Disco Potato=T3/T4???

[cosmo]

I am looking to build a T3/T4 turbo that will have comparable response to the disco potato (Jason Kavanaugh claims 12psi at 2900 rpm in a 1.8 Miata) but with more flow. (DP maxes at about 320, I want about 350-375)

Plus the DP costs about 1100$ and I figure I could get a hybrid for 6-800.

Little Help?

[WDRacing]

I'm sure C-Kwik and Demcj will have an opinion on this matter, they're the compressor map guys. But in my thinking, your not gonna gonna get a non ball bearing turbo to boost 12 psi by 2900 and still have enough efficiency to produce 350-375hp.

If your looking for a good hybrid, try the T3/TO4E 50 trim .63 EX AR with the stg 3 wheel. After having many debates and looking at alot of compressor maps, that combo seems to be the current champ in the hybrid community.

Just my .02WD

[cosmo]

I was gonna get ball bearings though

[C-Kwik]

The Disco Potato is very responsive because of it's size. Both the turbine and the compressor fit within a housing whose outer dimensions are similar to a stock T25 on the SR. This combiones with such a high efficiency for such a small turbo makes it a great turbo for moderate boost. But it's peak flow is a lot lower than a T04E, but if you are working within a limited boost range, it works fine. Chances are you are not going to get the same response with a T3/T4. The T3/T4 has a larger compressor and turbine wheel, which means it requires more air to drive the turbine, and it has more mass to move around. The T3/T4 is still quite responsive. You can try using one of the smaller turbine wheels coupled with a lower A/R, but if you have a goal of 350 HP+, a small turbine will be like "chasing one's own tail". You can't have your cake and eat it too. Some compromises will need to be made.

As far as cost, a ball bearing T3/T4 will usually be higher than $6-700. It might even be nearly as much as a DP.

Also, keep in mind the Miata is a smaller motor and puts out less exhaust energy for a given RPM. The DP would spool up very quickly on a KA.

My opinion is that you won't be dissatisfied with the response of a T3/T4. Especially with a BB center section. I've driven one before and while it wasn't instant on/off boost, it certainly was spooling quickly. And this considering I run a straight T04B and I'm happy with the response of it.

[cosmo]

So what WD recommended sounds good?

[C-Kwik]

It should be a good match. The compressor is a great match for the KA and frankly, with a lot of 4 cylinder motors. That turbine should provide great response without being a severe restriction. I personally would use a T4 turbine myself, but I don't put a huge emphasis on response or boost threshold. I don't need boost until I'm over 4000 RPM anyways. I'm probably never below 4000 RPM at the race track. And I don't mind downshifting....ever.

But yes, that turbo would be a good match for what you are looking for. And it the compressor should give you a ton of headroom for more boost later.

[WDRacing]

For the record, C-kwik showed me the compressor map for that turbo. I just tell everyone about it...heh.

[cosmo]

thanks guys

[andrave]

it won't ever be as efficient as the "disco potato" because the T wheels used outdated compressor aerodynamics. Its more than bearings or size, its the design of the turbocharger. Garrett makes larger turbos with modern dynamics, the GT series, and they are really ****in expensive.

[C-Kwik]

The T04E-50 has a peak efficiency island of 78%. That's right up there with the GT series compressors and actually surpassing some of them. And the T04E-50 is much cheaper than a GT turbo. And the disco potato has a peak efficiency island of 77%, and the shape is narrower and shorter and would be at a lower point on the rev band of a KA at 15 psi. The GT turbine will probably be a little better, but I wouldn't an huge gain there. For it's size the DP is a great turbo though. It still has it's limitations as does any turbo.

[Projex240]

I dont think there is any benefit for the gt series turbos other than they are all dual ball bearing I believe. They have a great design for their ballistic turbine housings which bolt the external wastegate directly to the turbine housing. The dual ball bearing center sections allow for a larger turbine housing to be used without any sacrifice in lag time. These new wheels arent all the greatest improvement, but they do make good power increases over the t series wheels. I dont think theres any reason to use a gt over the "t" other than you have alot of money and want only the best turbo for your car. IN that case--go with a turbonetics or a HKS unit.