The bigger turbo/billet wheel/race cover will move the compressor efficiency up and to the right. That is a good thing when you're running big boost levels and turning a bunch of RPM.

However since you're running at such low boost I would actually expect to see the IAT get slightly worse at 9psi. Why would that pick up 50hp?

What trendz is trying to say is that different turbo's, CID, boost level, heads, etc... Will all want a different cam grind. Some combination of the above will be more like a Na cam, and some will want something more obscure.

Some turbo cams are ground with a reverse split duration, some are not.

Too many factors go into it to generalize anything.

Just talked to Mike at Bullet, Man do I have a headache now, way to much info to take in. Cam he spec for the engine now is nothing like what it needs with 120 more cubes and another turbo, new that was coming, for this engine think I'm just gonna find a shelf cam with enough lobe sep and lift I can live with until I go bigger. Hot rodding ain't like it used to be, but then again thats why we have street cars that bust 170mph In the 1/4 now.

Well gonna run the Comp I have unless someone buys it from me,
It will run what it runs, this is my first v8 turbo, It will run good I'm shur, and when I get another block and rotating assy I can lean on I will buy a "proper" cam.

Thats just a N/A cam.. if I were you I would do
some calling to get a proper cam.. something in
the 114 LSA... you can sell that cam latter

If someone buys it I will order a custom grind, it's new never ran,
It's a month away from being together.

Before you get started on this project and disapoint yourself...

The link below is a borg warner 75mm compressor map at only 10psi of boost on a 500" motor (assuming a 4.25" crank and 4.34 bore). As you can see you are off the entire page (let alone the chart!) by 5000 RPM.

A cam that is 283@.050" is going to want to spin fairly high RPM, which will be a terrible match with this turbo.

To make a 75mm work on a motor this small, you'll only be able to turn it to around 5000 RPM, which would literally mean stock cam.

If you want to turn it to a lot of RPM, then you need a much bigger turbo.

Just don't want to see you spend a lot of time and effort putting a bunch of mismatched parts together...

http://www.turbos.bwauto.com//aftermarke...rsin=92044&

I like that comparison chart you put up
Doug.. I had to save it

I'm assuming the cam profile would change the volumetric efficiency characteristics at different rpm. But aside from guessing about that - I don't understand how the app comes up with info about wastegate sizing. I played with turbine expansion ratios - but it still says I'm wastegate choking?

100% volumetric efficiency is never going to happen with a motor designed in the 50's.

I have Indy heads and a turbo cam and my V/E numbers are in the 80's at 30 psi acording to my FAST fuel tables.

What would be a reasonable "guess" about VE numbers be? 70's?

Look at some dyno sheet... A 440-1 indy head on a 500“ motor will make 100% no problem. My home ported iron heads went around 95% VE.

Especially at low boost

I didn't do anything on the turbine calculations because I was just pointing out the compressor mismatch. You can use this tool for wastegate and turbine calcs tootoo.

A 75mm on a 500“ motor not work well.

It's just a .030 400 right now, I will by another of the same size turbo after I get it all together save for the hot side.

Ah I was confused because you mentioned the 4.25 crank. It will work just fine on a 400".

That cam is still way to big, but at least you're not mismatched on the turbo so bad.

Probably only needs a cam in the 240/250 range. 280+ is going to want to run higher than the turbo can support on a 400" motor.

Yeah Bullet spect one I think at 254, might throw a big Hyd flat tappet In it for now,

this is my cam from scott brown hyd roller ground for 1.6 rockers
adv dur int 293 exh 303 at .050int 239 exh 248 valve lift int .548 exh .610
lobe sep int 110 exh 118 lobe sep 114 spring press 175 reat 425 open
this is a 8.32 comp 440 motor all aftermarket block heads rods crank everything to stock size 440 but made to take the beating of big boost i hope. i was very happy it dynode 510 hp with a 750 carb last weekend when i picked motor up.

What turbo/turbos are you going with?

well we have talked to precision-works turbo and a few more to get a size and basically they all wanted cubic inch and compression and your goal for hp with my combo of 440 and 8.3 comp 88 ml is perfect anything smaller your wasting your time and money but at 88 mm 1000 hp at crank is about max depends on wich turbo you buy. i have a line on a nice precision 94 mm so i can make more wich is funny my whole goal is 9 sec car pump gas but this thing has gone out of control on the budget side way the hell over. my advice call scott brown at buyracingparts.com he will mahe you a great cam my setup was about 900.00 cam lifters and springs

That 88mm will make way more than a 1000 at the crank,
There is one on youtube basically same build, stock stroke 440 eddy heads but with stock block made over 1200 at 16psi on pump gas.

"my whole goal is 9 sec car pump gas.."

I hate to say this, but if that was your goal and you are "out of control on the budget side way the hell over" then you either underestimated big time or didn't plan it out to thoroughly. You should accidentally run in the 9's with a 440 and 88mm.

this dart was going to be a 440 with nos on stock block - no paint well a buddy with a 5.0 stang bought a 120,000 mile 5.0 for 500.00 a turbo kit for 1200.00 put this junk together and went 10.20 so my plan changed and let me say 5 years ago i could not find anyone running 440 with one turbo so this car has been changing. 2 years ago i decided to go and build the most durable street turbo motor that was 440 cubic inches world 4.25 bore block 4340 8 bolt mp crank manley pro I beam rods icon off the shelf pistons ( engine builders choice ) hyd roller cam by scott brown - T&D 1.6 rockers had a s480 turbo i was told it will run out of steam quick so now after getting better info and seeing the you tube motor dyno i think we are getting close. as far as time slips i believe when i see it. alot of people like yourself say im under estimating what the car will run and im fine with that. until i get this pig done i want to have my mind blown i know my wallet is.
buhahahahahahahahahaha still learning about turbos