Engine Surge

kwf1 · 08-27-2007, 02:37 PM

Re my C6, '06: when I downshift in any gear, but most noticeable when going from 4th to third or third to second, the lower gear does not immediately "catch" and start to de-celerate the car. Rather, feels like the engine just continues to surge forward at the same speed for about 2 seconds- then the lower gear "takes" and helps to de-celerate the car. Chevy dealer said this is normal on the Vette. Anyone else have this issue?

Thx/KWF1

Anti Venom · 08-27-2007, 04:13 PM

That is fairly common. On a modified car this is something that tuners have to work out. In the case of your car, has it been modified? Even if not, it can happen on a totally stock car as the programming is done in batches. Meaning that all cars with same options get the same program. Every car is different though due to production variances. GM just does not have time to custom program each car, so this type of thing happens. Quite often, there are enough cars with customer complaints that the engineers will write an updated program and this can be loaded by the dealership. The dealership will not notify you of any updated program, but if one is available for your concern, they will upload it for you. Otherwise, there is custom programming always available to you in the aftermarket.

**Rich Z** · 08-27-2007, 04:24 PM

Yeah, one thing you need to keep in mind is that when you manually shift gears in an automatic, you are simply REQUESTING the car to shift, not actually forcing it to do so. So the electronic brain is just slow to grant your request, apparently.

kwf1 · 08-31-2007, 08:55 AM

Thx to Anti Venom and Rich for their opinions on the trans/eng being in synch. My trans is a manual six-speed, so the lag time assoicated with an auto probably doesn't apply. The car has just two minor mods- Magnaflow Catback Exhaust w/x-pipe and SLP Blackwing air induction. However, the delay in the trans "gearing down the speed" has been evident since I purchased the car, so the mods had no affect on this particular issue. Would a re-tune help and if so, is there anyone in the Ft Myers/Naples area, or should I use Anti Venom? What would the cost be? Thanks! /KWF1