part throttle boost
 

just wondering if any of you with aftermarket turbo kits see part throttle boost and if so how do you control it....

Re: part throttle boost
 

they are going to flame you.

if you have boost in front of the throttle when you are at part throttle that is a good thing for drivability and throttle response.

the answer is however, with the throttle dumb arse! lol

the bov will release the excess if you lift too much, and the wastegate will keep it low enough on that side if you havent lifted enough to actuate the bov.

good luck with the abuse you are probably about to suffer.

Re: part throttle boost
 

u obviously don't understand the question...i am well aware of what a wastegate and a blow off valve do...i understand boost is a good thing but when im at about half throttle and it will keep creeping till it hits 15 psi i get concerned about the afr... just wondering if any of you use some kind of boost solenoid?

Re: part throttle boost
 

I would suggest a larger turbo first. Otherwise, you could use an EBC to keep your boost at a low setting then raise it when you need to. What kind of wastegate are you using? Just remember that you can't go lower than what the base boost setting of your wastegate is generally.

Re: part throttle boost
 

what is your setup...if its creeping above what it should be at wot then there is a problem

Re: part throttle boost
 

on my car i took the wastegate line off of the solenoid because it won't really let it boost over 15 psi. i replaced the wastegate with an adjustable high pressure wastegate so i could turn the boost up... now that it is off the solenoid, it is getting mad boost creep... i just want to know if there is some way to reduce part throttle boost creep because im putting a turbo on my bike and want to avoid this...

Re: part throttle boost
 

what car is this...give more details. What are you using as your wg boost source, what is your boost at full throttle

Re: part throttle boost
 

i drive an srt-4 and on the stock solenoid it will hit 18 psi and hold about 15 with an after market gate... if you take it off of the solenoid it will boost more but you get this nasty boost creep at half throttle... im turbocharging my motorcycle and since it is not factory turbo it will not have anything to control the part throttle boost just wondering what i could use...

Re: part throttle boost
 

so your wg has no signal line hooked up to it at all? thats not good.

Re: part throttle boost
 

no, it does i just removed the solenoid in the signal line so i could get more boost

Re: part throttle boost
 

15psi at 1/2 throttle? My 14b doesn't even creep past 3psi at part throttle. That's funky dude.

Re: part throttle boost
 

Your turbo shouldn't be building boost at part throttle cruising.

I can't even think what would cause that, there shouldn't be enough gas to move it faster than the flow of the exhaust gas. When cruising it's just like an N/A car.

Can you give a bit more detail as to how Dodge controls the boost? Seems to be electronically gated but even then you wouldn't see massive boost at cruise or part throttle.

Re: part throttle boost
 

I had a T3/T04E with a .48 exhaust housing on an LS and i would get 5 psi cruising at 1/2 throttle. I loved it. Driving up hills and passing on the highway was great.

Re: part throttle boost
 

My brother in law had a srt4 and when he put his forge wg on his srt4 it would give him mad part throttle boost. But your srt has a knock sensor so if you get any kind of det your ecu will pull timing. But since you arnt really putting a huge load on your car I dont think it would be a big deal. The way we fixed this is we put a bigger turbo on the car and went with a external wg. (have you seen how small the stock turbo is? the wg port is tiny on the thing)

Re: part throttle boost
 

is this cursing at a set speed or accelerating part throttle

Re: part throttle boost
 

stenseltizm definitely made several pounds of boost at less than half throttle, in a LS teg, with a hx35.

Re: part throttle boost
 

its really not a bad thing imho...boost=fun

Re: part throttle boost
 

haha , ya boost is fun i was just curious... im not so much worried about it on my car, im more worried that im gonna be on my bike at 6k rpms and boost will start creeping... but ya it is no cruising, its during acceleration... and no it is not an electric gate...

Re: part throttle boost
 

it sounds like your wastegate boost source is on the engine side of the throttle, if this is the case, when you lift, will go low and close the wastegate INCREASING the boost in front of the throttle and thereby forcing it to flow more air to the engine.

think of the throttle like a divider of pressure, these figures are random and way off, but it will illustrate the point :

15psi, you lift to half throttle, you end up with 5psi in the intake manifold and 15psi behind it, but plenty of exhaust gas exiting the engine.

because the wastegate now sees 5psi, it closes and increases turbine speed to try and obtain 15psi BEHIND the throttle thereby potentially increasing it way above 15psi between the compressor and throttle.

i cant see any other way that would happen either unless you have it plumbed wrongly. fiy, i also have mine plumbed wrongly, and experienced a similar thing. i'll fix it as soon as i get back to my project.

if you have it plumbed correctly ... if your speed and therefore engine speed is increasing, then you could be outflowing the wastegate and building more boost that way i guess. either way, if its 15psi on the engine side, its sure as hell higher on the other side!

fred.

Re: part throttle boost
 

plenty of people have their wg signal line coming from the intake manifold. Who cares what the boost is at before the IM anyway. When you lift, the wg is going to close to try to maintain the same pressure no matter where the wg source is coming from, thats how it works. It is always trying to maintain the same boost pressure (whatever psi it is set for).

Re: part throttle boost
 

For real, I only recently put my WG signal line on the charge piping, I had it coming off the IM for months and never had a problem.

Re: part throttle boost
 

personally, i dont give a ---- what everyone does.

http://www.tialmedia.com/documents/w..._wginstall.pdf

i give a ---- about what is correct.

you are increasing back pressure unnecessarily, increasing engine temperature, and putting undue stress on the diaphragm by having it hooked up like that, plus, you will experience part throttle increases like that which makes it VERY difficult to control torque to the wheels! (do any of you ever use part throttle?? :-p)

anyway, yes its wrong, and yes, i did it wrong too, and no its not good for a number of reasons.

as was recently said in another thread "hmt doesnt have to mean niggarigged, just made at home" so why not do it right, its only moving a hose 6" or so anyway.

fred.

Re: part throttle boost
 

YOUR BOOST IS TOO HIGH!

Turbo your boost down to 7psi then take it from there.

if you turning down the boost and it stays the same(does not go down)

then you got a problem. Start doing the check's! check that everything is in its correct place and secured. then check your vacuum lines for any leaks /cracks..

if i pull the Vaccum line off my Actuator i will have the same effect as your are discribing. the car will boost to infinity..

Re: part throttle boost
 

unless i missed something, his boost regulates correctly and nicely under WOT conditions.

also, he shouldnt expect good answers when he asks the question in a random way. dude, note how many of the responses are questions, and how many are suggestions, and how many of those suggestions are relevant...

Re: part throttle boost
 

Okie So under full Boost flat foot acceleration Wide Open Throttle everything is 100%

is he using internal or external wastre gate? cos there is a Cheap ANTILAG System (Vacuum Lines route) that will allow the car to OVERBOOST. and reduce waste gate creep so inconjuctions with this and a small turbo. i could see this happening...

Re: part throttle boost
 

Its perfectly normal, all srt4s have part throttle boost, especially when you add an aftermarket wastgate. You either drive like a grandma and not worry about it, or you drive wot everywhere. I could have the pedal half way down and it will creep up to 10lbs. It does cause a lean condition, but nothing to worry about. search srtforums.com, it will have all your answers. And if you do have an aftermarket wg, never go wot before 3k when cruising or else you get mad compressor surge.

Re: part throttle boost
 

a stupid small turbo would cause that, boost is either controlled by the pcm from a selenoid, or when you put an aftermarket wg on, you can run a line from the turbo directly to the wastegate and control it from a boostcontroller

Re: part throttle boost
 

how can any size turbo cause it?

he lifts to control airlow to the engine, the engine is still flowing a lot of air, just not as much as it was, wastegate hooked to manifold, wastegate sees pressure drop, and closes to correct it, raising boost on the cooler side of the throttle and thus increasing boost in the manifold again to what the wastegate target is.

its just the same as hooking it on one side of the cooler or the other.

if you have a perfectly accurate gate, and reference it from after the cooler, you will get that many psi exactly. if you reference it before the cooler, you will get that many psi THERE and something less (that many psi-cooler loss) on the other side. in the former case, the wastegate is correcting for cooler pressure loss, in our case, if its wired wrongly, its correcting for a partially closed throttle, aka restriction. just like a voltage reg correcting for loss in wires etc...

its not rocket science.

OP, please post and give us a verdict!