4.8/243's/s475: How Fast?
 

Putting together a little turbo combo this year and was wondering if anybody is running 243's on a 4.8 with a S475? And if so, how fast? What power did the combo make?

I have stock 862's as well, but picked up the 243's for $100 bucks! Figured they would be a better flowing head vs the stock heads?

Should put you around 9:1. Gonna need a decent cam to spool a s475 assuming you are going 1.10ar t6

Jay

I plan on running LJMS "stage 2" turbo cam....

It's a T6 1.32 at housing .96mm wheel, hoping for 750-800whp.....

Should make that easy if you ain't afraid to turn it up. With the a/r that big it may be laggy but in my book who cares really. Unless a race only car its still gonna feel nasty. Even if it takes till 4500 to be online lol.

What's the specs on the LJMS Cam? Is this a stock 4.8? That would be a nasty 4.8 if 700 800hp if it hits that. I'm at the point of between a 4.8 or 5.3 so this would help me also if more people would chime in.

Yes, stock bottom 4.8!

Car is getting a brake on it so it really shouldn't be an issue I don't think! Im also not scared to turn it up, I plan on pushing this little motor pretty far......

I had a 4.8 with 243's and a ls9 cam with a s472 1.10t6 and it spooled good. id say with the bigger cam it will be fine. I had the 75mm at 22psi but don't know the power tho...

Well the s475 will push the power for what it is. Im making 23psi on my stock ls1 with one. Power unknown at that level though. Here is a video of a 4th gear roll with it set on 21psi. Give you an idea on spool. I know your will be a little slower but I have the 1.32ar 96mm turbine like your gonna run. And a 3.42 gear in the rear and 28" slicks. Also have a cam speced by Martin@Tick.

That was floored at 2500rpm's? lol, geez i guess im used to my big stalled auto flashing and spooling faster.

light enough car should go 8s at 150+

my friend has done it

/edit with less turbo than a s475

What was the setup?

Waited more till like 3000 to actually hammer it. But yes auto spools way faster. 12degrees timing and pump gas. Sure the op car will spool a little slower but I'm not one to be to nit picky about spool time. Not sure how anyone else feels. Most people that build cars on here are not strictly race cars and taking a second or so extra time to spool on the street is not that big of a deal to most. Its all in what your happy with. If I'm racing I'm not gonna hit it unless its right there at ideal spooling rpm. Once turbo is online it stays there. The video was just to show what boost pressure it wasn't a test spool up time.

I'm shooting for 8.80's @ 148-150ish mph, should make a fun street car!

I'm building a 5.3 with a s475 and a freak show performance power glide and 9inch btr stage 3 cam and holley high rise is a stripped out 86 trans am. With 27x10x15 slicks.. hoping to break the 8s barrier also.. The s475 is a huge turbo.. first one I've ever bought.. go to my build thread and u will see it

I'll check it out!

Forgot to mention my car weighed 2620lbs last time @ the scale, so I don't think my goals are to far from reaching......

At 2600 pounds it will be moving out for sure.

gen3 4.8 with gen4 pistons and rods.
74mm garrett clone turbo, 4 inch air to air, stock pcm, twin walbro 255s in the tank, 200r4 trans.

22lbs of boost 711rwhp ish

Have any idea what his car weighs?

PM Dezlfreak on here. He has a 4.8, my custom 215/225 111lsa cam, 243's and a S475 on 15psi went 9.55@147 mph with a 1.6 60' on his first pass with his combo.

3400 lbs race weight.

Has a ton left in it. That turbo should make every bit of 30psi on a 4.8 with stock 243 heads.

I was thinking somewhere in the 22-23lb range to get me where I want to be!