Some Basic tuning rules with Boost

[Ted Jannetty]

I was reading the post on 12 lbs. boost on pump gas, and figured I would start a new thread so it doesn't get lost.

I have been building and tuning engines with superchargers, turbos, nitrous and the like for 25 years, here are a couple of rules that I use as a base line.

Say the engine is designed to run on 87 octane fuel Like ours.
For every pound of boost you should go up 1 octane and preferably out of a sealed container like race fuel, I don't recommend playing Chemist.

I use 100 octane unleaded Sunoco race fuel, I should be able to run 13 psi boost as long as my A/F are kept in a safe region.

This doesn't mean you can run 23 psi boost on 110 it gets a lot deeper but I won't get into it now

I shoot for 11.8:1 to 12.0:1 A/F Under boost with a taper.
For example; full throttle with no boost should be 13.0:1, 5 Psi boost should be 12.5:1 and 10 Psi and above should be no leaner than 12.0:1

Leaner A/F will burn pistons, Rings, valves, and create excessive heat that leads to detonation that will blow head gaskets, break pistons and bend connecting rods.

Also very important, depending on the engine and the fuel, at about 7 psi boost, I start pulling timing at a rate of about 1 degree per pound of boost as a starting point, this has the same affect as lowering compression again, to a point.

This info is only good to about 14-15 psi boost above that compression should be reduced.

Also note that the factory leaves a little room for safety when stock.
Example; If the engine makes max power at X timing they usually will take away a few degrees timing for reliability incase you get bad fuel.

This is why we can take our naturally asparated engine add a turbo and safely run 7-8 psi on pump gas of 93 octane.

It is all about balancing clyinder pressure and fuel combination so that peak cylinder pressure occures at about 15 degress AFTER top dead center.

I also should add that Cooling system upgrades are a MUST anytime you make more power than Stock or Engine Failure Will Result.

This information is to be used at your own risk I take no responsibility to the outcome due to variables beyond my control, it's intent is for dicussion purposes only.

 

[slymax]

Do you know what effect putting a head gasket shim in has to that? I ask that because when running 12lbs of boost on pump(91 octane) I am pretty sure everyone that is doing it has the head gasket shim.

 

[Ted Jannetty]

Lowering compression reduces thermal dynamic loading therefore reducing the possibility of Detonation on a given fuel.

Altitude plays a big roll in the calculations.

At high altitude you can run more timing and more boost than at sea level on the same fuel.

 

[FastAction]

Ted,

So I should be safe, I am running 15 lbs boost, have three yammi headgasgets stacked and using straight c-12. Nothing has blown up yet.

Thanks for any input

 

[Ted Jannetty]

All I can tell you is Read Your Plugs they will tell you if your OK or not.

 

[FastAction]

What the hell is a plug?

 

[TurboKeith]

Have you tried to get to the plugs on an Apex? I'm guessing that Yamaha was figuring that since you don't need to change them for several thousand miles, you must not ever need to look at them.

 

[Ted Jannetty]

Yeah I know what you mean, I got my new GT this week 433 miles so far and I have never had the hood off yet.

By the Way, My Warrior fly's, 10 sled lengths on the fasted race sled on the lake this week, it was an 1108 Hooper Race sled, that has ruled
Back lake for the last 3 years.

I am pretty Thrilled with the whole package.

Thought you guys would like to know

 

[rxrider]

Ted - Thank you for sharing your knowledge on turbo engines. I'm running 3 yamaha head gaskets and Wiseco 10:1 pistons, still only running 10 lbs on 93 octane pump, guess I'm pretty safe. I want to install a wbo2 before I start raising boost. What wbo2 sensor and gauge fit with the RX-1 MCX rear mount, and where to get it?

 

[Ted Jannetty]

Ted - Thank you for sharing your knowledge on turbo engines. I'm running 3 yamaha head gaskets and Wiseco 10:1 pistons, still only running 10 lbs on 93 octane pump, guess I'm pretty safe. I want to install a wbo2 before I start raising boost. What wbo2 sensor and gauge fit with the RX-1 MCX rear mount, and where to get it?

I can provide you with the same one I have on my sled it is Innovate XD1 stand alone Wide Band O2 gauge

Seen here,
http://www.innovatemotorsports.com/xcar ... hp?cat=252

I sell them for the same price.

 

[rxrider]

Thanks Ted

Is this the kit you have? http://www.innovatemotorsports.com/xcart/customer/product.php?productid=16167&cat=252&page=1 - How is it watching in broad daylight? BTW it has nice looks, it matches my black and blue theme on my sled. I will get back to you when I'm ready to buy one. What does the leds on the outer edge do? One blue is lit in the advertising.

rxrider

 

[Travis Moore]

I'd never buy a system that does not let you use a NTK sensor. With a NTK sensor, you can use leaded fuel.

 

[Ted Jannetty]

I have this one http://www.innovatemotorsports.com/xcar ... 252&page=1

 

[Ted Jannetty]

This calculator agrees with what I said above thanks to Slacker for creating it.

 

[RunninRX1]

I'd never buy a system that does not let you use a NTK sensor. With a NTK sensor, you can use leaded fuel.

<cough>bullshit<cough>