Honda / Acura K20a K24a Engine Forum banner

1 - 20 of 27 Posts

·
Registered
Joined
·
671 Posts
Discussion Starter #1
Need to hear your spring rate recommendations for my tial wastegate. I have heard different recommendations like "generally the spring rate will support up to twice its natural rate." I've also heard some say that with a boost controller they can turn the boost up to well beyond twice the spring rate. If this is the case, am I right in thinking I should get the smallest, .2bar, spring for the most control? Your thoughts?
 

·
Registered
Joined
·
2,735 Posts
wut are u trying to boost it to? psi wise? i think thats a pretty important thing to realize before buying something beyond wut u need.
 

·
Registered
Joined
·
3,092 Posts
Typically you can boost up to twice the spring rate, more than 2X may maximize spring and you will need to step up to a bigger spring.
 

·
Registered
Joined
·
671 Posts
Discussion Starter #6
wut are u trying to boost it to? psi wise? i think thats a pretty important thing to realize before buying something beyond wut u need.
Well, I think I'll be maxing around 14psi, I'm not too sure though because I'm trying a turbo that nobody has really tried. (gt2871r) I would like to boost by gear and I know that 1st and 2nd do not need more than 5psi on street tires. I'm thinking 3-5psi would be good for 1st and with a .5bar spring that just would not be possible.
 

·
Registered
Joined
·
962 Posts
There are many considerations that you should look at when determining your WG spring pressure:

1. what type of manifold are you running?? If you are running a log style manifold you will run a larger spring to run the same boost as an equal length/sidemount setup. The high flowing, low restriction design of the equal length manifolds coupled with a gate not ideally located in the stream of exhaust gasses will cause boost creep.

2. what are your power goals???

3. what turbo are you running???

4. what is the minimum amount of boost that you are looking to run???

5. which wastegate and size are you running???

6. what sized downpipe and exhaust are your running???



For example,

I am running a peakboost kit with a gt3076, its an equal length design, little restriction, 3" down pipe & exhaust, Tial 44mm wg

I am running a 4.3psi spring and I am not able to keep the boost down much lower than 10psi with that spring. I am running 15psi on it with a GM boost control solenoid under full boost and it holds the boost steady and I know I can pump up the boost way more without having problems. I am running well over 2times the amount of boost that the spring is rated for but the design of the kit is what causes me to run such high boost with a low spring pressure.

If you are running something like a revhard kit with a 2.5" DP & exhaust then if you put a 4.3psi spring in it you can run 4.3 psi. You should try to keep it to where with a log manifold that you keep to 2-3 times the spring rate for maximum amount of boost you want to run, anything more than that and I would step up in spring size.

The more restrictive the exhaust and manifold, the higher spring rate you should go with.

I hope that made sense to you.
 

·
Premium Member
Joined
·
10,420 Posts
yea, you may want to look into another waste gate or a bigger one. im running a top mount tubular manifold, .7 bar spring and i creep to 12 psi.
 

·
Registered
Joined
·
671 Posts
Discussion Starter #9
There are many considerations that you should look at when determining your WG spring pressure:

1. what type of manifold are you running?? If you are running a log style manifold you will run a larger spring to run the same boost as an equal length/sidemount setup. The high flowing, low restriction design of the equal length manifolds coupled with a gate not ideally located in the stream of exhaust gasses will cause boost creep.

Custom tubular manifold-ramhorn style

2. what are your power goals???

400whp on my k24a2

3. what turbo are you running???

gt2871r

4. what is the minimum amount of boost that you are looking to run???

3psi......if possible What I really want is full control of boost by gear. If I'm burning the tires at 5psi in 1st, then I want to be able to turn it down a little. The reality of it might be that boost creep will get me, but I would like to have as much control of it as possible.

5. which wastegate and size are you running???

Tial 44mm

6. what sized downpipe and exhaust are your running???

3" dp- straight through exhaust


One thing that we might be overlooking is the placement of the wastegate and how it T's off of the manifold. If you are creeping above what you're spring is rated at, isn't that just a reflection of poor manifold design and/or wg size?
 

·
Registered
Joined
·
2,735 Posts
stick with a small size so that u can run low boost in 1st and 2nd, 5psi is good or even 7psi. 3psi you wont feel sh*t. u dont reach full boost until past vtec. i think u might need a bit more then 14psi on that turbo to get 400 whp. 14psi i believe you'll be at mid to high 300's.
 

·
Registered
Joined
·
671 Posts
Discussion Starter #12
stick with a small size so that u can run low boost in 1st and 2nd, 5psi is good or even 7psi. 3psi you wont feel sh*t. u dont reach full boost until past vtec. i think u might need a bit more then 14psi on that turbo to get 400 whp. 14psi i believe you'll be at mid to high 300's.
I think you're right, I'm kind of on untested grounds with this turbo. So do you think I should go .2bar? Do you think it will support up to 14+psi?
 

·
Registered
Joined
·
962 Posts
There are many considerations that you should look at when determining your WG spring pressure:

1. what type of manifold are you running?? If you are running a log style manifold you will run a larger spring to run the same boost as an equal length/sidemount setup. The high flowing, low restriction design of the equal length manifolds coupled with a gate not ideally located in the stream of exhaust gasses will cause boost creep.

Custom tubular manifold-ramhorn style

2. what are your power goals???

400whp on my k24a2

3. what turbo are you running???

gt2871r

4. what is the minimum amount of boost that you are looking to run???

3psi......if possible What I really want is full control of boost by gear. If I'm burning the tires at 5psi in 1st, then I want to be able to turn it down a little. The reality of it might be that boost creep will get me, but I would like to have as much control of it as possible.

5. which wastegate and size are you running???

Tial 44mm

6. what sized downpipe and exhaust are your running???

3" dp- straight through exhaust


One thing that we might be overlooking is the placement of the wastegate and how it T's off of the manifold. If you are creeping above what you're spring is rated at, isn't that just a reflection of poor manifold design and/or wg size?


stick with a small size so that u can run low boost in 1st and 2nd, 5psi is good or even 7psi. 3psi you wont feel sh*t. u dont reach full boost until past vtec. i think u might need a bit more then 14psi on that turbo to get 400 whp. 14psi i believe you'll be at mid to high 300's.
I am pretty certain with a boosted K-series (even with a setup as small as a greddy kit or a super charger) you will not have traction in first gear ever under boost. hell, I had traction problems in first naturally aspirated.

With these cars boosted running in excess of 400+whp there is going to be a sever lack of traction on the streets. Now, on slicks at the track you will not have to worry about the traction issues.

Why run such a small turbo on a k24??? that thing is going to be at full spool at about 2500 RPMs, lol

If you want to run low boost you won't be able to run anything lower than a 2.3psi spring. I suggest you try that and you may be able to keep the boost down to about 5psi or so
 

·
Registered
Joined
·
748 Posts
As in the 38mm one functions the same(line from boost controler goes on top and the direct vaccum source goes into the side) and the vaccum diagram will allow my wg and boost controler to work properly. I know I am usinrg a different boost control solenoid, and will have to take that into account. Sorry for the confusing question...
 

·
Registered
Joined
·
962 Posts
As in the 38mm one functions the same(line from boost controler goes on top and the direct vaccum source goes into the side) and the vaccum diagram will allow my wg and boost controler to work properly. I know I am usinrg a different boost control solenoid, and will have to take that into account. Sorry for the confusing question...
I think that you are in the wrong thread asking that question, lol. I think that you are talking about this diagram I made yesterday and posted in another thread on the tial 44mm WG



But yes, you plumb in the wastegates the same. This diagram should work with most wastegates. Its quite simple actually
 
1 - 20 of 27 Posts
Top