The way I have this thing hooked up is from the yellow wire off the trans, I have tried other ways but this is the only way I made it work. The problem I have is my speedo bounces below 60km/h(40mph). I all so used my friends GPS unit to set my speed and I found out that under 60km/h its 5km/h slow, between 80km/h and 130km/h its bang on, and at 140km/h and higher its 5km/h fast WTF?. So my question is, is this normal or what?


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89 GTA 350 5-speed
Jet hot coated SLP headers,flowmaster force 2,no cat's,SLP cold air,MSD 6al,jet chip stage 2,march pulleys,ported plenum,air foil,B&M ripper shifter,180 stat,alston SFC,spohn LCA relocation brackets,MAT relocation kit,free mods.

0-60 5.48s
E.T. 14.02@98.9MPH (corrected)

 

That doesn't sound unreasonable to me, analog speedometers aren't always 100% accurate.

 

Well, not a 100% but if everything's correct, they can be damn close.. There's only one way to do the math...

I'm focusing on your tire size maybe...