Finished!! Forged piston block, Custom valve head (flowbenched)

[Ondonti]

I did a 4th gear datalog tonight. Had to update the Zeitronix software because my wideband controller got updated when it was fixed.

I think its a great tune right now but the car is too scary for me to play on even an empty road like that in 4th gear.
120mph is not something I like doing, especially when I know I have to hit the brakes because its not the freeway.

[kreel]

Do you have the stock drums in the rear? I know I'd be scared to have to slam on the brakes at 120mph with those in the back

[Ondonti]

The car is really light.

I have never "slammed" on the brakes before so I really have no idea how the car would react. Pretty much I am chicken :P

Also, with almost no weight in the rear of the car, it is not a good idea to upgrade rear brakes.

[Reaper1]

^^I agree. Not only that, but it would do no good since about 70%(or more in some cases) of the braking is done in the front anyways on a normal car. The rear disc set-up is also heavier than the rear drums....hence why I'm not changing them out on Charlotte! Discs look cooler, but they aren't needed!

[Shadow24V]

+1, i thought about the SLH upgrades, but even in a stock weight P-body, i can still lock up the tires if i really tried. i can get my car to stop pretty darn well as is (no abs is a good thing IMO ) so im probably going to forgo the SLH upgrades and stay stock unless needed.

Brent, your not as chicken as me, ive only had my car up to 105 and that was on the highway the other day! but i know what you mean, i wouldn't do 100+ on the roads near my house ether.

[kreel]

Ahh, ok. Makes sense.

Drums are really lighter, eh? I've heard that before...but looking at the rear discs on my CSX the difference can't be that much

[Shadow24V]

discs are not self energizing like drums too

[speeduphoria]

Quote:

Originally Posted by Shadow24V +1, i thought about the SLH upgrades, but even in a stock weight P-body, i can still lock up the tires if i really tried.

If you lock them up you need better tires as that is really what stops you

[Shadow24V]

yeah, i figured. but thats also SLAMMING on the brakes instead of a controlled hard stop.

this summer is maybe some new rims and better summer tires. All-seasons arnt the best for traction...

[c2xejk]

Quote:

Originally Posted by Ondonti Well I would have to figure out the basics of that kind of tuning before I did the boost per gear and stuff like that. One thing about the 7.0:1 compression is that I can throw tons of timing at it. I have the base timing WAY advanced and dont actually know what it is right now. Probably 20 degrees. Thats how I can make the 7:1 motor act more like a 9:1 motor. And I could easily run it on 85 octane too or really really lean and it wont complain. I just wont do that out of a desire to have good turbo habits.

I am confused by this. Normally when you boost, you retard spark timing.

Are you saying that you are making more power with the timing advanced? Or just that you can advance the timing a rediculous amount without knocking? (which a stock 3L can do.)

[speeduphoria]

Heres a good read

Tech Page

[87turbodance]

Good read and some interesting info at the end about water injection. One really sweet thing of MS is that you can have a whole map devoted to water injection based on RPM and manifold pressure. Get 6 stainless injectors and make up a stainless "fuel rail" for them and you can precisely inject water or water/meth. This has always been my plan. A setup like that on your 3.0 would make for a stupid fast car on pump gas - even more stupid fast then it already is!

[Ondonti]

Quote:

Originally Posted by c2xejk I am confused by this. Normally when you boost, you retard spark timing. Are you saying that you are making more power with the timing advanced? Or just that you can advance the timing a rediculous amount without knocking? (which a stock 3L can do.)

When you have low compression you lose some power but low compression can gain back the power by advancing the timing because the lower compression can use a lot more ignition advance then higher compression motor. So with only 6 pounds of boost and 7:1 compression, I can run tons of timing, which also makes the car more responsive out of boost.

If I cranked the boost way up, then I would want to be more conservative on the timing. As it is, I really dont think the car needs chemical intercooling (water or meth) until well after 450whp, but if you add chemical intercooling you can run more timing at the same higher boost level and make more power. I have decided to either run e85 or 100% meth in my alky system so it will not only allow more timing but make more power simply because of the alky fuel making more power based on the a/f ratios you need to run it at and how much BTU's it creates when burning (meth = 20% more hp then gasoline at stoic and e85 should make 7-8% more).
e85 isnt as effective at intercooling as meth or water but it will add fuel and I dont need that much extra octane.

[bansheenut420]

You going to come up for the test and tunes?

[c2xejk]

Quote:

Originally Posted by Ondonti When you have low compression you lose some power but low compression can gain back the power by advancing the timing because the lower compression can use a lot more ignition advance then higher compression motor. So with only 6 pounds of boost and 7:1 compression, I can run tons of timing, which also makes the car more responsive out of boost.

That is not quite right. You can/need to run more advance because the combustion chamber is bigger and it takes longer for the flame front to cover the whole chamber.

When you advance the timing you are lighting the mixture off before Top-Dead Center (TDC.) So the initial burning A/F mixture is actually trying to push the crankshaft _backward_.

In an ideal world you would want to light the mixture after TDC so none of the fuel is used to push the crankshaft backwards. There is actually an angle where you want to put the peak cylinder pressure (it based on engine geometry...)

If you look at some of the gains made by racers it has been by using a more efficient combustion chamber and being able to make peak-hp with _less_ spark advance.

One of these days Mike or I need to do a write-up about spark hooks. But the bottom line is as you increase spark advance, hp will go up, peak and then go down. The exact shape and position of the spark hook is dependent on the complete engine configuration.

As we were tuning the spark advance on my van we could see this effect with successive dyne pulls. We advanced the timing (small changes) until peak hp went down, then went half way in between and found the peak. Advancing the timing any further would have only hurt hp.