dans94z28

iTrader: (2)

so given a street car setup pump gas and meth both cars at 10 lbs of boost s475 how much of a hp loss would it be going down to a 4.8 from a 6.0 roughly. thoughts and opinions

willizm

iTrader: (10)

I'm interested as well. With all other considerations equal i'd think it could be around 15-20% but would like to hear from some shops that turbo different CI motors. It may be difficult to get a good approximation with so many variables in heads, cam, cr, fueling, etc.

JoeNova

20% going by displacement difference. But then there are factors factors factors blah blah blah.

10 psi isn't going to require meth. Most people don't even kick the meth on (with a single stage) until 8-10 psi.

Clean94Z

iTrader: (5)

are you asking about peak numbers?

people now adays are so hung on dyno numbers and most only care about peak numbers not the area under the curve.

4.8's are rated at 260-295hp depending on year 270-305tq
6.0's are rated at 300-360hp depending on year and 340-380tq



add what you want to these numbers 10psi at 25hp per psi or 50hp cam and you can get a rough guess of the peak difference.. its all bench racing really.. but if you curious about the area under the curve.. check out this article of a 4.8 vs 5.3

http://www.superchevy.com/technical/...e_ls_slugfest/

While the 4.8 makes only about 11hp/36tq less at peak look at the graph were they laid them over each other.. all the way up the curve the 5.3 made more.. at 3700rpm it made 47tq more.

The better question for you is.... what are your goals? what car is it going in? the 4.8 will do work but will require more boost. 4.8 will want to rev! From what I have seen when researching turbo stuff for my truck it usually takes a 4.8 2-3 more psi to run with a 5.3...

you can pick up a gen 4 4.8 shortblock for $300-450 and a gen 4 6.0 for $700-1000.00...

Another thing to consider.. billet wheel turbo.. might help with some mid range. same thing goes... its not all about those peak numbers!! area under the curve is what gets it done!

http://www.theturboforums.com/thread...-turbo-results

just my .02

dans94z28

iTrader: (2)

Lets use me as the example since i brought the question up. 06 lq9 with 317s 10 lbs of boost went 10.29 @ 134 with a cheap ebay turbo. Now switching to a 4.8 with same 317s same cam etc what would it take to run the same numbers etc. Im not concerned with peak numbers but more of comparison loosing 1.2 liters. One difference would be the 4.8 would be using a s475 compared to a 6.0 w cheap ebay turbo choking at 5500 and falling flat

Clean94Z

iTrader: (5)

Not trying to be diffcult but thats kinda comparing apples to oranges... Same setup including same turbo I would say you would probably need 3-4psi more on the 4.8 to do the same thing depending on the weight of the car.

But changing to another turbo and having a choking issue at 5500rpm with the old turbo... thats a whole different animal in itself. now its 10psi on a 6.0 choking at 5500rpm vs 4.8 with a s475 that could rev to 7k or higher..

guess the only comparsion here would be the track.

dans94z28

iTrader: (2)

[QUOTE=Clean94Z;18148985]Not trying to be diffcult but thats kinda comparing apples to oranges... Same setup including same turbo I would say you would probably need 3-4psi more on the 4.8 to do the same thing depending on the weight of the car.

But changing to another turbo and having a choking issue at 5500rpm with the old turbo... thats a whole different animal in itself. now its 10psi on a 6.0 choking at 5500rpm vs 4.8 with a s475 that could rev to 7k or higher..

guess the only comparsion here would be the track.[/QUOTE

Lets take the extra variable out, the s475. Apples to apples as best as possible. Car is a factory weight 4th gen camaro.

Clean94Z

iTrader: (5)

I would say it will take 3-4 more psi on the 4.8 to do the same the 6.0 did.

dans94z28

iTrader: (2)

That to me doesnt seem that bad or that cid isnt so important with fi as with na

Sales@Tick

iTrader: (3)

Here is a rough estimate:

4.8:
Estimates 603hp/512tq

6.0:
Estimates 735hp/640tq

This is based off Borg Warner's Match Bot program.

dans94z28

iTrader: (2)

Is this based on the same boost martin?

Sales@Tick

iTrader: (3)

Yes it is.

Airflow demand is much different though as you can see.

stock48

iTrader: (17)

My guess would be around 100-150 hp at 10 psi with a S475. Now at 20 psi the 4.8 will be only 25-40 behind and at 22-24 psi the 4.8L will pass the 6.0L that chokes around 17-18 psi.

dans94z28

iTrader: (2)

Read a thread where someone did a s475 on a 4.8 and said it was really laggy. Dont know what size pipe he used but wonder how it would spool w 2-1/8" or even 2" crossover pipe. Said didnt reach full boost until 4800 rpm.

BottleFedZ346

iTrader: (17)

Sounds like something was wrong then.....

JoeNova

Sounds like he bought the cheapest S475, which has a 96mm turbine and a 1.32 A/R T6. Thats a big turbine for a 4.8.

Spectre86

iTrader: (42)

thanks for the link. good read.

Clean94Z

iTrader: (5)

billet wheel for the s475 is $225.00

can do that later! its a drop in piece!

BottleFedZ346

iTrader: (17)

Without knowing what heads were on the 4.8, who knows! Ton's of variables!

dans94z28

iTrader: (2)

For a 4.8 with a 96mm 1.32 ar t6 cam would be 230/230 .600/.600 113.5+3 lsa heads could be either 317s or 862. I am sure 862s would spool faster w the higher compression.