I was wondering if something with 4k springs could tell me how the truck drives with them. I ordered them for my truck and have yet to put them on. Right now my truck's only useful RPM range is idle-2000rpm. After 2 grand the truck pretty much stops moving and just turns the engine harder and is about useless. It will spin up to 27-2800rpm though. I was wondering at what RPM with the 4k's that the engine starts to lose it's get up and go and what the new usable RPM range will be?

 

I don't know about the 4000, but with the 3000 the power keeps coming on. I have read thet the 4K fuels even better through the 2000 range

 

the 4k springs make the truck a little jumppy and the throttle is really touchy. it does not take much pedel to get the truck up to speed just put it that way.
DM01

 

You will also need to change out your valve springs when installing and using the 4gsk kit if you do not already know this, I have the 3gsk's in mine which does not require the heavier valve springs and they are excellent and they help immensley when using the truck to pull in the hills as I can stretch the gear selection out. Pardon me I just noticed you had the heavier valve springs listed in your signature. You will enjoy the big difference you now will have in the range of rmps to use your truck. Goodluck,,, Rick

 

I had the 4k springs and could not get them exactly right. They are very touchy. I put the 3k's in and they seemed to be much more streetable. This may just be me. Good luck.
Justin

 

Is it possible that on trucks with lots of mileage the gov spring get tired and let you turn more RPM? My truck spent 354000km of it's life factory stock and now at 423000km it has the mods listed in my sig. It has always fueled to 2800rpm. Are my springs worn out or do I not get the idea of a GSK?
Second set of questions. What are the downsides to the 4K gsk? I would love to hear my truck @ 4000rpm. As always thanks for any responses

 

I totally agree. The 3K springs are the choice for the street. When I put my truck on the strip, I shifted at 3200 RPM. On the dyno David spun the truck to 3400. I told him not to get that much again. I really do not like to push my truck up there. That give's you an idea.

..Preston..

 

I don't get to use the full 4k because my lift pump is out and it will not fuell up past 2800rpm. but that will all change this weekend. they are tricky to drive but just a little fine tunning on the springs will make the truck run a lot better.
DM01

 

I have them in my truck lovem but they hard to get used to at first dont just let anybody drive your truck either cause it will buck more than a bucking bull, I have turned mine once or twice maybe three times 4000k and let me tell you it will run too pulss all the way through it...Good luck and hope you ordered Piers or TSTs they are the two best...

 

Had them installed by Piers when he was @ BD ... 4 or 5 yrs ago? Anyway, no complaints. Can't tell any driveability differences.

I haven't run mine all the way up yet. Just don't run it that hard. Once, I ran to 3300 to 3500, still had bandwidth left.

I like the extra RPM for those pesky WRX's. A smaller #'d plate & gov springs makes that long gap between a couple of the gears go away.