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Old 01-24-2005, 01:45 PM   #1
SloRice
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Default Increasing Spool up

Due to my job, I talk with quite a few different customers about cars and tuning. Well Iíve been speaking with one of my customers about tuning turbocharged vehicles. He mainly works on turbocharged Mustangs.

The normal school of thought for increasing spool up is to lean out the A/F in the lower RPMís so that EGTís rise which creates a very high exhaust gas velocity. But after talking with this guy, he put a bug in my ear as far as this subject is concerned.

He says that instead of leaning it out, he richens it upÖ.a lot! While this does make your EGTís lower and exhaust gas velocity slower, it allows unburned fuel to go into the exhaust system which makes the exhaust gas much denser that if the fuel was completely burned off. He said heís seen spool up differences of 1000 RPM between the two styles of tuning. And itís not as hard on the motor because you arenít running dangerously lean in the lower RPMís. Is this the same school of thought as anti-lag?

The reason I put it in this forum is first off, I have one and I wanted to see if this style of tuning had any merit with the EJ257 motor. Also since lately companies are putting large turbos on the STI, it may open up doors to even larger turbos and more HP.

TIA,
Tim
Sales Engineer
Mustang Dynamometer
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Old 01-24-2005, 01:49 PM   #2
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I'm not necessarily qualified to answer, but I've heard tuners that I respect say that richening does spool the turbo faster, but it also makes less power while doing so. So, if you're only goal is to spool faster, yeah this works. But if you actually want to make more power and have a more responsive engine, it doesn't make sense.
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Old 01-24-2005, 02:02 PM   #3
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What about bore wash in rich conditions? These cars already run a bit rich in stock form. Just what RPM range and engine load would this approach be appropriate?
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Old 01-24-2005, 03:58 PM   #4
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I've also heard of (and seen) people running very low timing (in the +5-9 range) to spool the turbo too. I would be happier doing it with timing than by a super rich afr.
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Old 01-24-2005, 04:27 PM   #5
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Default haa ha...

interesting...

we went through this last week while tuning the stil....

with the race cars, we use antilag systems to keep the turbo spooled when u are off throttle, or when u want to use a higher gear, but are below the normal peak power range...

normally we mechanicall crack the throttle, and retard the timing and add fuel...

i have the same discussion with the person whose shop we were using to dyno.... he said "i like to run lean down low to increase spool up..."...

i like to do the opposite....mainly people tend to add fueling certain places when they should just retard the timing...that's the biggest thing ive found with the maps ive seen.....

we in turn would retard the timing..and add a bit of fuel to create the condition u spoke of.... we actually made power power about 1200 rpm sooner on the sti with jsut our i/c and some tuning... also jumped 47whp and 62wheel torque on pump gas....

anyway...funny u brought that up...but like i said...guys when u are doing ur tuning....try retarding the timing when u get knock or afr problems instead of always throwing fuel at it....

adding fuel is thought too cool temps, when actually it causes the burn to be longer/later .... which can be achieved with timing retardation...

anyway, my two cents, im sure people will say im wrong...

but...i have been actively involved in engine mapping in more than a few race cars..

cb
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Old 01-24-2005, 04:30 PM   #6
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Default oh yeah

and tim...

im interested in a mustang dyno, can u pm or email me?

chad@chadblock.com

slamdvw on aim/aol

cb
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Old 01-24-2005, 04:31 PM   #7
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It's not "anti-lag" tuning, also called "bang-bang" for the sound it makes. The fuel is ignited late and is still burning as it exits the cylinder. Yes this dumps an enormous amount of heat into the exhaust and extremely high EGTs, but it also fries your exhaust valves, exhaust system, and turbo. Unless you are rebuilding your valvetrain and exhaust regularly (that is replacing them) this is just not a viable option on most cars.

I've never heard of tuning extra rich with the thought that the density of the vaporized fuel is used to turn the turbine. Having super hot flammable gas traveling through your exhaust system does not sound smart. It certainly violates Corky's thoughts on temp drop across the turbine being the main energy transfer to the turbo shaft. I can see the leverage advantage to a denser exhaust, but I don't see the speed advantage, and it's the speed you need.
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Old 01-24-2005, 04:36 PM   #8
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Default heee hee

oh no!! he brought up maximum boost...

hee he..... i love bell, but alot of his theories have seen been updated/changed by other reputable engine building/development companies...

you are correct in what u say....but not all anti-lag systems are sooo aggressive to get the bang bang effect.....

it does create a lot of heat on the hot side of the motor, but u can use it to a degree to get spool up....... antilag is mainly upon shifting with a sequential (another reason they dont run bov's on most turbocharged race cars) ....and low speed applications....

i have driven on a few different anti-lag programs....

but your info is correct....in the tuning world...like anything else, used in moderation...it works...

cb
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Old 01-24-2005, 04:38 PM   #9
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Quote:
Originally Posted by supermarkus
What about bore wash in rich conditions? These cars already run a bit rich in stock form. Just what RPM range and engine load would this approach be appropriate?
I was just going to mention that. Bore wash seems to be something VERY few people know about.

~v6
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Old 01-24-2005, 04:40 PM   #10
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Default

Quote:
Originally Posted by SloRice
Due to my job, I talk with quite a few different customers about cars and tuning. Well Iíve been speaking with one of my customers about tuning turbocharged vehicles. He mainly works on turbocharged Mustangs.

The normal school of thought for increasing spool up is to lean out the A/F in the lower RPMís so that EGTís rise which creates a very high exhaust gas velocity. But after talking with this guy, he put a bug in my ear as far as this subject is concerned.

He says that instead of leaning it out, he richens it upÖ.a lot! While this does make your EGTís lower and exhaust gas velocity slower, it allows unburned fuel to go into the exhaust system which makes the exhaust gas much denser that if the fuel was completely burned off. He said heís seen spool up differences of 1000 RPM between the two styles of tuning. And itís not as hard on the motor because you arenít running dangerously lean in the lower RPMís. Is this the same school of thought as anti-lag?

The reason I put it in this forum is first off, I have one and I wanted to see if this style of tuning had any merit with the EJ257 motor. Also since lately companies are putting large turbos on the STI, it may open up doors to even larger turbos and more HP.

TIA,
Tim
Sales Engineer
Mustang Dynamometer
]

I have one piece of advice for you.

NEVER let this guy tune your car
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Old 01-24-2005, 04:46 PM   #11
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Default well..

in my understanding, bore wash occurs mainly in a low spark condition where u have useless dumped fuel into the motor...

we are speaking of a condition where we are on power with spark and combustion taking place??

info?

cb
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Old 01-24-2005, 04:48 PM   #12
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This subject has been discussed to death. I think if you search around you can find some good info and some graphs showing each way of tuning.

Tuning like this is not antilag. Its simply running a rich mixture during spool up with retarded timing. You typicaly run no more rich then the stock car does and its not damaging. If you tune like this you will bring map on faster. But the drawback is less power during spool up.

I tune for power and trq output at all RPM ranges. This makes for a more drivable and more powerfull engine with good response. I let the motor make its power until the turbo desides to come and make its power. I feel this is the best strategy. Some drag race cars use the rich fuel technique to get MAP on faster on the line. ONce going they never drop into the rich zone again. If you tune this way you can end up with maybe 500-1000 rpm of more power in the area just after or late in the spool up but before that you will make much less power.

Cya

Clark
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Old 01-24-2005, 04:52 PM   #13
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Default ...

each and every "package" has variables that affect the extent to which any of these tuning techniques comes into play....

obviously, if u have a low intertia quick spooling turbo? whats the point......

otherwise....if u have a big displacement motor than can make a good bit of normally aspirated power with some nice timing before u lean onto the turbo...whats the point...etc etc...

each set of variables requires its own solution (but there is always more than one)....

point was...the original comment was correct...some people do use that techinique...and in the way he mentioned, yes, it can increase spool up...

cb
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Old 01-24-2005, 05:45 PM   #14
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Well lets take my car for example. Basic engine mods are turboback, Blitz SUS Intake, UTEC.

What would be the best style of tuning for me? I don't have the UTEC in b/c it's been way to cold, but once I do, I'm planning on tuning it on our dyno. I don't care to make the most power, I just want to make the best power for autocross.
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Old 01-24-2005, 07:26 PM   #15
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There's a forum for this and the 2.5L one ain't it. Moving....
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Old 01-24-2005, 10:29 PM   #16
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Default

Quote:
Originally Posted by SloRice
Well lets take my car for example. Basic engine mods are turboback, Blitz SUS Intake, UTEC.

What would be the best style of tuning for me? I don't have the UTEC in b/c it's been way to cold, but once I do, I'm planning on tuning it on our dyno. I don't care to make the most power, I just want to make the best power for autocross.

Dude, you've got the best forum to test this theory than any of us and it's called your own! Seeing how you work for Mustang dyno you've got a better test bed than any of us. Test it and let us know.
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Old 01-25-2005, 09:35 AM   #17
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best power for autocross means best power across the board. aka, responsiveness.

as clark pointed out, the "motor power" is ALWAYS there--the "turbo power" is not.

i would tune for best torque at low rpm/map stages. that means in most cases afrs in the 13s or 14s, and timing somewhere in the high 20s. to hell with "spooling the turbo"--just let that happen in its own good time.

jm2c
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Old 01-25-2005, 09:53 AM   #18
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^^^^^
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Old 01-25-2005, 10:35 AM   #19
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Nothing new at all. Some tuners use this method to increase spool time but there is an extent to it.
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