Erich

Supposedly 500 rwhp is the upper safe limit. I know some people running more but also have seen some split blocks at higher levels. This motor is not going to rev that much (below 6000) so that may help a bit.
Erich

2tonehatch

holy crap. i love it.

nonvtec

Gosh the power drops off early. I was under the impression 5.0's could rev and were revved higher than that but I dont see why you would. That is a ridiculous amount of torque, well done.

HiProfile

That thing's dyno chart looks like a teenager having sex - reaches its peak prematurely, and don't last long.

J/k, must be crazy on the street. 2x the torque of built b18's for most of the powerband. Eat any good cars on the road lately? Bet they didn't expect it.

St.Taint

I have a couple HT12 (FC3S) wheels that I could throw on those shafts. The only thing is that I'd need the center cartridge, compressor housings, and turbines. The T Bird wheels measure 52.5mm outter diameter and 39 mm inner diameter. Each HT12 measures 57mm outter and 42mm inner. The difference in turbine shaft is .25 mm so I'd have to mill the compressor wheel to accept the RHB5 shaft then throw the center cratridge on a lathe to to take a few mm from the outter perimeter of the seal plate. Mathematcially it works out to be around a 30% difference per each compressor wheel, so you'd have much more power at the same if not lower boost levels. If you want more consistancy with those turbos, drill a small hole in the actuator that attaches to the flapper. Then drill another hole on the wastegate diaphragm plate. You'll need a spring or two to experiement with and an small air pump for find out which spring works best. The stock spring rate on those is 8.7 psi, so anythign above that and the pressure wills tart to force the valve open thereby dumping your boost when you need it most, higher rpm. You can use the air pump to figure out when, where, and how long each different spring is changing the spring rate in the diaphragm itself. It's a homebrew way to fix an otherwise shitty wastegate. Or just swap a few T3 actuators behind there and make sure the rods line up. The T3 are 14 psi for the most part. The RHb5 gates have a max of 14 psi, meanign they should never see higher than that or else they'lls tart to wear prematurely. This is straight from the Mazda and Ford workshop manual.

Erich

Wow-extremely interesting. I really like the idea of having modified IHIs that perform at a higher level. I always heard there was nothing that could be done for these turbos. Currently, I will probably leave the turbos on there tho. It has taken a while to get to this point and I want to get some racing in as is but you never know, I may take you up on it. The wastegate idea is less invasive for sure I would be more likely to try that at this time.
Erich

Erich

Now, I'm really curious. Would this compressor wheel swap make the IHI equivalent to the bigger Tbird .63/.60 t3s? Actually, I never really got a good feel about how the IHIs compare to the smaller 0.48 Tbird T3s. It would be nice to flow more air higher up in the rpm range. They do die off fast.
Erich

normality78

simple setup, great numbers. cooll....

St.Taint

Here is the stock Warner Ishi wheel on the center cartridge:


I'd have to remove the outter perimeter by the seal plate:



This is using an RHB6 57mm wheel for reference:


See how it would rub?



Here is a 57mm wheel back to back with a 52.5mm RHB5 VC32 (T Bird) wheel


Here is the actual HT12 wheel:






And here's the HT12 wheel in a T Bird housing:



T Bird wheel = 52.5mm outter and 39mm inner, HT12 wheel measures 57mm outter and 40mm inner.

It's an interesting swap indeed but for your power and engine, I'd probably just go with a few standard T3's. Either 60 trim compressor (T3 Turbocoupe) with a .48 A/R exhaust side or .63 if you were going for max power.

Here is somewhat of a compressor map:


Hitachi doesn't publish their specs. Unfortunately you can only guesstimate using the RX7 hp vs boost pressure. Each compressor wheel with standard turbine (which is almost exactly the same size as the RHb5 turbine that you have) is good for airflow in the 220 hp range on average 14-16 psi boost pressure. This same VJ11/HT12 hybrid was used on a 2.2 sohc engine making 230 hp on 10 psi. Even so, I'd look for actual Garrett T3's. I have two brand new genuine Garrett To4B S trims but they have dual volute T4 exhaust housings. Guaranteed Garrett and will come shipped in a Garrett box but the exhaust housigns won't fit your manifold unless you go to the standard t3 5 bolt and have it ported to accept a Stage 3 (standard T4) turbine.