SC300T

I thought you were basing your opinion on something other than "I have not seen anyone on SF reach the 500rwhp mark on less than 20psi and a small turbo". I was under the impression that you ran some calculations following some compressor map or equivalent.

As a general observation, the general system on SupraForums running a small turbo has:
8.5:1 compression (more turbo, less engine)
Little or no porting/polishing of the head
No rev limit increase
Stock cam
No standalone ECU with wideband 02.

I'm hoping that keeping the compression high will reduce the load on the turbo.

Essentially I'm making the engine's compression do more work, the turbo less work. Increasing the RPM will directly increase RWHP as far as the engine's natural contribution is concerned, even though RPM won't necessarily make much more RWHP via the turbo's boost. The cam, porting, etc. accentuates this. (or at least should). The cam that is currently in the car is ideal up to around 8500rpm at the expense of 3000rpm midrange torque.

14psi at 8500rpm is still very close to the top efficiency of the T60-1 (at least according to my numbers). The T60-1 isn't so good above 16psi, but if you look at the map, it seems to be very able to handle increased flow moving data points to the right (through higher rpm.) On this engine, 6500rpm seems dead middle the efficiency range, 8500 rpm is on the outer side near the first ring of efficiency (still 74%, though).

SC300T

If anyone has any numbers that suggest this won't work, please let me know. I know this is the road less traveled, but it should yield a quick street car with lots of off-boost power (10:1) combined with small turbo (quick spool with full boost by 3krpm if not sooner) combined with big cam (High rpm power up to 8500rpm).

motorheaddown

Scott,

You're absolutely right. This is the road *less* traveled. I don't know of anyone running 10:1 at 8500 rpm and 14 lbs of boost. Do you think you'll need stronger rods to keep the motor together? What about crank balance at that high of rpm. Again, I conceded that you're trying to get to 550 rwhp on rpm and not boost. On boost alone at 7500rpm, you're going to have to run 20+psi. But that's the road that *is* traveled.

Maybe you're right. It'll be interesting to see your dyno numbers when it's complete.

-scott

motorheaddown

Scott,

I do have a question off topic. Are you using the Toyomoto cast iron manifold? If so, did it come with a wedge between the t4 flange and the turbine housing to help the compressor inlet clear the distributor?

Thanks,
-scott

SC300T

I have no idea about any crank issues that may (or may not) arise. Titan runs 9000-9500rpm on the same crank. I imagine they are balancing the rotating assembly to a close tolerance. That said, Lexus touted internal component balancing for the virtue of vibration reduction, so who knows.

Alot of the T04R board members spin up to 8500rpm on the stock bottom end. At 500-550rwhp, the cylinder pressures aren't great enough to really stress the pistons or rods too bad. Supposedly the main issue with 8500rpm is preventing valve float and using a cam that has enough lift to allow the engine to breathe up there.

On the other issue, yes, it is a Toyomoto Manifold. There is a wedge between the manifold and the turbo assembly. Its a custom iron part with gaskets on both ends. It is around 1/2" thick.

Lance has said that a "full" T67 could be squeezed in there and still maintain enough clearance.

motorheaddown

Thanks!

Well, it seems you have a beat on running high rpms.... I hope you didn't find my questions offensive, and I look forward to learning more about your approach.

I also would like to exchange data on our setups. I received my Toyomoto shipment today and will probably have some questions about installation if I can't get a hold of Lance.

Thanks again!
-scott

SC300T

If you need any install help, don't hesitate to ask me. What stuff did you get? There are some tricks to installing the turbo bits. If you put them on in a certain order, it goes much smoother. Let me know what you've got and I'll try to give you a heads up on individual steps. If you'd like, e-mail me scott@datapathusa.com for the fastest response. I'm virtually always on-line but not always on the CL board. I also have a ton more pictures from the assembly procedure that I just did, starting with the head removed, so if you need any pics of steps, let me know - I'll e-mail them to you.