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Na-t set up / need help with speed cut

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Old 02-04-16, 01:24 PM
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Aswilley
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Default Na-t set up / need help with speed cut

So as many of you know I have finished my NA-T set up on 15psi stock SC300 Trans using a factory Aristo ECU. However I am running into an issue with speed limit cut at around 119 MPH -125 MPH or approximately 180 KM/H. This makes sense cause of Japanese Speed Laws, however here in Colorado we have an annual track event called Pikes Peak Air Strip Attack.

People from all over come to set top trap speeds in anything from a Honda Civic to a Lamborghini Hurrican.. last year the record went to my friend George in his Volvo, who trapped a speed of 182.33 MPH.. I would love to compete except my Aristo ECU will only allow me 120 MPH.. which means I qualify in the same class as an 90's Ford SHO

currently the car is on 15psi and doesn't his boost cut somehow, but caps out pretty quick on speed. My question is :

Does anyone here know what type of speed cut controller works with an Aristo ECU?

Will an HKS Speed Limit Defencer will work? and dose anyone know how to wire it in? all of the instructions are in Japanese

I am not spending the money to go stand-alone ecu until I swap to 5 or 6 speed.. and at that point the car will be set up for a rounded array of events including light drifting, speed trap contest, and drag ..

thanks for any help with this in advance
Old 02-04-16, 02:23 PM
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Ali SC3
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The ecu needs the speed signal to shift on auto trans cars.

HKS speed defencer comes in 2 types.
type 1 is for a manual (you can also just disconnect the speed wire going into the ecu)

type 2 is for automatic and actually is more complicated cause it lets ecu see speed up until the point where it gets bypassed, think of this like a boost cut controller except the speed signal is not a voltage, its a puled signal.

you need the correct type for your auto car if you want it to shift properly and give speed cut, or you can go to a manual transmission. I may have read a while back where someone put a switch on the speed signal and would just cut it off in 4th gear manually but I have no idea how well that would work on an auto car but it would work fine on a manual car.

I have encountered it a few times, its not very pleasant its basically like a boost cut except always around 110mph give or take a little.

the one for auto is type 2 like 8 wires, then there is another one for aristo called "hks sld t6" which is 16 wires maybe. I think you just need the type 2 not sure about the t6 maybe thats for a newer model aristo.
http://www.supraforums.com/forum/sho...limit-defencer
http://www.lexusownersclub.co.uk/for...6-wiring-info/

Last edited by Ali SC3; 02-04-16 at 02:29 PM.
Old 02-04-16, 02:53 PM
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Kris9884
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Does this limiter issue happen in generally all JDM ECU's?
Old 02-04-16, 03:47 PM
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Aswilley
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Originally Posted by Kris9884
Does this limiter issue happen in generally all JDM ECU's?
from my understandings, yes. Due to Japanese speed limit laws, manufactures automatically limit all production cars to 180 KM/H. I have heard but cannot confirm that Standard transmission cars over there are capable of 156 MPH ish.
Old 02-04-16, 03:57 PM
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Aswilley
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Originally Posted by Ali SC3
The ecu needs the speed signal to shift on auto trans cars.

HKS speed defencer comes in 2 types.
type 1 is for a manual (you can also just disconnect the speed wire going into the ecu)

type 2 is for automatic and actually is more complicated cause it lets ecu see speed up until the point where it gets bypassed, think of this like a boost cut controller except the speed signal is not a voltage, its a puled signal.

you need the correct type for your auto car if you want it to shift properly and give speed cut, or you can go to a manual transmission. I may have read a while back where someone put a switch on the speed signal and would just cut it off in 4th gear manually but I have no idea how well that would work on an auto car but it would work fine on a manual car.

I have encountered it a few times, its not very pleasant its basically like a boost cut except always around 110mph give or take a little.

the one for auto is type 2 like 8 wires, then there is another one for aristo called "hks sld t6" which is 16 wires maybe. I think you just need the type 2 not sure about the t6 maybe thats for a newer model aristo.
http://www.supraforums.com/forum/sho...limit-defencer
http://www.lexusownersclub.co.uk/for...6-wiring-info/
Thanks Ali SC3 ! I knew speed cut on an auto was gong to be a bit of a task to figure out without going stand-alone. Do you happen to know if I may need the SLD T6 as I am using the Aristo ECU/TCM but it is rewired for the SC fatory dizzy harness.. I also thought the type 2 would probably work just fine since I don't actually have the TT Trans

Last edited by Aswilley; 02-04-16 at 04:17 PM.
Old 02-04-16, 08:04 PM
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Ali SC3
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I think you just need the type 2.

yeah most jdm ecu's will cut at 110mph, aristo, supra both.
US ecu's are 155mph give or take a little bit.
Old 02-05-16, 08:39 AM
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While spendy (300-500), rare and a bit hard to find at times, you could also look for an original gforce moded factory ecu as they all have the speed cut removed, larger injector map, rpm limit raised or removed, fixes an upper end lean spot, and a few other options. They show up on sf from time to time. There was also a company called mines that made moded aristo ecu's but haven't seen one of those in some time now. Solves the problem without needing a separate unit.
Old 02-05-16, 12:41 PM
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Originally Posted by scblackout
While spendy (300-500), rare and a bit hard to find at times, you could also look for an original gforce moded factory ecu as they all have the speed cut removed, larger injector map, rpm limit raised or removed, fixes an upper end lean spot, and a few other options. They show up on sf from time to time. There was also a company called mines that made moded aristo ecu's but haven't seen one of those in some time now. Solves the problem without needing a separate unit.
I almost bit the bullet on a Mines Soarer ECU for $450 on eBay a while back but I am glad I didn't cause I realized it was legit and that means it was for a 1JZ not a 2JZ.. SCBlackout of I can get my hands on an Aristo Mines ECU I would spend a left nut for it lmao.. that means no rewiring .. PNP .. I'm so in .. but until I see one for the next 5 years I guess I'm stuck with the HKS SLD Type 2 lmao.
Old 02-05-16, 02:34 PM
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well guys I hope something pops up.. I posted in the GS and SC Classifieds to see if a JZS147 Mines Tuned Aristo ECU is floating around the forums somewhere. maybe I will get lucky and someone will be willing to part with one, or know s someone with one.

P.S. Thanks admin for moving to the correct section
Old 02-05-16, 02:54 PM
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I have no idea what the difference between mines and gforce is, but there are a couple available on sf.
http://www.supraforums.com/forum/sho...ghlight=gforce
http://www.supraforums.com/forum/sho...ghlight=gforce

It seems that there is 1-2 mines and gforce ecu's that show up each year on sf. The biggest problem I have seen is finding out exactly what was done to each ecu as they all appear to have different settings. I personally got lucky and was able to track down the original owner of the gforce I purchased so was able to find out the exact changes made. --- 9500 rpm, speed limit removed, fuel and timing for 1000cc, lean spot removed. I'm still in the process of gathering all the parts needed for the project so can't personally vouch for how they work, but I assume they are good as the build threads using them all are very positive.

Best of luck with your search.
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