my wife had a bunch of friends over (one who was going to help me do the body work) and I went out to the garage and the car was gone! She actually had somebody come take my car for paint!

I think for my birthday my wife would probably have someone come and take my car...to the junk yard, lol.

 

[stovebolts]

I think for my birthday my wife would probably have someone come and take my car...to the junk yard, lol.

Hey, as long as you get to keep the scrap funds! ha ha!

Sooo.... this year for my birthday my wife got me a Holly 750 main body and a curve kit for the distributor. yeah, she's a keeper!

On a side note, it was soo funny! Last week we drove into town just the two of us for some ice cream and I pulled over and put her in the drivers seat. Now, you have to know that I've got double springs on the carb, so the accelerator is kinda hard to press. And with the manual valve body she just wasn't getting the ratchet shifter lol! And to top it off, the stall converter doesn't lock until 3000 rpm. Now, my speedometer isn't correct, but I bet we were doing a whole 40 mph in a 55... had a slew of cars behind us.. how embarassing lol! But it was fun!

 

[jasoncran]

I understand that. but the timing Is set at idle and then the ecm modulates it.

You know way more about this than I do, but does the ecm work with the O2 sensors in regard to timing? I know the 02 sensor starts to act as a temperature gauge at a particular point which can be used to gauge if the timing is too far advanced (running hot) or within range (timing correct). Where it gets tricky is running hot can also be correlated to running lean so is this where the second o2 sensor comes into play?

In simplistic terms, how does the ecm regulate perfect timing under all driving conditions and what sensors does it get it's information from? I'm kinda curious.

the 02 sensors only determine the amount of 02 in the exhaust. they tell the ecm if the fuel mix is rich or lean.nothing about heat. that is the thermistors job. that said, its called a KNOCK sensor. it is a piezoelectric sensor that generatates voltage when its moved by pressure or sound. the ecm sees this and then backs off the timing till it stops the knocking all modern cars have this per the obd2 act. Gm is the one who invented the concept of the knock sensor.

 

[stovebolts]

[MENTION=11841]jasoncran[/MENTION]

Thanks for the info! Good stuff.

I was reading a hot rod article that said after a certain point, the o2 sensor stopped reading o2 levels and started acting as a thermometer. Maybe this only applied to jimmy rigging a sensor on your own and reading it with a meter, not an ecm. The article said that as an 02 sensor, it would read the 02 levels to a certain point in line with it's voltage signal. Once you got out of that range, voltage output would increase as the car leaned out, thus more heat. Oh well, I"m not going to be welding an 02 sensor into my exhaust anytime soon anyway lol.

BTW, Jason, [MENTION=88699]Jethro Bodine[/MENTION] and [MENTION=1825]Lewis W[/MENTION] , I got my curve kit and 750 main body in the mail last night! Me and my son swapped out the parts last night and took her for a test spin! All I have to say is WOW!! Can't wait till I get her dialed in perfect!

So, usually when I pull off our road and onto the main road, I can stomp the gas to the floor and the car does a nice spin to which I do a quick counter steer, she bites and on down the road we go. Last night when I did this (Car was at 140 degrees) she about came around on me and I had to let my foot out of her or we would have done a 180 easily.

After warming her up, I mashed the gas, got a bit of hesitation and then man did she open up and throw us back! At about 4,000 rpm you could feel the cam open up and you could feel her pushing you back into the seat firmly until about 6200 rpm, but she was still pulling at 6800 rpm.

I did put the curve kit in which gives me a full 25 degrees of advance. Currently, I have no idea where my advance is set at. I desperately need a variable timing light and none of the local pawn shops have one. I also put in a different set of springs which gives me total advance about 3400 rpm.

I'm thinking Aug 30 should be the day to go to the track. That will give me time to get a drive shaft loop, a variable timing light and a jet kit for the carb. I hope with some tuning, I finally get her into the 12's.

In summary, with these two major modifications, she really came alive. Thanks Jethro for the pdf, it really helped me find a base to work from!

 

[Lewis]

How fast is your 0 to 60 ?

 

[jasoncran]

I forgot add that the ecm uses the camshaft and crankshift positions sensors to be able to know what cylinder is firing and can time each cylinder that way.

 

[stovebolts]

How fast is your 0 to 60 ?

I don't know how fast I was going at the 60 foot mark, but my time was pretty consistent at 2.12 seconds.
Fastest quarter mile was 91.92 @ 14:81
8th mile was 73.19 mph

After feeling the pull I got last night, I feel pretty confident in low 13's high 12's. The track doesn't lie so we'll find out soon.

I'm going to have some serious challenges getting the rear tires to stick with street tires after last nights upgrades. Before the upgrade I was spinning off the line so I think it's going to be about spin managment... in other words, how much spin is too much spin cause regardless, she's gonna spin.

BTW, I have custom front springs with QA1 shocks and custom drag springs (5 leaf) in the rear with old tired used shocks. (Yeah I know... don't say it). However, I do have a set of Competition Engineering Slide a Link's in the back. I've go them set to run on the street right now. Time to start dialing them in to see how much traction I can squeeze out of em.

This isn't a picture of my car, but it is a 1st gen Camaro with the same setup.

 

[Lewis]

You are on your way. now when you get the time clock how many secconds it takes to get from 0 to 60 that tells you a bunch about your power.

 

[stovebolts]

You are on your way. now when you get the time clock how many secconds it takes to get from 0 to 60 that tells you a bunch about your power.

Well, considering my Spedo isnt' correct I don't really have a way to find out how fast 0 to 60 takes.

I'm excited to go back to the track for some test and tune. I picked up my drive shaft loop today. Still need a timing light and some jets.

 

[Pizzaguy]

Having an Ultragauge on my Crossfire has been a real education. It shows any of over 50 parameters the ECM (PTCM in my car) is watching. I've learned a lot by watching it and reading about what Im seeing, but the questions you are asking are still over my head.

But what gets me, is the timing. One of the parameters I can see is the ignition timing. With the cam and crank position sensors telling the ECM where the crank is, and what speed it is turning, the ECM knows when to fire the plugs. By watching the knock sensor, the four O2 sensors in the exhaust, the coolant temp, the MAF, the fuel injectors and the throttle body position sensor, it knows all what's going on. What gets me is the ignition timing and how it changes. I KNEW that speed made it advance, but I did not know that throttle position also makes a big impact, too.

I see froma few degrees of advance to over 40 degrees at times! I had no idea it would vary that much, but with electronics, it can fire the plugs ANYTIME it wants to......

 

[Lewis]

Still need a timing light and some jets.

ebay' or amazon.com or rockauto.com

 

[stovebolts]

[MENTION=52402]Pizzaguy[/MENTION]

Yeah, all them electronics really make the engines run more efficiently which means more power. That's one of the reasons why a vette can push out 505 horsepower and still get 20 mpg.

I'm old school though looking for the best match to cover the broadest range.
[MENTION=1825]Lewis W[/MENTION]

I'd rather find one at a yard sale or pawn shop. Hopefully I'll find one soon.

 

[stovebolts]

Ok [MENTION=1825]Lewis W[/MENTION] , [MENTION=52402]Pizzaguy[/MENTION] and [MENTION=11841]jasoncran[/MENTION],

I got the new curve kit put in and 750 Main Body installed and did some minor tuning with the timing and played with the jets. I think I'm running a 78 for the primary jets and 86's for the secondary Jets. 76's and 84's I was still running just a tad lean. With this combination, I did run a 13.966 which isn't all that impressive, but it did drop almost a second off my previous ETA of 14.81. Also, I ran out of test and tune time so I didn't get to play with my timing. Currently my timing is at 37 degrees, and I would have liked to bump it to 39 degrees and maybe play with some lighter springs for the curve advance.

Launching off the line is now impossible without doing a controlled burnout even after dropping my tire pressure to 25psi. I've got old junky shocks in the back, so I'm thinking a new set of shocks is in order.

Not sure if I mentioned this before or not, but my heads are really working against me. I've got 215cc intake runners which are just way to big for a 355 cubic inch motor with 10.5:1 compression. This is a case where bigger isn't better. I'm being told that maybe I could try an RPM Dual Plane intake manifold which should increase my bottom end torque and may help. The only problem I see is the cam I have really makes some good power between 6,000 and 6,800 rpm. I played with my shift points and tried shifting at 6,000 and 6,500 rpm and both resulted in a lower ETA by just over a tenth of a second with the 6,000 rpm shifts closer to 2 tenths of a second slower eta.

Frustrating....

 

[Pizzaguy]

Not to get off topic, but take a look at THIS:

[video=youtube;ND4EA0dnAM8]http://www.youtube.com/watch?v=ND4EA0dnAM8[/video]

This guy is my hero! 305 cubic inches in two cylinders!
Finally, something AWESOME on YOUTUBE.