Bill Hahn Jr. wrote:I'd like to interject something here...fuel cut rev limiters are actually the best method. They do not cause an engine to run 'lean', for the very definition of 'lean' is insufficient fuel, not non-existent fuel.
Bear in mind: what do we typically fear from a lean condition? Detonation! But detonation still requires fuel...take away the fuel altogether, and you also take away any possibility of detonation. Air alone will not detonate!
Why is the fuel cut rev limit preferred? Well, once we understand the above, we can consider what 'interrupting' the spark (the other method of rev control) does to the engine. As we take away interspersed ignition pulses, we cause a very unstable condition to a very smooth-revving engine. The cylinder fires, then it doesn't, then it does, then it doesn't...mechanical parts are being jacked around, unevenly unloaded, then instantly reloaded...unburned/partially burned fuel causes all kinds of instabilities in the cylinder, as well as intake and exhaust systems...oddball pressure waves are caused in the manifolding...backfires often occur. Use your imagination and think about what's going on in there as the spark turns on/off repeatedly. It's just wrong on so many levels, and your engine HATES it, especilly when it's at its most tender condition...maximum RPM!
I stand corrected, and that is exactly the type of response I was looking for! Thank you for the info.
15.3 @ 89.97mph, 14's on the way?
Bill Hahn Jr. wrote:I'd like to interject something here...fuel cut rev limiters are actually the best method. They do not cause an engine to run 'lean', for the very definition of 'lean' is insufficient fuel, not non-existent fuel.
Bear in mind: what do we typically fear from a lean condition? Detonation! But detonation still requires fuel...take away the fuel altogether, and you also take away any possibility of detonation. Air alone will not detonate!
Why is the fuel cut rev limit preferred? Well, once we understand the above, we can consider what 'interrupting' the spark (the other method of rev control) does to the engine. As we take away interspersed ignition pulses, we cause a very unstable condition to a very smooth-revving engine. The cylinder fires, then it doesn't, then it does, then it doesn't...mechanical parts are being jacked around, unevenly unloaded, then instantly reloaded...unburned/partially burned fuel causes all kinds of instabilities in the cylinder, as well as intake and exhaust systems...oddball pressure waves are caused in the manifolding...backfires often occur. Use your imagination and think about what's going on in there as the spark turns on/off repeatedly. It's just wrong on so many levels, and your engine HATES it, especilly when it's at its most tender condition...maximum RPM!
The inertial load (the force on the rods and bearings when the piston accelerates/decelerates from a complete stop to maximum velocity) is the real issue here as the engine goes from full power to nothing at the rev limit. This happens regardless of fuel cut or spark cut. It's a huge shock load to the bearings and i bet the crank doesn't like it too much either
This is why manufacturers have moved to the fast acting and highly accurate electronic throttle as the primary method to control engine torque (and hence RPM). If you ever see an LS2 V8 hit the RPM limit you'll be quite surprised how civilized it all is, compared to the bucking fuel cut.
I used to have an old 383 SBC that could throw a 3ft flame from dual exhausts by cutting ignition at 7000rpm and holding your your foot to the floor, then keying on just before it stalled
OMG what a noise!! A neat party trick
Ahhhhh the memories....
I wonder when someone will actually start another thread
This one seems to cover an awful lot....
yes it covers alot BUT is very interesting and VERY informative
The one, the only, ME.
,
F$%K ILLSTREET.COM
what kind of gains can be had by changing the torque management options?
14.728 @ 92.14 (65 shot)
what kind of things can be done to the 4spd auto? any ways to get one into the 14's n/a
14.728 @ 92.14 (65 shot)
^^^^^^^^^ listening on your first question
itll take more then just tuning to get an auto into the 14's BUT it should be a big help
The one, the only, ME.
,
F$%K ILLSTREET.COM
Damn for 499.00 I would think you should be allowed to do unlimited tuning without having to buy credits and such... NOT complaining though
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD
AUTOMATIC!!
328 HP
306 TQ
WHITECAVY wrote:Damn for 499.00 I would think you should be allowed to do unlimited tuning without having to buy credits and such... NOT complaining though
You get 8 credits, costs 2 to do unlimited tuning to one car, so for $500 you can tune 4 vehicles.... I think thats a damn good deal.
4cyltuner.com - Information Source For 4 Cylinder Tuners
Buy stuff from CarCustoms Ebay! Won't be disappointed!
nathan121 wrote:what kind of things can be done to the 4spd auto? any ways to get one into the 14's n/a
Probably with some bolt ons (I/H/E) on a 2.4 or eco. You can adjust all the shift tables you want, fueling, spark, etc. There is a list on the first post with the editable parameters for my 4 speed.
4cyltuner.com - Information Source For 4 Cylinder Tuners
Buy stuff from CarCustoms Ebay! Won't be disappointed!
Its still a drag though, id love to hook up all my friends Js only 2 ppl I know even have an 02
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
I emailed Chris a couple days ago asking if there were any new developments on the issue of getting hp tuners to work with the ecotec gm s/c reflash or if there had been any progress, his reply was...
There's nothing much i can do about it unfortunately.
Chris...
So I guess the eco reflash guys are kind of out of luck. So I was wondering what everyone else in this situation is doing? Any other ideas? Going back to stock pcm then trying to use hp tuners? Anyone?
Got a question on the credits. year/model. means you can do work on any vehicle of that year/and model for a year. Then you need 6 more credits once the year is up?
Alright. That is what I was sure of cause it almost look like it read per year you had to have 6 credits on the site. Thanks for clearing that up.
Well an update, Jimmy99Z at 607 tuning has been tuning my car with HP tuners in Corning NY. Two days ago the computer quit and nothing worked, so I got a new computer and now it is up and running again. The car will still be slower than shiot because of the damn lowered compression to 9.0.1, which was the supidest thing I ever did. So GM SC, 9.0.1 compression, 2.6 inch puley etc, and the car is struggling to get out of the 15s, I hate my car, lol.
I will get more updates shortly.
http://members.cardomain.com/vertz24 1998 Z24 Convertible
i hear ya except i called my machine shop and they told me my comp was 9.2 not 9.0 so it isn't gonna be that bad
besides i am starting an m62 project on the car
hehehehehe
20psi here i come
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Why would someone want to disable the vats with hptuners. A quick search of vats came back with vehicle anti thefts system. Why wouldn't you want this.
to install a command start :shrug
HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED
crabgrass wrote:Why would someone want to disable the vats with hptuners. A quick search of vats came back with vehicle anti thefts system. Why wouldn't you want this.
When you change the ECU programming to one that didn't come with the car, (IE the security code in the ECU doesn't match the code in the BCM), the car won't start. HPT doesn't give us the ability to relink the VATS (yet), so if you want your car to run with somebody elses tune, you will have to turn off VATS. VATS doesn't keep your car from getting stolen, its actually pretty ineffective, it just won't let the car run without a key in the ignition, or the correct PCM/BCM combo in the car.
4cyltuner.com - Information Source For 4 Cylinder Tuners
Buy stuff from CarCustoms Ebay! Won't be disappointed!
^^oh. So someone can e-mail me their flash they have customized, And i can put that into my ecu. But only after i have disabled the vats. If i read correctly thats way you would want to turn it off.
I just ordered the hptuners program. But i am going to be running the protfueler. So all i need if for is to change
my close loop/open settings anyway. Maybe change my timing.
i only ordered it on Thursday and i already got an e-mail with instructions on it. so it shouldn't be long.
