View Full Version : FYI: I'm running worser 1/8 mile times with forge
With stock DV i ran: 10.6+ secs
With forge DV i ran: 10.9 & 11 yesterday
As previously wrote: the forge DV holds boost firmer (so it works like it should), but the bosch DV (when not split) works BETTER with stock boost in my opinion.
The weaker bosch one seems to close later (maybe slower even?), giving a flatter torque curve with peak around 2.7k-3k RPM (dynoed) with less wheelspin and with a more progressive power delivery.
The stonger forge DV closes quickly (lets boost out of turbo a lot faster) giving a kick just above 2k-2.2k RPM (the charasteristic boos spike), BUT after this impressive kick, you can't feel anything just the decreasing torque and worser acceleration than with the stock one. Around 5k when BHP peaks you can feel something again, but i'm not impressed with the forge DV at all.
Probably it will work better than the stock on higher boost, but isn't really essential for standard cars at all. That's my opinion.
Anyone esle who got similar experiences?
ibizacupra
22-05-2002, 12:48
Originally posted by Sim
With stock DV i ran: 10.6+ secs
With forge DV i ran: 10.9 & 11 yesterday
As previously wrote: the forge DV holds boost firmer (so it works like it should), but the bosch DV (when not split) works BETTER with stock boost in my opinion.
The weaker bosch one seems to close later (maybe slower even?), giving a flatter torque curve with peak around 2.7k-3k RPM (dynoed) with less wheelspin and with a more progressive power delivery.
The stonger forge DV closes quickly (lets boost out of turbo a lot faster) giving a kick just above 2k-2.2k RPM (the charasteristic boos spike), BUT after this impressive kick, you can't feel anything just the decreasing torque and worser acceleration than with the stock one. Around 5k when BHP peaks you can feel something again, but i'm not impressed with the forge DV at all.
Probably it will work better than the stock on higher boost, but isn't really essential for standard cars at all. That's my opinion.
Anyone else who got similar experiences?
I don't see how a DV can effect the 2K rpm points you mention. On a 1/4 mile run you are'nt anywhere in that rpm range, when changing gears, as its the gear changes (lift off throttle) that the DV actually does anything. OR The DV just plain leaks? Have you checked for leaks past the piston seat?
Bill
Bill,
As i had the Forge DV on for some time how, i've decided to change back to the Bosch one to see (feel) the differences.
The car is actually a LOT (!) more impressive with the Forge DV as it gives better low down torque (that is 100% sure), so you don't have to trash the car to have huge amount of power (in normal everyday driving).
But as you state "On a 1/4 mile run you are'nt anywhere in that rpm range" -- as we're usually trashing the car, the stock one works better (for me), as it gives a flatter torque curve (torque coming in slowly) which you can benefit from (similar to the differences between Oettinger and APR chips).
I am sure however, that when a car is chipped, the forge DV would be quite advantageous (to keep the higher boost), also it recovers faster for true, but the stock setup doesn't really require one. My car got slower above ~3500 rpm!!! That exactly the same i felt for the very first time, it has got proven for me now.
PS.: My forge is in top condition, brand new (covered 200 miles), no leaks, etc...
I've just found my dyno plots from march (when car was totally standard with 1300 miles). Sadly i can't post a picture because i have no access to a scanner, but here it goes (sorry for newtonmeters, no clue about lb/fts):
at 2450 204 Nm (spike)
2450-2900 dropping to 196 Nm
2900-5100 nearly flat, ends on 192 Nm
5100-6800 smoothly drops to 147 Nm
This was with the bosch DV. I haven't dyoned the car since then, but i've replaced the exhaust and got a Forge DV006. As previously wrote, the Forge DV gives a lot more powerful kick (more torque) even from lower down AND on the other hand, i can definitely feel that the torque falls with an increased rate, resulting in worser 1/8 (1/4) mile runs. Will get both DVs dynoed in the near future to prove this.
I suspect it has something to do with the turbo (or ECU) attributes (no DV related problem at all). Like with the oettinger chip, you got a big spike in the beginning and then a constantly falling torque. Even if torque is more than the standard specs (with the chip) it is not as constant and massive as (it technically could be) lets say with the APR chip, which has no spikes or any kind of momentary overboosting at all. Maybe the turbo or ECU software reduces boost automatically after a bigger spike.
thats a peak torque of around 148lb ft
Having the stock DV back on again for some days now i can confirm that the torque peak (engine pull) is located at higher RPM. Actually i did like the more impressive low end torque with forge, so i'm putting it back soon. I'm not attending to do any 1/4, 1/8 mile runs till getting chipped.