why should i use a spring on the wastegate?
 

i got my turbo civic running recently, and i did absolutely nothing to the wastegate actuator, other than to just run the line from the compressor housing to it. while the boost level was a very very dangerous 12psi coupled with some detonation, the spool-up was absolutely incredible. i was seeing about 6psi by 2500, and the 12psi by about 3500.

my question is, will the 'spring trick' get me my spool-up back? or is it going to be just like my now ghetto-rigged actuator where i dont see my full 7psi until just after vtec? i cannot make any boost at anything under 4k unless i go WOT.

details are d16z6, and a dsm t25 with the dsm smic.

Re:why should i use a spring on the wastegate?
 

i never have used the sring trick. but what i have read i guess it will get u by,but its not the greatest thing in the world. the spring will heat up after running the car and u will not get full boost. someone that has used this help him out. i know it has be discused here befor.

Re:why should i use a spring on the wastegate?
 

the reason i dont really like the spring trick is that its not referenced off of boost at all. it certainly gets the job done of applying a force to the wastegate, but i really dont like how its not working from a pressure reading.

one thought i had would be to use a pressure sensor and an analog voltage comparator. if the calibration of the pressure sensor is known , you could drive a servo to get the boost pressure to the desired amount. the analog part would provide some 'damping' so that its not just an open/close type deal.

another way would be to make my own wastegate actuator. basically taking the spring out of the stock dsm one, and making the wastegate diaphram have a larger area so that a lower boost pressure would give the same wastegate actuator movement. the problem with this as compared to the electronic actuator is that this will give a slower spool-up.

Re:why should i use a spring on the wastegate?
 

The spring trick sucks I am using a spring while I rig up a hanger for my wastegate actuator no matter how tight I pull the spring i only get 6 to 7 lbs of boost. Fix your wastegate it is hands down better

Re:why should i use a spring on the wastegate?
 

Ok, first you say you're boosting 12psi by 3800 rpm then you say you don't get full boost of 7psi at 7000 rpm. Ever thought of just buying another wastegate? they're on ebay now for $20! Buy a 6-8psi w/g and if you want to turn up the boost later you can buy a Boost controler or build one. You could always lengthen the actuator arm but they say that'll give you more boost lag.

Re:why should i use a spring on the wastegate?
 

i was using the spring trick method make sure you have the correct tension...its takes longer to hit full boost though

Re:why should i use a spring on the wastegate?
 

sorry if there was any confusion, but i said that with the wastegate actuator bolted onto the compressor housing just like it would be stock, i was getting 12 psi by about 3500rpm. trying to get the boost down, i shimmed the wastegate actuator over with washers, and was able to lower the boost to around 7psi, but with pretty bad lag due to the wastegate not sealing. so i was not seeing full boost until just after vtec. if you read my posts more carefully, you would have seen that :P

the dsm T25 has an internal wastegate, so i cant just buy a new wastegate off ebay. i could try a different actuator, but getting one that will fit looks to be pretty much a waste of time.

what i am asking here is whether or not doing the spring trick will get rid of my lag problems. thank you turbodxcoupe for letting me know that the spring trick does not reduce the lag.

Re:why should i use a spring on the wastegate?
 

here's a thought: use the actuator as it's designed (normally 12 psi or whatever), but rig an extra spring to pull the actuator arm toward it's open position. the idea being not to hold the waste gate open, but simply to weaken the pull of the spring in the actuator, allowing it to move at lower boost pressures.

Re:why should i use a spring on the wastegate?
 

i wouldn't go ------- with the actuator, boost surge can kill.


Dump the cat and get a decent exhaust.. then you'll be in the 3k spool club for sure.

Re:why should i use a spring on the wastegate?
 

already have... and im not :P


being the geek that i am, im currently thinking about making an electronic actuator. there are a couple ways to go, the simplest being a depth controller out of a radio control submarine hooked to a strong and fast servo... all this being remotely mounted and actuating through a cable

my roommate thinks i should use something called a PIC controller and use either a linear stepper motor, or the motor out of an electronic cruise control system (much like the one on a civic)

there are some very nice advantages to this idea, in that the wastegate (at least in theory) will absolutely not be leaking until my circuitry lets it. end result would be hella fast spool time ;D problems would be the life of the motor, as it would be seeing ALOT of use.