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-   -   Wastegate spring? (https://www.rx7club.com/single-turbo-rx-7s-23/wastegate-spring-408878/)

XSTransAm 03-27-05 09:49 PM

Wastegate spring?
 
im running a 5.7psi spring on my hks standard wastegate. Ive got the car running up to around 14.5 psi using a ball spring boost controller, but i just cant seem to get it to run any higer. That and I cant hit anywhere near 14.5 in first or second gears.

has anyone else expierenced this running a similar spring? Im about to buy a 10psi spring, but i hate to throw another 30$ on something like that if its not going to help.

Thanks, Mike

oh and a side question, what has anyone used to block off the stock coolant lines to the turbo, I used a quick fix when I put it together(you dont even want to know), but i want to do something more perminant now that i have the time.

bcty 03-27-05 10:17 PM

a few good solid rubber caps and clamps could blockoff the coolant lines

and a 10psi spring should help you
i am running a 8psi spring in my HKS wastegate 15psi no problems..

what boost contrller are you useing?

Sir Rupert Hobo 03-27-05 11:16 PM

i am NOT sure about the fd turbo coolant passages, but on my 13bt i just used a thick rubber cap on the water pump nipple. fill the cap with black sealant, let it dry and clamp it down.

for the water feed, i just used a block off plate meant for the split air valve with some gasket sealer. not sure if the FD's have the same sized outlet for the turbo feed as the SAV though.

Carl Byck 03-27-05 11:24 PM

On the spring, YES that is what you need. Will you please measure the free length of each spring, and PM me as well? Thank, Carl. BTW An EBC will, make a huge difference over the MBC in terms of response, and holding boost. It will not fix the spring issue though. Rule of thumb is 2.5X the spring rate= max boost. Carl

RETed 03-28-05 06:21 AM

Run a stiffer spring.
I would normally run only 100% above the WG spring rate with a boost control, therefore, your ~6psi spring is only good for 12psi of molested boost.
Running too high on a soft spring causes the WG to oscillate and do weird things like not make more boost.

With the 10psi, you can go up to 20psi no problem.


-Ted

XSTransAm 03-28-05 08:21 AM

thanks guys, I was using a standard bleeder valve (turboxsa), but could only get like 13 psi with that, Then i switched to a ball and spring (turboxs) and the lag decreased about 500 rpms and boost up to 14.5 but thats about all.

For the coolant nipples i used rubber caps that i got in a vaccuum hose cap kit that fit the nipples. Im just worried that since they arent heater hose (dont have the fabric woven in) that they will eventually burst with the heat on and off.

ill go ahead and order the new spring and let you guys know how it goes. and ill try and measure the springs and send you the info carl.

Thanks again, Mike

pistonsuk 03-28-05 09:55 AM

block off the stock coolant lines to the turbo,
 
i used an n/a rear rotor housing (not because of this but it helps) when building the motor. this doesnt allow the coolant to even flow into the lower intake. maybe you could plug that hole between the lower intake and rear housing w/ jb or a steel plate/rubber washer combo.

i cut off the steel nipple and then drilled and 1/4"NPT tapped the wp housing. i got a plug from home depot plumbing section.


justin

pistonsuk 03-28-05 09:57 AM

oops
 
i just realized you have an FD...

take that info for whats its worth

justin

Howard Coleman 03-28-05 10:12 AM

mike raises, IMO, an important question.

many of us have blocked coolant from our throttle bodies. in most cases we have simply put a rubber cap over the two tubes ( top of the rear iron and water pump) and considered it handled.

if either of the rubber caps fail it is Blown Motor in less than 30 seconds.

so we are betting our motors that some crummy 2 bit rubber cap from autozone will hold.

not a good bet, but one most of us make.

i had the rubber hose from the driver's side of the rear iron to the heater element fail while on the expressway. by the time i smelled coolant and immediately pulled over and shut off the engine i had lost the rear rotor.

if either of those caps fail it is good by motor.

i am putting my motor together this week and on my short list will be to cut off the pipes, drill and tap 1/4 pipe.

i just don't want to make that bad bet, as it is not if the rubber cap fails but when.

howard coleman

Carl Byck 03-28-05 10:22 AM

IF, IF, IF, you are going to capoff coolant lines, the safest way to "cap" them is with a reinforced rubber hose of the corect size, hose clamped to the nipple. Then, leave enough material to thread a coarse thread bolt into the hose. Coat the bolt threads with a high temp silicone intended to stick to rubber, and hose clamp that as well. I have used this on turbo race cars for years(more than ten) with-out a failure. This leaves you with the stock nipples, and is as such reversible. Carl

Carl Byck 03-28-05 10:23 AM

BTW, 100% would be 2 times the rate of the spring, and in retrospect(perish the thought;) ) I agree with Ted:D

RETed 03-29-05 06:00 AM

Best method for blocking coolant fittings - pull the fittings, drill and tap, and insert plug OR weld over if you know a good welder.

I normally fill the fitting with silicone RTV and then cap with a rubber plug.
The RTV will flex with temps, and it's better than alternative epoxy or JB Weld.
No failures on any of my customers cars with this method...yet.


-Ted

maxcooper 03-29-05 06:14 AM

I had some un-siliconed rubber caps that I used for AST delete both pop within a month of installation on my car. I've been running hoses with a bolt in the end for the 5 years since with no issues.

I don't trust the caps anymore, even though it sounds like they can work with the silicone treatment. I have one of the nipples tapped and pipe plugged now, but there's one of those caps over the nipple (the plug is screwed down inside the nipple with seleant on it). It still makes me nervous every time I look at it, even though I know it isn't going to pop or leak.

-Max

ghostrx7 03-29-05 06:39 AM

I have a piece of hose clamped at the nipple, bolt in the other end, which was clamped as well. So far so good after a few months...I wouldnt trust a cap, personally.

technonovice 04-01-05 04:06 PM

Am I missing something.Why would you cap it?

All you have to do is re-route the hose that formerly went to the top of the throttle body to the fitting underneath the throttle body. The hose seems almost made for it. It reaches and clears just fine.

I reailze that it does not eliminate as much, but it does keep a little bit more coolant in the system. 20 ozs?

XSTransAm 04-02-05 01:26 PM


Originally Posted by technonovice
Am I missing something.Why would you cap it?

All you have to do is re-route the hose that formerly went to the top of the throttle body to the fitting underneath the throttle body. The hose seems almost made for it. It reaches and clears just fine.

I reailze that it does not eliminate as much, but it does keep a little bit more coolant in the system. 20 ozs?


i was more talking about the lines that goto the stock turbochargers

BATMAN 04-05-05 01:47 PM

hey woah where did you get your spring from..
i just recently ordered and installed my single T-78, and the wastegate didnt come with a spring so.. it sorta left me hanging, i need to order one but im kinda clueless as to where. if it means anything it a Greddy kit

XSTransAm 04-05-05 08:40 PM

search www.froogle.com for "greddy wastegate spring" you can find them for around 30$

(im really suprised your kit didnt come with a spring though)

GARCO MOTORWORKS 04-06-05 07:12 AM

To block the water hose nipples on my car and my customers cars I pull out the steel nipples and drill and tap the hole in the rear iron .The water thermostat housing hole gets welded up and smoothed out . No failures to date .

XSTransAm 05-13-05 02:09 PM

so one of those rubber caps burst on me today, luckily i noticed the car getting hot and parked it before anything bad happened. went to the auto store.. bought a new vacuum cap and replaced. lol (dont worry im going to do something perminant in the next week)

they lasted about 5,000 miles on the engine.

also i put the 10psi spring in my car yesterday, spool up improved greatly and its boosting 15psi no problem!

Sesshoumaru 05-13-05 03:23 PM

I always just route a hose from in back of the wp to the rear iron.

With an FD it's really nice b/c of the room under the manifold when it's simplified. FC's can do that too just a little more crowded.

dubulup 05-15-05 09:26 AM

where don't you loop the return and feed coolant lines with a coolant hose.

vacuum caps will fail...

XSTransAm 05-15-05 11:20 AM

thats exactly what i plan on doing.

rzograbian 05-16-05 03:41 AM

ummm... i have done the bolt in the hose trick with the silicone just like Max did but when i installed my single turbo, i did something different... i looped the nipples for the coolant back into each other... that seems to be holding... and i have placed bolts in some rubber lines but i have extended those and tied them to something outside the engine so i can see them without having to take out the manifold if they are indeed leaking.. also, it might not look as good but its easier to change the bolt or replace the clamp when its easy to get to... my.02

-Roman

tk5dan 05-16-05 02:03 PM

yes go with the 10psi spring for sure. With the spring you have now you won't be able to reliably reach you goal of 15psi. Also with the increase in spring pressure the car wont be as loud for daily driving under partial boost situations and the turbo will spool slightly quicker because the gate isnt letting all the exhaust out before the turbo is spooled.


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