IM talking with a local shop about doing it. I havent gotten a price from them yet. Just wandering if IM getting a good price or not.
And is this the best way to tune it?


Mike

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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

[This message has been edited by MikeH (edited October 02, 2000).]

 

not the best way to tune it, it doesnt account for vehicle weight, wind resistance and any other variables you encounter when racing at a dragstrip. I hear it can be an aid but not the be all and end all to tuning

 

Contrary to Pablo's response (hi Pablo!), my opinion is that the dyno is the best way to tune the car. But ONLY if the shop in question uses a wide-band O2 sensor, and has a scan tool to monitor spark knock. Using those two tools, the chip can be made to produce optimum power at a safe air/fuel ratio, and optimize the spark timing without getting any detonation.

Nick

 

The dyno is perfect for nailing down the WOT curve and also for standard driving conditions IF AN ONLY IF they have a wide band O2. However, in terms of other forms of driving ... such as driving up steep inclindes, coasting, etc. the dyno isn't really going to help.

Tim

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TRAXION's 1990 IROC-Z
Best Time = 12.587 @ 107.97mph (1.710 60ftr) on the long runner setup.
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels. Stock Wheels. No Weight Reduction.
Gunning for NA 11's with the MiniRam II and Hooker LT Headers.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

Well in my opinion (Hey nick! lol) the amount of load on the engine is very important especially when speaking of spark advance and such. For example, old school drag racers found that when they retarded their timing some (total advance) they would slow down their 1/8th mile times, but were suprised to see that the second half of the quarter times improve significantly. Later they rigged up cables to manually pull back the timing the faster they went in the quarter.. why? Wind resistance obviously and probably a few other factors aswell. Would that have shown up on a dyno? Lets also not forget that in the same fashion, fuel might play a part. You can dyno a car on the rear wheels, and whether the car is 10000 pounds or 2000 pounds you are going to tune it exactly the same if it were the same engine combination. Extreme case, but it illustrates how a dyno does not take vehicle weight into consideration and can have some pretty obvious consequences. On a dyno factors like these dont come into play, and not to detract from the fact that they ARE helpful, the end all is track time. Not even a WB o2 is an end all, no engine wants a constant AFR all the way up the rpm band, go check out www.edelbrock.com and there is a chart in their carb section of the airfuel ratio of a certain motor as an example. Not even close to flat.
Like i said, dont get me wrong, dynos are great, but if you tune your car to just to run good on a dyno then thats the best place it will run, on a dyno

 

Hmmm, seems like an interesting discussion is brewing....or dare I say *debate*?

Pablo, since you feel that track tuning is better than dyno tuning, let me ask you this: How often is your engine between 1000-3000rpm when you're going down the 1/4 mile?

My guess is that it's there only during the launch in 1st gear. That's not much data to collect in order to tune that RPM range. If you're gonna through the trouble of custom tuning your chip, I'd think you want to be able to extract maximum power from the entire RPM curve, not just the upper RPMs. I really don't see how you're going to tune those lower RPMs at the track. With a dyno, you can tune the entire RPM range that the engine encounters.

My next point deals with consistency and accuracy. On a dyno, you don't have to worry about off the line traction, shift points, how long a shift takes, headwind, etc. The dyno is a more controlled environment. This allows minute changes to be seen. As an example, you can see, and fix, a 5hp dip at 4800rpm on the dyno. I highly doubt you'll be able to even know that a power dip like that occurs when tuning at the track.

Another point you made was that the dyno cannot load the engine like reality can (ie, accelerating the actual vehicle vs. accelerating a 1000lb steel drum). While you're right (even though you CAN vary the load on the engine with a rear wheel dyno), it's a moot point. Let's take a typical GM speed density application as an example. The main maps you're gonna modify are the spark table, the fuel/VE table(s), and the WOT A/F ratio tables.

As you know, the VE table has manifold vacuum as one of its axis. When under WOT, the engine operates at the column of least vacuum (aka, most pressure, near atmospheric). The engine will be at that part of the map no matter what gear it's in (1st, 2nd, 3rd, 4th, etc.). How do you propose on extracting maximum performance for each gear (when you're track tuning) if each gear uses the same table locations? How are you gonna differentiate between the gears? How did varying the engine load by driving it on the track help with tuning it?

As far as the wide-band oxygen sensor is concerned, I think you misunderstood my point. I never said that you should tune for the same air-fuel ratio across the RPM curve (if I did, then I didn't mean to). You use the WBO2 to indicate whether or not you're still in a safe ratio (to maintain reliability).

As an example, you may find that you make maximum torque down low with and air/fuel ratio of 12:1. But as the revs climb, the engine wants less fuel. You may reach maximum power with an air/fuel ratio of 13.5:1. But at an a/f ratio of 13.0:1, you're only down 3hp at the peak. Personally, I'd prefer to run the 13:1 mixture (as it's safer) and give up 3hp.

You use the WBO2 to show you where you're at with your tuning, and how close to the edge you are. It's a tool to help show what state your engine is running at. It's not meant to set the operation to one A/F ratio everywhere (unless that's what you want).

Now, you better agree with me or I'll stop showing you how to read through the '747 code

Nick

 

Hehe Good points, and I agree with you on many of them

First, I do not discount a dyno or a WB o2 as a tuning AID. THey are excellent tuning aids BUT they do not take the work out of tuning. I think a dyno would be a great place to first get a base calibration that does great on the dyno, and then build upon that at the track.

You said :
"Another point you made was that the dyno cannot load the engine like reality can (ie, accelerating the actual vehicle
vs. accelerating a 1000lb steel drum). While you're right (even though you CAN vary the load on the engine with a
rear wheel dyno), it's a moot point."

Correct, as far as i know, only a clayton dyno or a mustang dyno can do this and i feel that it will give misleading results anyways since load always varies

you then said :
"s you know, the VE table has manifold vacuum as one of its axis. When under WOT, the engine operates at the
column of least vacuum (aka, most pressure, near atmospheric). The engine will be at that part of the map no
matter what gear it's in (1st, 2nd, 3rd, 4th, etc.). How do you propose on extracting maximum performance for each
gear (when you're track tuning) if each gear uses the same table locations? How are you gonna differentiate
between the gears? How did varying the engine load by driving it on the track help with tuning it?"

To answer your final question which covers the others, is that that is the whole point of tuning at the track, to find the best balance between various settings that will yield the greatest average power in say the four different load levels a particular rpm faces (in a 5 speed car of course) This of course is shown in the combined result of ET and trap speed

as for the WB O2, i agree with you! its AWESOME (and im gonna be your best friend when you get yours )
BUT, once you get your O2s where you want them to be do you just settle? or do you go to the track and then make some adjustments to see what makes a difference or not? Course you do because like you said, the O2 is a variable when it comes to which delivers the most power

the question was WHAT way is the best way to tune, and obviously just a dyno and WB o2 is not the answer, it can be a combination of those things AND track time, but you cant tune a car with only a dyno and WB o2 whereas you CAN tune a car with just track time (Don garlits and the like did it since before we were born, just more of a PITA)


Pablo

 

Geez ... isn't that what I said but in not so many words?

Tim

------------------
TRAXION's 1990 IROC-Z
Best Time = 12.587 @ 107.97mph (1.710 60ftr) on the long runner setup.
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels. Stock Wheels. No Weight Reduction.
Gunning for NA 11's with the MiniRam II and Hooker LT Headers.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

Thanks for all the information guys! The guy just bought the stuff to burn proms. He also just installed a new Dynojet air/fuel module. I still havent gotten a price to do it. He does charge 105.00 an hour for tuning. IM kinda nervous about him tuning it if he is new to it.

Mike

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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

 

But how much does it cost?
I talked to ED Wright at Fast Chips in Tulsa.
To burn a new chip and dyno tune it he wants
$500 and is booked till january 20, 2001.
I have heard good things about him on this board and he must be good to be booked that far in advance. Just some info from an old carb guy ...bob

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91 camaro RS convert
t-5
open element air cleaner
TBI spacer
Flowmaster muffler