how STUPID is it to run ONE aftermarket chip, instead of BOTH?
09-01-2002, 07:07 PM
#1
Drifting
Thread Starter
how STUPID is it to run ONE aftermarket chip, instead of BOTH?
Ok, so I posted about the set of Huntley chips I put in my Dad's '86 951. Turns out the KLR
chip is defective. Swapped the stock KLR chip back in, and the car seems to run well.
What possible issues am I facing (imminent disasters pending?) by running the Huntley DME chip and the stock KLR chip together?
I'm asking because the DME chip replacement seems to have had a positive effect on the mid RPM stumbling that I've been chasing on this car.
(of course, more testing is necessary
)
chip is defective. Swapped the stock KLR chip back in, and the car seems to run well.
What possible issues am I facing (imminent disasters pending?) by running the Huntley DME chip and the stock KLR chip together?
I'm asking because the DME chip replacement seems to have had a positive effect on the mid RPM stumbling that I've been chasing on this car.
(of course, more testing is necessary
)
09-01-2002, 07:21 PM
#2
Race Director
No harm, the only functional difference between the stock KLR and aftermarket ones is that the overboost-protection has been removed. As such, all aftermarket KLR chips should be the same.
09-01-2002, 07:28 PM
#3
Drifting
Thread Starter
well Danno, then the DME chip does what? Change the fuel curve? Rev limit?
on a side note, how is turbo performance improved via Huntley chips, which have no mechanical means of increasing boost (no banjo bolt, no shims)?
....I've got shims for the ol' wastegate, perhaps I should throw them in???
on a side note, how is turbo performance improved via Huntley chips, which have no mechanical means of increasing boost (no banjo bolt, no shims)?
....I've got shims for the ol' wastegate, perhaps I should throw them in???
09-01-2002, 08:31 PM
#4
Race Director
"well Danno, then the DME chip does what? Change the fuel curve? Rev limit?
on a side note, how is turbo performance improved via Huntley chips, which have no mechanical means of increasing boost (no banjo bolt, no shims)?
....I've got shims for the ol' wastegate, perhaps I should throw them in???"
Yes, you've got to increase the boost to get more power. The increase in power comes from getting more air into the engine. The chips just meter fuel to match that increased air-flow. And not many aftermarket chips do a good job of that, causing a super-rich mid-range and a lean high-end that causes your car to feel sluggish at partial-throttle/mid-RPM ranges. Here's a comparison of our full-throttle fuel-map compared to some others:
Notice that we dialed out the mid-range richness and added fuel up top where others take it away. This fuel-curve programmed into our chips came from dyno-testing we did to remove the mid-range richness from the Europroducts chips (<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=18&t=001921&p=1" target="_blank">Topic: Air Fuel Ratio under boost Question : </a>). However, <a href="http://boards.rennlist.com/upload/DanWorleyK27Stg2Chips.jpg" target="_blank">AutoThority</a>, Dinan, Porsche TurboCup and just about every other chip we tested had the same mid-range richness problem. Removing the mid-range richness gave us a 25% boost in mid-range torque and a lot less turbo-lag. This may be related to a bug in the air-flow conversion algorithm programmed into DME which doesn't quite calculate an injector pulse-width correctly even when given accurate air-flow data. Wanna get me a dyno-run with your Huntley chips? I'll even loan you our <a href="http://file:///ActualReality/WEBSITES/GURU%20Racing/website/ChipUpgrade.html" target="_blank">Chip Upgrade Kit</a> for a comparison...
Go ahead and throw those wastegate-shims in. They will increase the spring pre-load help keep your boost from dropping in the higher-RPMs when exhaust-pressure forces the wastegate valve open. This should raise your stock 11.5psi boost up to around 13.0psi. This will push you right up to the overboost-protection limit of the stock KLR chip. Although you might have one of those top-secret super-agent cars like Luke that doesn't activate overboost-protection no matter what you do. You'll know for sure when that kicks in though! It'll feel like you've hit a brick-wall, so make sure you're wearing your seatbelts before laying into the gas.
However, since you're only running 13psi instead of 15psi, you'll have too rich of a mixture and the car will be sluggish. I recommend getting a replacement KLR chip so you can remove the overboost-protection. Then get a <a href="http://www.controlair.com/regulators/850_860reg.html" target="_blank">low-pressure air-regulator valve</a> and dial up the boost the rest of the way to 15psi.
As far as the rev-limiter goes, we kept the stock 6480rpm limit. With most people running into 100% injector duty-cycle at around 6000rpm with our MAP-sensor upgrade kit (+free-flow exhaust), we don't want to be pushing any further.
on a side note, how is turbo performance improved via Huntley chips, which have no mechanical means of increasing boost (no banjo bolt, no shims)?
....I've got shims for the ol' wastegate, perhaps I should throw them in???"
Yes, you've got to increase the boost to get more power. The increase in power comes from getting more air into the engine. The chips just meter fuel to match that increased air-flow. And not many aftermarket chips do a good job of that, causing a super-rich mid-range and a lean high-end that causes your car to feel sluggish at partial-throttle/mid-RPM ranges. Here's a comparison of our full-throttle fuel-map compared to some others:
Notice that we dialed out the mid-range richness and added fuel up top where others take it away. This fuel-curve programmed into our chips came from dyno-testing we did to remove the mid-range richness from the Europroducts chips (<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=18&t=001921&p=1" target="_blank">Topic: Air Fuel Ratio under boost Question : </a>). However, <a href="http://boards.rennlist.com/upload/DanWorleyK27Stg2Chips.jpg" target="_blank">AutoThority</a>, Dinan, Porsche TurboCup and just about every other chip we tested had the same mid-range richness problem. Removing the mid-range richness gave us a 25% boost in mid-range torque and a lot less turbo-lag. This may be related to a bug in the air-flow conversion algorithm programmed into DME which doesn't quite calculate an injector pulse-width correctly even when given accurate air-flow data. Wanna get me a dyno-run with your Huntley chips? I'll even loan you our <a href="http://file:///ActualReality/WEBSITES/GURU%20Racing/website/ChipUpgrade.html" target="_blank">Chip Upgrade Kit</a> for a comparison...
Go ahead and throw those wastegate-shims in. They will increase the spring pre-load help keep your boost from dropping in the higher-RPMs when exhaust-pressure forces the wastegate valve open. This should raise your stock 11.5psi boost up to around 13.0psi. This will push you right up to the overboost-protection limit of the stock KLR chip. Although you might have one of those top-secret super-agent cars like Luke that doesn't activate overboost-protection no matter what you do. You'll know for sure when that kicks in though! It'll feel like you've hit a brick-wall, so make sure you're wearing your seatbelts before laying into the gas.
However, since you're only running 13psi instead of 15psi, you'll have too rich of a mixture and the car will be sluggish. I recommend getting a replacement KLR chip so you can remove the overboost-protection. Then get a <a href="http://www.controlair.com/regulators/850_860reg.html" target="_blank">low-pressure air-regulator valve</a> and dial up the boost the rest of the way to 15psi.
As far as the rev-limiter goes, we kept the stock 6480rpm limit. With most people running into 100% injector duty-cycle at around 6000rpm with our MAP-sensor upgrade kit (+free-flow exhaust), we don't want to be pushing any further.
09-02-2002, 12:13 AM
#5
Addict
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Danno, I will be doing a dyno run pretty soon (if I can hold that pile of junk together!) and I'll take the pepsi challange with your chips if you're OK with that. My car now has europroducts chips. If you're up for it send me an e-mail we'll talk details.
Ahmet
Ahmet
09-02-2002, 02:41 AM
#6
[quote]not many aftermarket chips do a good job of that, causing a super-rich mid-range and a lean high-end that causes your car to feel sluggish at partial-throttle/mid-RPM ranges <hr></blockquote>
How about the original chips? Are they also rich on mid-range and lean hih-end ? Any charts available ?
Olli
'88 951
How about the original chips? Are they also rich on mid-range and lean hih-end ? Any charts available ?
Olli
'88 951
09-02-2002, 08:47 AM
#7
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the stoch chips are perfect for economy and emission.
The APE are ad some extar fuel in the middle and very little more at the top. The timimins is much more agressive
The HR chipa re add a LOT of fuel overall but the timming is not that agressive(but much more agressive than the stock chips)
You cxan run much more boost and more safer with the HR chips but I expect the APE to make some extar HP on a stock car with only chip upgrade.
I doubt you will notice teh difference since it will be ~5-8 hp
The idle and the part throttle til 20% is the same for all the chips
Konstantin
The APE are ad some extar fuel in the middle and very little more at the top. The timimins is much more agressive
The HR chipa re add a LOT of fuel overall but the timming is not that agressive(but much more agressive than the stock chips)
You cxan run much more boost and more safer with the HR chips but I expect the APE to make some extar HP on a stock car with only chip upgrade.
I doubt you will notice teh difference since it will be ~5-8 hp
The idle and the part throttle til 20% is the same for all the chips
Konstantin
