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Discussion Starter · #1 ·
Working on a GN motor swap. I originally had a SBC with a th400. My question is, how important is the VSS? I purchased a new harness from Caspers and they told me I didn't need the VSS function. Lately I've been reading that most chips a programmed to decrease boost and timing based on gear selection. Is there a way to have a chip programmed to ignore the VSS input? I've also read that a Max Effort 16 pos would probably be best for my application. Any feedback or suggestive input would be greatly appreciated - scott

southlandperformance.tripod.com

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The VSS also decides when to lock and unlock the torque converter in 3rd and 4th gear, turns the rad fan off at a certain speed, tells the ECM it is ok to purge the charcoal cannister, and activate deceleration fuel cutoff. Yes you can get the boost and timing tables altered in a chip, or just get the Boost Commander to control your boost, but why not pick one up from Caspers (I think he sells a Hall effect converter module that is used with a VDO 16 PPM sender) Dakota Digital sells a buffer and sender as well. I ended up making my own. Maybe some of the other guys will chime in with what the ended up using.

The Max Effort is a great setup and so is the Translator+ Extender chip combo. I guess it depends on what your plans are for the toy. The Max Effort leans more towards the larger injector race setups, but is reported by many to have excellent street manners. The Trans+ allows you to upgrade to a 3' or 3 1/2' Chevy MAF (LT1/LS1) and has many great features as well. (I went with the Trans+ and Extender chip and I am very happy with it. I know Scottie loves his Max E) Do a little search on the boards and you will get all the info you will need.

HTH

Paul
72 Toyota with a 87 TR drive train
 
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Discussion Starter · #3 ·
Thanx Paul- I appreciate the info. I forgot to mention that I am going to retain the th400 for cost reasons. It has a 8in 4000 stall convertor and just had a fresh rebuild before the chevy decided to check out. So you're saying that there is a way to get by and still be fast without the VSS? If so that's great news 'cause I've spent enough already and I'd like to get the thing running!! Thanx again! - Scott
 

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Scott.
You may have a problem with that converter. The stall is very high for the Buick motor, which builds all of it's torque and hp down low. (Most redline at around 5100 RPM) (Unless this is a built, race only motor?)
The stock D5 converter for the 200-4R stalls around 2200 (Depending on the Hp of the motor) and many guys are deep into the 11's with it. Others have gone up to a 3000 stall converter, but are running much bigger turbo's.

With the 400 you don't have any overdrive which will be a problem if you want this to be a street driven vehicle.
TH-400
lo 2.48 2.75
2 1.48 1.57
3 1.00 1.00

200-4R
Lo 2.78
2 1.57
3 1.00
4 0.67

It can be made to work, but this all depends on the rear end gear ratio and tire size you select, but most that have gone the 400 route are full time race setups.


You also mentioned that the 400 came from behind a Chev... You will need the BOP 400 tranny to bolt up to the Buick motor.
(You may be able to trade or sell the 400 and converter and get a 200-4R with a D5)

Sorry to put a damper on your project
but I hope I am saving you some grief later on down the road.
I don't know your skill level,(Obviously you have a bunch because of your precious swap) or how much you know about the Buick Turbo motor. So all I will say without insulting you, is that none of the Chey logic applies to this motor, and you have your work cut out for you with this swap. (It ain't just a bolt in )

Keep giving us details on what parts you have or want to get, and what you have done so far, and I'm sure the guys will lend their expertise in those problem areas you will come across.


Here are some misc. links to some info that you might find useful
http://www.jagsthatrun.com/ http://members.tripod.com/~grannys/index.html http://www.tciauto.com/tci.htm

HTH
Paul
 
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Discussion Starter · #5 ·
Paul- The motor has been in for about a month now. The chevy 400 is an easy bolt up to the GN motor. I just used an adapter plate that many companies sell. The convertor and VSS are my only concerns. The convertor stalls to 3000 on the foot brake and about 5000 on the T-brake with the SBC. The chevy put out about 500hp and 600lbs of torque. The GN motor I have will not be making anything close to that amount of torque or HP anytime soon. My understanding is that the the lower amount of torque = less stall. Is that correct?? The project will be complete when I get the electric water pump next week. I guess I'll know for sure then. BTW - I have 3.50 rearend gears so with the 28in tall tires I'm sure I'll be in the ballpark- Scott
 

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Hey Scott, thanks for the update on where you sit with the swap. I didn't realize that you were that far along.

When I first ran a stick with my setup, I didn't have a VSS. I hooked up a switch to the ECM P/N input (B10) so it would say I was in park and not throw a code 24 (VSS)while I was driving. I'm assuming the converter isn't a lock up anyway so you don't need to worry about ECM control. (Even if it is, you can wire up a manual switch). You can get past the 3rd and 4th gear boost scaling in the chip, by going tuner style with the wastegate or putting in a bleeder valve. Or just let your favorite chip burner know your setup and he will make the necessary adjustments.

Less HP = Less stall to a point. I'll leave this area to the experts. (Ask Bruce T. he will give you a definite answer)

Just curious... What made you go with the electric water pump?

Paul
 
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Discussion Starter · #8 ·
I went with an electric water pump for the simplicity and also for the ability to cool the car without the engine running in between rounds at the drags. I had one on the chevy motor and it worked great!! It's a little pricey but well worth it. Well hopefully this beast will be up and running in the next week or so. Thanx for all the info - Scott
 

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Does the max E use mph for any chip functions?
I can not provide any proof, but my Mazda started turning some impressive times at the track once I hooked the VSS up.

BTW - Getting the VSS signal to the Buick ECM is cake. Just buy one of the units from http://www.jagsthatrun.com and wire it up. One wire is ground, and the other goes to the ECM 'VSS'. I did just that on the RX-7 conversion. Go to http://www.MisRed.com and click 'Build Up'. Then click 'Guages', then click on the picture of the speedo. There is a picture of what the VSS looks like and how it's hooked up.

Hope that helps.

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'87 GN - Stock Block, Stock Cam, Stock Turbo, Stock Heads, V4, MSD50's, TH DP, JayJackson 62mm TB, 16position MaxEffort Chip. 3680# with Driver
11.92 @ 111.77mph

'87 Mazda RX-7 w/GN Powerplant
12.37 @ 122.26 MPH
Visit : http://www.MisRed.com

mailto:[email protected][email protected]</A>

[This message has been edited by Orlando_87GN (edited October 21, 2002).]
 
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Discussion Starter · #10 ·
So - you're saying that it should easy to hook the vss up to the th400?? My only concern is that when I bought the ecm harness from Caspers they said I didn't need the vss fuction so I don't think they built the harness with provisions for the VSS. Is there a way around this? If the vss only controls tcc lockup and cruise I'm not to worried since i have a N/L convertor and I won't hardely ever drive the vehicle on the freeway. I don't even think I can hook up the stock toyota speedo cable to the th400.
I'll take a peek and see. Thanx -scott
 

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You really don't need any VSS function since your converter is non-lockup. The VSS codes can be easily written out of the EPROM chip, and unless you're into highway cruise economy, there is no other function you should even need to worry about. P/N switch will disable the VSS code, but that can be easily written out as well. There are two idle tables in the chip, one for Park/Neutral and one for in gear, again, simple chip mod's will correct that. Also, your speedometer cable; you can take it to a speedometer shop and have them add the GM end to it for hookup to your trans.
-John Spina http://www.casperselectronics.com
 

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The VSS doesn't need to be part of the harness. It's a no brainer hook up. One wire off the sensor goes to ground, one goes to the ECM pin for VSS. Do yourself a favor and hook it up. It's easy. If you plan on racing the car and using a scan tool, the MPH reading will show up on your laptop or scan master ect...........

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'87 GN - Stock Block, Stock Cam, Stock Turbo, Stock Heads, V4, MSD50's, TH DP, JayJackson 62mm TB, 16position MaxEffort Chip. 3680# with Driver
11.92 @ 111.77mph

'87 Mazda RX-7 w/GN Powerplant
12.37 @ 122.26 MPH
Visit : http://www.MisRed.com

mailto:[email protected][email protected]</A>
 
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Discussion Starter · #13 ·
Yhanx for the help guys. It is much appreciated. I'm finally getting to the point I've got the SBCway of thinking out of my head and am starting to understand the GN v6 basics!! -scott
 
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