wastegate/mbc/whatever

[talontedEcLiPsE]

i have a 91 eclipse gs-t, and this guy had a 91 talon tsi. he said he capped off the vaccuum hose going from the turbo to the wastegate(stock setup), and said it added 2-3 lbs of boost. I told him that its dangerous, the boost could spike up too high because the wastegate wouldnt be opening. He said that "thats theoratically true, but the manufacterers wanted a safe and economical car, therefore they toned it down a little by putting a wastegate on it, a wastegate that wasnt really needed". so i went to home depot and bought an open/close shutoff valve and two 1/4" flanges for either end, to splice the vaccuum hose into. that way i could try it, if it looked too dangerous i could just leave it open, or i could even have a little type of boost controller. then i decided to ask u guys about it first. What do you think about this? Could i spice this shut-off valve into the wastegate vaccuum hose, shut it, and safely gain some extra boost? i still have the stock setup pretty much, as far as turbo, wastegate, and hoses, so what do you think?

[JoeWagon]

The wastegate IS needed because a 14b can flow a lot more air than a stock car can handle. I would have thought capping the boost source for a WGA would stop it rather than just adding a 'few psi' (Doesn't he have a boost gauge?).

Your valve is almost a basic boost controller, but not like an up to date style, so it might be interesting trying to adjust it just perfect. MBC's really aren't that expensive, but see how that works with your aftermarket boost gauge.

[96TSi]

that guy is a moron.. dont listen to him.

what you are doing though is a manual boost controller. it is safe for your turbo/engine as long as you have no leaks in what you put on. i made a MBC the same way on my Talon TSi AWD

remember, stock boost guages are inacurate.. go back to home depot and get a psi/kpa air pressure guage(a good one from there would be a 0-60psi guage). make sure you dont go over 16 or 17lbs of boost or you will tear up your components over time

hope my info can help, ask more questions if ya have em... its the only way to learn

*EDIT* we replied at the same time

[talontedEcLiPsE]

JoeWagon:
I would have thought capping the boost source for a WGA would stop it rather than just adding a 'few psi'


what exactly does wga mean, and how could that stop the boost?

anyways, if i did the mod, how could i safely check it out? i have an autometer 30boost/30vaccuum boost gauge, so i could monitor how high the boost gets. what should i do, drive around normally and see how it is, then get on the expressway and punch it a couple times and see how high it goes? I have 147000 miles on the car, how high of a psi level could my car handle?

i read this one post from dsmtuners.com(i think..?) about a DIY mbc, and he mentioned drilling a small hole into it to release pressure, but for some reason the hole doesnt hurt anything until the boost gets really high, or something like that, i asked him in an email a few months back, but dont remember what he said. If I could get up to like 14-15 psi, or more(im running 11-12 right now) that would be pretty good...watcha think?

[10.5sec92AWDTALON]

You need an aftermarket boost gauge, the stock one is a joke. Without the wastegate opening the 14b can boost well past 22 psi on a stock motor potentially doing a lot of damage.

The little valve you got will work fine, it won't be real precise but it will let you control boost, one thing.... don't remove any of the stock vacuum hoses for the wastegate, one already has a brass restrictor in it and you'll end up with less boost. The best cheap setup is a combo of a restrictor like you got and a bleed valve, between restricting and bleeding off the signal to the wastegate you can get good control for a dirt cheap price. I still use my $30 homemade setup on my 10.5 sec Talon, it's fully adjustable from the cockpit.


LOL...FWIW Years ago one of the first mods I did was to simply put a zip tie on the wastegate hose, I got an aftermarket boost gauge and played with the zip ties until I got a reasonably well controlled 18 psi of boost. Stock the car ran 14.8, with this zip tie and a K/N I ran a 14.4 with no other mods.

[96TSi]

WGA = wastegate actuator

how did you get a home made boost controller to the cockpit of the car without alot of inacuracy? thats a lotta hose for your vacuum to travel

[talontedEcLiPsE]

oh man oh man im gettin kinda psyched about watching the boost gauge go past "11 psi"...if thats possible.......oOoOOOeEEeeE!!!

this is how i blow all my paychecks, listen to one guy in a parking lot, then i come here and read posts and see pics of cars, now i wanna go out and buy a bunch of stuffand be running 10's by midnight, or bust.



thats what the guy who made the DIY MBC thing told me, that the little hole he drilled in it was a bleeder...this valve i got has enough room for a bleeder hole to be drilled in, ill take pics of it in a sec

[10.5sec92AWDTALON]

Originally Posted by 96TSi

WGA = wastegate actuator

how did you get a home made boost controller to the cockpit of the car without alot of inacuracy? thats a lotta hose for your vacuum to travel

Dual control. I have a small restrictor valve under the hood that I can set for a range of boost. The in the cockpit one is a bleed valve which comes after the restrictor one. I've used this setup for years now with many different turbos. When I had it on the 14b I could adjust from 12-22+ psi within 1.5 psi accuracy. It fits perfectly in the hole where the cig lighter was.

[96TSi]

oh, after 15psi you are just messing shit up under the hood. i wouldnt recommend it if you are barely over stock

[JoeWagon]

WGA Wastegate Actuator. The brass colored part that the hoses go to.

96tsi, yeah I took forever posting because I had to look at Kevin's RKO post to remember if capping boost source would increase or decrease boost (if the boost source opened or closed the WGA in essence).

The only reason that it might be harder to control boost is that the new MBC's are a different style. Ball and spring type valves effectively cap the boost source until a certain pressure is reached. Then the ball comes off of it's base and it let's the WG open yadda yadda, so it's precise as to when it opens. YOURS will restrict only a certain boost no matter how many PSI is being put through the valve. No biggie, like 10.5sec said, they still work.

Just get on the throttle and see how much boost you build while the valve is OPEN. Should be like 7psi or something low like that, can't remember 1g WGA spring pressure. Close the valve a little and go again, keep going until you reach the desired boost level. You are just restricting the boost like 10.5sec did with zipties back in the day. As to what boost to run on a 14b, I wouldn't know... I would have guessed 18 hits fuel cut.

[96TSi]

Originally Posted by 10.5sec92AWDTALON

Dual control. I have a small restrictor valve under the hood that I can set for a range of boost. The in the cockpit one is a bleed valve which comes after the restrictor one. I've used this setup for years now with many different turbos. When I had it on the 14b I could adjust from 12-22+ psi within 1.5 psi accuracy. It fits perfectly in the hole where the cig lighter was.

damn thats a good idea. talk about saving some effort and money

all it takes is a poor man and a little thought to come up with the best cheap mods

[10.5sec92AWDTALON]

Originally Posted by 96TSi

oh, after 15psi you are just messing shit up under the hood. i wouldnt recommend it if you are barely over stock

If you run 93-94 octane gas 17-18 is safe long term on a 1G. The stock F/P & injectors can easily handle that on a mildly modded stock turbo setup.

[96TSi]

oh no man, the "that guy is a moron" wasnt referring to you, i was referring to to talontedEcLiPsE's friend in his post

heh i put an edit at the bottom of mine after i realized i wasnt the first reply to him

[10.5sec92AWDTALON]

Originally Posted by JoeWagon

. As to what boost to run on a 14b, I wouldn't know... I would have guessed 18 hits fuel cut.

Depending on the car and temp outside, yeah around 18 you might hit it. Take the lower honeycomb out of the MAF and cut the divider wall out of the lower oval portion and you'll push fuel cut past 21 psi on most 14b cars.

[talontedEcLiPsE]