My new Modified CT12b Turbo’s are Installed! by Stu Hagen

3 minute(s) of a 11 minute read

As far as the "limit"? Well, I think going with a JDM sized turbine will be the limit. I wouldn't want to go much farther. Why? Well, as it stands now, I think I am reaching the limits of the stock system in general. Like actuators, VSV's, etc. I have had many conversations with people like TomSid who had gone to modified turbos that were larger, and they had problems with this stuff. I have also reached the limit as to compressor wheel. Any larger and you risk weakening the housing themselves. Your also limited on the turbine side because of the exhaust housing. How much more HP with the larger turbine? Not sure. Maybe another 10HP. Once you do that, you now reach the limit of the exhaust manifold's ability to push out the increased air. The exhaust manifold flow tested at 57, and we are getting close to that now. Beleive it or not, the manifold is not the weakest link, it is the turbo's themsleves.

Also, keep in mind, this is all based on maintaining sequential. This has nothing to do with TTC. The limits on that are higher. Its all about keeping the OEM sequential operation. Again, these graphs DO NOT show justice in the low end because of the malfunctioning #1 turbo valve that I overlooked. This will be re-dynoed very shortly to show this.

As I mentioned, I feel that the overall increase in HP and TQ will be about 10%. This is for whatever level of BPU you have. If your stock, + intake, cat back, and no DP, it might be a little less because of you inability to not control higher boost. With a boost controller, then I will say 8-10% is fair estimate.

Please do not ask me costs and or pricing on this. This is a "beta" testing thing for me with another Supra owner/engineer. In the future if this has any interest with other people, I may become a sponsor. I want to maintain respect here and not go beyond my limits as an enthusiest, yet a non-sponsor.

6-13-2007

Just to continue my results.

Today, I did a road course event with a fellow SF member. I thrashed my turbos as best I could lol~. I ran in TTC all day. I couldnt get any lower that 18.7 psi with my controller pretty much turned off. On the other hand, I never went over 20psi.

So they held up well, survived the dredded turbo backlash from TB Lift. Road races would understand that.

Stu

We have been waiting VERY patiently for others to post there results. The only results we have so far isnt really what we are looking for (Hi Boost heavy mods)

We will hopefully have results from a prominent member here is his BPU++ car.