getting top end back

[crash27578]

I put a evo III manifold and external wastegate and I gained a little low end but I feel I lost top end. What is the best way to get top end back?

 

[Streetbeat]

you should of gained more top end with a higher flowin exhaust manifold.

 

[crash27578]

The turbo end is not ported so I think thats why.

 

[bjgarvin]

you don't have a turbo listed in your mod list. please tell me you don't still have the t25 with an external WG.

I'm afraid to ask what boost controller you are using.

Ben

 

[GaRn]

prolly the difference in low end power made your butt think you didnt gain any high end!! that manifold results in quicker spoolup id assume.

 

[Agent Ezzard]

I know why you lost your top end. It is because you are using an external gate with a T25. Reason: Your lack of boost creep. Since you put an external gate on you car with a T25, the small amounts of creep that were present with the internal, are absent with the external therefore KILLING your tiny turbo's attempt to main your preset boost. Just take a look at your boost gauge. Before it was probably around 10-11 psi at redline now it is probably around 9-10psi. Trust me, I had an external dump and it netted the same results. Externals are meant for higher flowing turbos.

 

[crash27578]

I do still have the t25 (I hate it)and the reason I got the external dump is because my wastegate was screwed on it and I don't have the upgrades for a bigger turbo right now so I went with the external dump to have one step closer to holding a 16g. This is why I have a external dump on the piece of shit t25. As far as the boost level I was pushing about 17\18psi where the wastegate was messed up and now I'm pushing 14 because that is what the tial spring is set at. I got to thinking about this and this is why I feel lost top end, the whole boost creep by Agent Ezzard so he was right. I had a homeade boost controller set at 17psi but the engine heat screwed the spring up and made it frezze where it wouldn't open. A boost controller is going to be my next purchase.

 

[Agent Ezzard]

A boost controller won't help. I say use the External Dump as an excuse to get a Big16G or something larger. I sold my external dump to TWITCH and he was so happy to have it that I am not sure he noticed the decline of performance with the T25.

 

[nine5raptor]

when was this, because twitch has been running a b16g for a while now.

 

[L2RTSiAWD]

Ya the T-25 has crappy top-end to begin with then you throw an external gate on there. I would say also it's time for a better turbo.

 

[Agent Ezzard]

Originally posted by nine5raptor
when was this, because twitch has been running a b16g for a while now.

Back when he had a T25

 

[crash27578]

Why would a boost controler not help. 3 more psi so roughly 15-20 more hp. I know the turbo falls at about 5 grand but it will still help 3-5rpm range. Why would the external dump hurt my power? Is it not having boost creep anymore? And as I said in the other post I do plan on a 16g this spring and the external dump was just one step closer to running it the right way. Also how important would getting a better intercooler right now before the new turbo or would it be ok to get the turbo in the spring and work on getting a fmic in the summer?

 

[Agent Ezzard]

As soon as that wastegate opens, the power is gone.

 

[nine5raptor]

Originally posted by Agent Ezzard
As soon as that wastegate opens, the power is gone.

Actually, when he is in the range he is talking about, the wastegate isn't even open (there isn't enough pressure to overcome the spring).

Crash-- what kind of dowpipe/catconverter are you using? Based on what you said, I am thinking that those 2 are smaller in diameter than your 02 housing which leads to extreme turbulance in your exhaust stream (when it hits the sharp 90* neckdown). If this is the case, it is actually more restrictive than the stock setup with a smoother flow (even though the stock 02 housing was smaller).

 

[crash27578]

My o2 housing, downpipe, and cat are stock. My manifold on the other hand is a ported Evo III which is about 3\4" bigger than the turbo exhaut inlet. This is why I put I might need to just take a dremial tool and at least round the edges. My external wastegate is on my manifold not my o2 housing. I could be wrong but the only place I think I should have turbulance is where the manifold and turbo meet. Correct me if I'm wrong. Also I hit full 14psi at about 3300rpm so thats when the dump opens. I do notice without boost creep the car dosen't keep pulling as much but I feel safer not peaking at 24psi before the t25 wastegate would open. I'm not regretting the external dump on the t25 simply because it will be better on me in the long run when I get the 16g that I want which might actualy be really soon.