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Old 10-07-2002, 02:20 PM   #1
nmyeti
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Default Utec dyno plots and target A/F ratios and some tuning advice.

First off, I want to thank so many of you for adopting the UTEC as your preferred form of engine management. We've been very busy over the last few months getting everything tested and ready for the mass public release of the UTEC.

So far our results have been great, but I am not happy with only our results being great. I want to give away as much advice and data as I can to help you guys tune your cars to the level that we are seeing here in our shop.

I've heard a lot of people spouting "misinformation" about Air: fuel ratios, timing numbers, and just about everything else that has to do with tuning.

I decided that I would post some of the data from a few dyno sessions we've had in the last week or so to help give you guys an idea of what we tune to here in the shop. This is not meant to be a "we know best" post, but simply a way to show you what works for us.



This first dyno plot is of a car that we did this weekend. The three curves on the plot, from lowest peak HP to highest peak HP, are; 1. Pump gas map, 2. C16 map and 3. C16 + NX express Nitrous N-ter Cooler.

The basic setup on this car;
Turboxs STG4 kit with the following; PE1820 turbo, headers, Turboxs Hyperflow TMI, and NX Express Nitrous n-ter cooler.

As you can see from the chart the car made 317hp on pump gas, 342 on race gas, and 362.9hp with both race gas and the NX intercooler spray kit. This car made a whole lot of power!

I was very pleased with the way the torque curve ended up with the exception of the extra lag that the headers likely caused.

This is what I would call a "good tune"

Letís look at another dyno plot


In this dyno plot you see the A/F ratios and the torque curves of this weekend's tune.

The first thing I want you to note is how rich we must run the air/fuel ratio to keep detonation away at this power level on pump gas. As a whole the Air fuel chart shows from about 10.7:1 to just over 11:1. This of course was a custom tune and we would run an off the shelf kit a bit richer in the upper RPM so that we could keep the whole chart down around 10.7:1.

On C16 (116 motor octane, 117.5 research octane) we can run the car a good deal leaner but still not as "lean" as some of you might think. The extra advance we run on race gas lets us run a little leaner mixture since we don't need so much extra gas to cool the cylinder temps. This plot shows that on C16 we usually run between 11.5 and 11.7:1. This level of tune is about where Phil was running when he was at the Subaru shoot-out. It's still pretty rich, there is good gas in the tank, and we can run very nice advance numbers to get great power.

The next line on this chart is kind of instructive as to what charge density does to your A/F ratio. We started spraying the N2o over the intercooler at about 3500rpms. With no other changes in the tune the car leaned out to be between 11.9 and 12.4:1 gaining 20hp in the process. I don't expect that we could have ran it quite that lean without the extra charge cooling that the n2o provided while it was spraying over the intercooler. The end result was pretty outstanding.

What you should take away from these charts is that charge temp AND octane level will allow you to get away with air fuel ratios that would cause severe detonation on pump gas. I've heard a lot of people throw around the 12.5:1 number as ideal for turbo charged cars. This may or may not be the place where peak power can be made, but most of the time you can not even get close to that on pump gas and for the most part there is no need.

The next chart that I want to put up is one that shows a STG4TMI plot vs. a stock plot.



This was a custom tuned UTEC STG4TMI on pump gas. Note how small the changes are in overall air fuel ratio. This is another case where we are able to run a stage 4 car to a 10.7:1 air fuel ratio and make very nice power numbers. We could lean it out a bit more before detonation would set in, but the additional cooling that the extra fuel provides is well worth it when you know that the car your tuning might just hit 140mph one day.



This last plot is the same UTEC stg4tmi car vs. stock, but we are showing HP instead of A/F.

My guess is that this post has created as many questions as it has answered, but for now I at least want you guys to have this data. Iíll try to answer as many questions as possible.

-Nathan
www.turboxs.com
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Old 10-07-2002, 03:04 PM   #2
HndaTch627
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such a beautiful thing that is nice to see someone's hard work come out in such an incredible fashion....kick ass numbers and i can tell you that cars one hell of a ride

now he should have had you do a 100 octane map, guess i'll have to work with him on it, between jorge, me and him we'll make him something a lil more "affordable" for a race gas map for the street, but still, 312 WHP on pump gas is crapola your pants fast. before he came out to see you guys we went out(with the new inlet hose) and he bounced my head off the damn seat rest cause that car hit boost so much harder then i expected. good work guys, you never cease to amaze me.

jeremy

p.s.: i'd be curious too see the dyno chart and spool up time differences if i hadn't ported the flanges on the header. beucase the Stock outlet diameter remains on the turbo inlet flange but as requested that was opened to match the PE1820.
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Old 10-07-2002, 03:12 PM   #3
nmyeti
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Quote:
Originally posted by HndaTch627


now he should have had you do a 100 octane map, guess i'll have to work with him on it, between jorge, me and him we'll make him something a lil more "affordable" for a race gas map for the street, but still, 312 WHP on pump gas is crapola your pants fast. before he came out to see you guys we went out(with the new inlet hose) and he bounced my head off the damn seat rest cause that car hit boost so much harder then i expected. good work guys, you never cease to amaze me.

jeremy

Jeremy,
His car was sick. I really bet that he had a good long cry when he took it out after putting the pump gas back in it. The top end pull was so weird... There was no "hit" like an N2o car, but it just kept pushing you back harder and harder into your seat. Very cool... as a side note the 1820 lags worse than my GT35R. Thought i might tease people a little bit with that

-Nathan
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Old 10-07-2002, 03:15 PM   #4
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How much do you guys charge to tune the car per hour
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Old 10-07-2002, 03:20 PM   #5
nmyeti
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Quote:
Originally posted by slammedWRX
How much do you guys charge to tune the car per hour
$150 an hour with a $50 setup fee for the dyno.

-Nathan
www.turboxs.com
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Old 10-07-2002, 03:49 PM   #6
HndaTch627
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Quote:
Originally posted by nmyeti
There was no "hit" like an N2o car, but it just kept pushing you back harder and harder into your seat. Very cool
Yeah well i've already spoken to him about doing it and show him the idea of the system I think would be perfect for what he needs. But he's gonna need a clutch and gearset soon

Jeremy
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Old 10-07-2002, 03:51 PM   #7
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how long does it normally take to tune
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Old 10-07-2002, 03:58 PM   #8
nmyeti
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Quote:
Originally posted by slammedWRX
how long does it normally take to tune

We spent 4.5 hours on the tune that is the first set of dyno plots.

We spent about 2.5 or so on the second set of plots.

-Nathan
www.turboxs.com
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Old 10-07-2002, 04:17 PM   #9
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good stuff nathan! amazing how rich the stock car runs. What id really like to see is a basically stock car with a custom tuned UTEC overlayed to that completely stock car (simple things like an uppipe would be fine, but I really would like to see as close to stock as possible). If you cant provide that, maybe a custom tuned stage 2 on pump gas. Thanks!
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Old 10-07-2002, 04:24 PM   #10
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Just wondering what sort of AFR you guys try to hit when tuning for pump gas. I just got a WB02 sensor but don't have a bung to install it in yet so I don't know how rich the STi runs in stock form but the nice black tailpipe suggests it runs pretty rich.

From what I've seen watch the USDM WRX in stock form it seems to be as pig rich as 10:1. I've seen tuners lean them out as far as 12.8:1. I'm wondering what your thougths are on this.

-Michael
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Old 10-07-2002, 04:27 PM   #11
nmyeti
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Quote:
Originally posted by d00f
Just wondering what sort of AFR you guys try to hit when tuning for pump gas. I just got a WB02 sensor but don't have a bung to install it in yet so I don't know how rich the STi runs in stock form but the nice black tailpipe suggests it runs pretty rich.

From what I've seen watch the USDM WRX in stock form it seems to be as pig rich as 10:1. I've seen tuners lean them out as far as 12.8:1. I'm wondering what your thougths are on this.

-Michael
Michael,
Read the post and look at the charts... your question what the whole point of the post. I posted several A/F charts that should be used as an answer of what we shoot for when tuning a WRX on pump gas.

12.8:1 is really lean for any of the fuels that i've used.

-Nathan
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Old 10-07-2002, 04:56 PM   #12
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12.8 was the leanest I've ever seen with most of them targeting about 12.0. This is all assuming my lambda to AFR conversions are correct as the european tuners I've met and talked to speak only of lambda and bar whereas I can only think in AFR and PSI.

It just strikes me as being really rich when if I read this correctly, your really tuned and leaner than normal is running 10.7:1.

I'm wondering what sort of scientific approach was used to determine the optimal ratio. What was the ignition advance around peak torque? What method was used to find the optimal advance?

-Michael
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Old 10-07-2002, 05:02 PM   #13
nmyeti
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Quote:
Originally posted by d00f
12.8 was the leanest I've ever seen with most of them targeting about 12.0. This is all assuming my lambda to AFR conversions are correct as the european tuners I've met and talked to speak only of lambda and bar whereas I can only think in AFR and PSI.

It just strikes me as being really rich when if I read this correctly, your really tuned and leaner than normal is running 10.7:1.

I'm wondering what sort of scientific approach was used to determine the optimal ratio. What was the ignition advance around peak torque? What method was used to find the optimal advance?

-Michael
Michael,
I'll post the maps from this tune soon. We strapped the car to the dyno and started working the advance up to ranges we were comfortable with. Each degree of advance increases torque up to a point where you gain almost nothing from extra advance.

10.7:1 is a good target for pump gas. It's rich enough to keep EGTs down, and also rich enough to keep your motor away from the detonation zone if you get a bad tank of gas.

-Nathan
www.turboxs.com
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Old 10-07-2002, 05:10 PM   #14
nmyeti
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1820 pump gas map from this tune


1820 C16 race gas map

Ok now you guys have more than enough data to have a look at what we are doing. These are the maps we used to get the results from the first set of dyno plots.


I am not suggesting anyone use these as they are a custom tune. The race gas map MUST BE USE WITH C16 no other race gas comes close.


-Nathan
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Old 10-07-2002, 05:21 PM   #15
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This is great stuff, but it doesn't help the average "road tuner". I don't have a wideband o2 sensor - in fact, all I have is the A/F ratio that the UTEC has on it. And, I'm using water injection.

Any idea how I can get my A/F ratios better? I'm seeing some VERY strange stuff in my data logs - RPMS dropping to zero, A/F ratios going from "rich" to 21 or 22 (car wouldn't even be able to run yet its still rich) things like that. Is there any way to get the actual voltage coming off of the sensor? Or can I throw those two dip switches to use the rear o2 sensor, and it will report to me voltage via the rear?

I know this all seems very strange, and I'm pretty perplexed myself. I'm basically tuning via EGTs and knock (which I can't see really, other than when I actually get it - any chance of making the knockcount number visable?), which is hit and miss and potentially dangerous at best.
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Old 10-07-2002, 05:29 PM   #16
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What would the effect have been with less advance and less fuel? Also, your pump gas is what (north american system) octane?

I used to have a Tec-II in my NA EJ25 and I found that there was a good plateau where leaning it out and retarding the ignition resulted in approx the same amount of power. Yes, NA is a different ballgame but from what I'm told the same principles apply in a turbo application, just that you'd never run a turbo at 13.2:1 under boost.

I have a stock STi ECU and no adjustments yet, but I've run 91 octane with a very noticeable drop in power. At stock boost Sunoco Ultra 94 runs really well. Has never knocked or pinged on me and I've cranked the boost as high as 20 PSI (stock is 15.5 and the boost cut is at 22).

The WRX I sat in was running 10.6 in stock form. The unichip tuner leaned it out to about 11.6 as well as advancing the ignition by a few degrees. The power increase was very noticeable and the more he leaned it out the better it went. All this and the EGTs were staying quite low.

Is it possible that this large discrepancy is coming from the specific mods on the car you were tuning where for some odd reason it likes to be run really rich?

It's possible that my tired recollection doesn't have the numbers right but it just strikes me as really rich...

-Michael
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Old 10-07-2002, 05:42 PM   #17
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The guy with the 1820 should try some ported and wrapped stock headers - and a port job on the 1820 - i bet he'd get some spool up with that


hey nathan - how is the gt35 working - - did you get it running yet ?
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Old 10-07-2002, 05:46 PM   #18
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Quote:
Originally posted by d00f
What would the effect have been with less advance and less fuel? Also, your pump gas is what (north american system) octane?
93 octane; Less advance and less fuel = higher EGTs in the upper RPM range. For reference the stock ECU wants to run as much as 34-36 degrees at redline on C16.

Quote:
Originally posted by d00f
The WRX I sat in was running 10.6 in stock form. The unichip tuner leaned it out to about 11.6 as well as advancing the ignition by a few degrees. The power increase was very noticeable and the more he leaned it out the better it went. All this and the EGTs were staying quite low.
Just wondering did the tuner check the detonation level with a microphone on the block and a head set? I'd be surprised if you were not getting detonation at that level that was too slight to hear over the engine noise in the dyno room.

The advance helps keep the EGTs cool, so you can advance and lean the car out if you have enough octane to support it in your fuel, but frankly pump fuel in most of the US does not have enough to keep the small detonation away from your motor at the A/F level you're quoting. It's even worse when you also know that the car is going to lean out a bit on the road because of additional air flow over the intercooler.


Quote:
Originally posted by d00f
Is it possible that this large discrepancy is coming from the specific mods on the car you were tuning where for some odd reason it likes to be run really rich?

It's possible that my tired recollection doesn't have the numbers right but it just strikes me as really rich...

-Michael
We run a stage2 car in the 10.5 to 10.7:1 range. We run them rich to keep our customers from running into issues when they road-race the car or fill up with less than perfect pump fuel. We also know that there are customers that will up the boost and take the car on very long high speed runs. I want to know for sure there is enough fuel in the system to keep detonation and EGTs under control. We only lean the car out when we make a "race gas" map.


-Nathan
www.turboxs.com
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Old 10-07-2002, 05:50 PM   #19
nmyeti
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Originally posted by alfriedesq
hey nathan - how is the gt35 working - - did you get it running yet ?
Al,
It is a very nice turbo; wicked fast spool with the 2.5L block. Lots of grunt down low and plenty of top end pull. At 14psi (waste-gate boost) it will lay down a whole lot of rubber in 1st if I try to come out of the hole at anything over 3500-4000rpms. In most cases the waste-gate is open before I am fully off the clutch.

In short I love this combo. With any luck Iíll have it on the dyno this week since I am just about ready to turn up the boost.

I think youíre right about the stock headers. I told this guy the exact same thing.

-Nathan
www.turboxs.com
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Old 10-07-2002, 06:03 PM   #20
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Quote:
Originally posted by nmyeti
1820 pump gas map from this tune


1820 C16 race gas map

Ok now you guys have more than enough data to have a look at what we are doing. These are the maps we used to get the results from the first set of dyno plots.


I am not suggesting anyone use these as they are a custom tune. The race gas map MUST BE USE WITH C16 no other race gas comes close.


-Nathan

For those of us using the various maps for reference, note that the PE1820 93 octane map is labeled "VF30", not PE1820.

SJ
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Old 10-07-2002, 06:11 PM   #21
nmyeti
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It started life as a VF30 base map and we built it from there. I need to edit the map to show the new "name"

-Nathan
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Old 10-07-2002, 06:51 PM   #22
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Nathan... any ideas on my question I asked?
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Old 10-07-2002, 07:00 PM   #23
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Quote:
Originally posted by nmyeti
[b]
Just wondering did the tuner check the detonation level with a microphone on the block and a head set? I'd be surprised if you were not getting detonation at that level that was too slight to hear over the engine noise in the dyno room.

The advance helps keep the EGTs cool, so you can advance and lean the car out if you have enough octane to support it in your fuel, but frankly pump fuel in most of the US does not have enough to keep the small detonation away from your motor at the A/F level you're quoting. It's even worse when you also know that the car is going to lean out a bit on the road because of additional air flow over the intercooler.
Actually we were out driving. He'd already set the timing before taking me for a spin. I believe he uses a setup with 2 knock sensors, each going to 1 channel in a set of stereo headphones.

If I'm hearing detonation with my bare ears then it's very severe! As in blow your engine severe forged pistons or not. Personally I just have a small audio preamp on the factory knock sensor. That goes into a set of headphones. Used that with good success with the tec-II.

-Michael
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Old 10-07-2002, 07:33 PM   #24
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Good stuff:-). Thanks Nathan as usual.

Shawn
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Old 10-07-2002, 08:09 PM   #25
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Quote:
Originally posted by DarthChicken
This is great stuff, but it doesn't help the average "road tuner". I don't have a wideband o2 sensor - in fact, all I have is the A/F ratio that the UTEC has on it. And, I'm using water injection.

Any idea how I can get my A/F ratios better? I'm seeing some VERY strange stuff in my data logs - RPMS dropping to zero, A/F ratios going from "rich" to 21 or 22 (car wouldn't even be able to run yet its still rich) things like that. Is there any way to get the actual voltage coming off of the sensor? Or can I throw those two dip switches to use the rear o2 sensor, and it will report to me voltage via the rear?

I know this all seems very strange, and I'm pretty perplexed myself. I'm basically tuning via EGTs and knock (which I can't see really, other than when I actually get it - any chance of making the knockcount number visable?), which is hit and miss and potentially dangerous at best.
I second DarthChicken's questions. How does an average road tuner get a/f ratios better? Is there a good cheap wbO2 that we can buy? Or is this one of the goodies turboxs is working on?
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