I will now show how little I know about turbos, so please go easy on the newbie.

I've just made a very simple hybrid turbo using 2x RHF3's the original on the car (660cc petrol/gasoline) was a VQ32 which was well worn and not holding good boost. I picked up a cheap (99p ebay ) RHF3 VIBG off a 1500cc diesel and have combined the two.

I've used the exhaust housing, turbine and spindle from the original VQ32 (so the flanges matched up) and the CHRA, compressor wheel, housing and actuator for the slightly bigger VIBG.
I'm in the process of modifying the oil, water and intercooler pipes, and am hoping to have it running by the weekend.

Any thoughts on what the larger compressor side and actuator will do to performance, spool up time? I've added a bleed valve so I can regulate boost pressure and I'll be praying alot when I start the car for the first time.
The stock turbo on the car ran at 0.8bar (12psi) and the one from the diesel ran at 0.5bar (7psi).

I've done this as it was the simplest way I could get the turbo repaired and hopefully running smoothly on the car as spares for the stock turbo are unavailable in the UK.
I'm not expecting much knowledge on these turbos as they're very small and not used much outside of Japan, but any thoughts/comments appreciated.

Chris

 

Turbo installed and currently seems to be working fine. Theres a bit more lag than the old turbo, but it kicks in nicely at about 4.5k. This may seem high, but these little engines rev to 9k without issue. I checked the figures on the IHI website and the old compressor had an AR of 7 and the new one 14 ... so double the capacity unless I'm mis-reading something. ihi figures ... I've gone from a VQ32 compressor/housing to VIBG and kept the VQ32 hot side.

As said previously I fitted a bleed valve to regulate pressure and currently have it screwed in all the way so its just boosting at 0.5bar (7psi). My intentions are to run it like this for a week or so and then increase the boost slightly, prob to 0.7/0.8bar (10-12psi).

Is there a general rule for running in a new turbo or not? Does what I'm planning seem sensible or should I more/less conservative with the boost increase?

Chris

 

Did you get it balanced?

 

No.
The only place locally that could do it wouldn't ..... They will only do full rebuilds for £200, even though they wouldn't rebuild my turbo, they'd never heard of an RHF3 VQ32 before, no joke.

After reading on here I didn't think getting it balanced was too important as I hadn't altered any of the fins on the turbines. I basically just swapped over some parts between turbos.