Im getting close to being done with my car and the road racing season is coming....

anyone have any timing / a/f ratio tips for tuning for road racing? figure 20 minute sessions on open track days. maybe hour sessions for small events, i doubt ill do any endurance 3 hour + events unless its one of the night ones next year.

sam

 

I would think that you would want to tune for low boost.

 

i plan on using a remote switch to boost lower in the turns and then higher in the straights. i will tune for both modes a lot.

i just need some tuning advice

 

 

I would use the remote switch as an overtake button (like they do in CART)....having a lot of power on the straights isn't necessarily a good thing.

 

Tune 14.0 a/f off boost, no real need to have 'excellent' mileage putting around.

and 12.0-12.2 a/f at max power, a little fat, but it'll run a long time like this.
no richer than 12.0 (you shouldn't need anymore fuel)

and don't run anymore timing that you 'need' to. On 18 psi I use just
20 deg total advance, again not MAX power, but safe on pump gas.
Comming down from 26 deg I only 'lost' 6 hp. A fair trade in my book.

If you run 100 octane race fuel, advance total timing to ~24-26 deg under high boost. Let the boost do your work for you, don't try to run timing on the edge.
More boost is safer than more timing.

These are conservative guidlines that I follow for street cars that belong to
other people that I NEVER know what they are going to do with, so I want the
motor to stay in one piece.

One more thing: a BIG oil cooler. so big that on the road you see the coolant
temp drop to the 'sandwich' plate temp....almost eliminating the need for a rad.


Just my opinion,
Jeffrey Atwood

 

thanks for the advice. sometimes ifeel like this forum is used to promote products people sell than it is to discussion technical things. seeing as people say tuning is the most important thing, and this is about tuning, im surprised at the low response.

anyway. 20 degrees at 18psi is quite a bit. id be mroe than happy with that. is that 20 degrees including the 16 base or no? im asuming no.

i am going to go for about 1 degree out per # and definitely look into the oil cooler.

thanks a ton again, i could touch on more of you what you said but im thankful for all the advice, it reafirms many of my thoughts

sam

 

The 20 deg refers to TOTAL ignition lead. 20 deg BTDC thats it...

Jeffrey Atwood

 

you cant just give a specific degree of timing retard, it also depends on what motor, compression ratio, the obvious fuel octane to name a few.

 

oh im well aware. just looking for other's findings in their setups as a baseline for what I am to find and do.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mase &raquo;</TD></TR><TR><TD CLASS="quote">you cant just give a specific degree of timing retard, it also depends on what motor, compression ratio, the obvious fuel octane to name a few. </TD></TR></TABLE>

The 'timing' number I gave is not timing retard... its TOTAL ignition advance...

you're right about the contribution of CR, octane, BUT take a look
at the timing curves of any (not just a Honda) engine and you'll see
that 20 deg isn't very aggressive.

experiment: set your timing to 20 deg everywhere and see how
'not' fast your car is off boost...

I dropped this number for tuning reference to show that for this particular
car I didn't need to run the timing on the ragged edge to make decent power.

Jeffrey Atwood

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jefnes &raquo;</TD></TR><TR><TD CLASS="quote">

The 'timing' number I gave is not timing retard... its TOTAL ignition advance...

you're right about the contribution of CR, octane, BUT take a look
at the timing curves of any (not just a Honda) engine and you'll see
that 20 deg isn't very aggressive.

experiment: set your timing to 20 deg everywhere and see how
'not' fast your car is off boost...

I dropped this number for tuning reference to show that for this particular
car I didn't need to run the timing on the ragged edge to make decent power.

Jeffrey Atwood</TD></TR></TABLE>


You should also be well aware that too little timing is not good either, as a matter of fact, 20 degrees of advance was too little in the prelude i tuned not too long ago, it would misfire.

So again, i reiterate, you can not just throw out universal timing numbers.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mase &raquo;</TD></TR><TR><TD CLASS="quote">
So again, i reiterate, you can not just throw out universal timing numbers. </TD></TR></TABLE>


Point taken, you are correct...

How was 'the misfiring on 20 deg' done.... just some tuning details, if you don't
mind. I have run less timing and have never gotten a misfire caused by it...
High egts, yes, but no misfire...

Just curious to 'see' the conditions it does occur.

Jeffrey Atwood

 

Mase, I am not going to go out and just throw some random numbers into my ignition / fuel map based on another's experiences. I simply was looking for experiences others had held. With these experiences I intend to more efficiently tune and find the best solution for my car, without wasting time making the same mistakes others have.