[krisr]

Originally Posted by 242177P

Tom critiques turbo. Doesn't recommend one
Krisr recommends one he personally used
YoU'rE nOt eVeN aN EnGiNeeR!!!

Yeah, PY... the Twitter of the Pontiac world.

The BW475 is a very good turbo, very spicy in the top end and also very heavy on the corner it's mounted. But, you know, it's much easier to just buy your turbo because it's the first one that pops up on Google Ads. No need to crawl through the maps of many turbos, factoring in converter, gears, tire/wheel sizes, car weight, fuel quality, target boost pressure, piston ring gap and engine management but most importantly, one should never comment on the PY boost section in fear of upsetting the retired boost engineer. But when the advertisement said I would make 635whp at 10psi on the hub dyno with me tuning it in a car designed purely for the street that also just finished a 600 non-eventful-and-reliable mile trip because the wifes Subaru has head gasket issues, god dammit, I just had to have it.

Have fun guys! I'm out.

[Tom Vaught]

Originally Posted by krisr

Yeah, PY... the Twitter of the Pontiac world.

The BW475 is a very good turbo, very spicy in the top end and also very heavy on the corner it's mounted. But, you know, it's much easier to just buy your turbo because it's the first one that pops up on Google Ads. No need to crawl through the maps of many turbos, factoring in converter, gears, tire/wheel sizes, car weight, fuel quality, target boost pressure, piston ring gap and engine management but most importantly, one should never comment on the PY boost section in fear of upsetting the retired boost engineer. But when the advertisement said I would make 635whp at 10psi on the hub dyno with me tuning it in a car designed purely for the street that also just finished a 600 non-eventful-and-reliable mile trip because the wifes Subaru has head gasket issues, god dammit, I just had to have it.

Have fun guys! I'm out.

I have not seen any Engines mounted on hub dynos going down the actual race track. Hub dynos do not include AERO or tire losses.

Facts vs partial knowledge of actual racing influences. Bragging, nothing more.

Tom V.

Same BS happened with Carb Flow Advertising. Instead to using a standard 20.4" H2O test flow point, you go to 28" of test pressure as it reports a bigger carb flow number. ADVERTISING.

[krisr]

Originally Posted by Tom Vaught

I have not seen any Engines mounted on hub dynos going down the actual race track. Hub dynos do not include AERO or tire losses.

Facts vs partial knowledge of actual racing influences. Bragging, nothing more.

Tom V.

Same BS happened with Carb Flow Advertising. Instead to using a standard 20.4" H2O test flow point, you go to 28" of test pressure as it reports a bigger carb flow number. ADVERTISING.

Tom, just be quiet mate. You're making yourself look like an old fool now.

Cheers!

[Marv]

The combo Charlie66 posted looks pretty good. Personally I'd stay away from the super-cheap eBay or Holset turbos. A BW will work, but there are (in my non-engineer-opinion) better options out there today from places like Pulsar and VS Racing, as KrisR said.

You haven't mentioned what your compression ratio is, if you're going carburetor or EFI (and what management), or if the bottom-end is forged, or if you've upgraded the oil pan/oil system at all. All of this stuff would affect what exact turbo I'd suggest because it will change how closely you have to manage your boost/cylinder pressures.

Personally, I'd do as Charlie66 suggests and go for x2 44mm gates for better control compared to operating one 60mm+ sized wastegate. An internally-gated turbo will also be nice and responsive, though I don't know of many in the size of frame you'll be after to suit a 400ci engine.

Originally Posted by Tom Vaught

I have not seen any Engines mounted on hub dynos going down the actual race track. Hub dynos do not include AERO or tire losses.

Facts vs partial knowledge of actual racing influences. Bragging, nothing more.

Tom V.

Same BS happened with Carb Flow Advertising. Instead to using a standard 20.4" H2O test flow point, you go to 28" of test pressure as it reports a bigger carb flow number. ADVERTISING.

So what's your recommendation for the guy who started the thread? So far you've offered nothing pertinent to his question.