ive read a few similar threads on this topic,
im still yet to get a dyno tune.
im running
5.3sbe ljms2 cam, bws480 80/87 1.25
glide 1.8
3.54 rear 28"tyre

car is a street car primarily, originally i wasnt too concerned with spool time, but i have decided that without running big boost and aiming for 1000+hp might be kinda pointless.
instead of going a smaller turbo and fabricating everything up again to suit.
would i get much better response , with a stroker bottom end setup on the 5.3 bringing it to 360ish ci ?
or would i need 400+ci to get it bit more responsive


this is from 10mph then full throttle

 

My car had a Lsx 376 9 to 1 comp, tick stage 2 cam, 3500 stall ptc converter in a 4l80e, s480 96mm on a t4. From a dead stop without loading it if I stomped it wide open id be full boost with in a second. I think you'll be fine if you stoke it to 360 cubes.

 

What's the goals for the car?

 

Only a street car, but just hitting the throttle from a stop or a roll , it won't spin the wheels. I'd like it to feel a bit quicker.
might try switching to some 26"tires aswell
it needs a tune,

and I'm gonna go through all the hot aide make sure there are no leaks.

but I think between the glide and 3.54 rear and bigger turbo, that might be just how it is

 

Power goals and shift points are also good to know. If you don't want more than 600hp or something then you don't need an S480.

 

Something around 800engine HP. Shifting 6500

 

So 700whp or so. If that's really the max that you want I wouldn't run an S480.

 

Biggest thing with the large frame turbos IMO is a properly sized divided hotside and timing...... you have to keep N/a timing till like 4-5 lb of boost and keeping the hotside divided the whole way to the turbo flange make a huge difference in the twin scroll turbos... wait till it’s tuned and go from there

 

My S480 was near-instant on my 5.3. The cam/converter/turbo combo were so perfect that basically whenever my foot was down, I was in boost, even lugging it in high gear.
Traction was almost non-existent until I started experimenting with tires, timing curves and shift points.

My corvette is massively over-turboed for the 4.8 I'm running now, but its really the only reason I get any kind of traction. Trade-offs...
The S480 can work very well on a 5.3 with the right combo.

Sadly, two identical engine/turbo combos won't spool the same if they aren't using the same tune, fuel, timing tables, torque converter, etc.
Lots of things play a big role.

 

Awesome auto what trans and stall did you run with the 5.3??

i have s s300 69/73 gen2 with .91AR

im thinking this might suit what im afyer better , but i just want to make sure before i spend bit of cash to fit it up

 

I was using a JFR 218/218 112 LSA cam on an L33 with 93 octane, 4L80e with a 3200-3400 258mm billet triple disk from Circle D.
It would make 26 PSI before 4000 RPM with an S475/87 with a 1.10 A/R T4. I was in double digit boost by 3200 on the street.
I BARELY noticed any difference in spool swapping the compressor wheel out to a billet 80mm and keeping the same turbine.
The car was basically a rocket all of the time. I ended up destroying a 4L80e which eventually led to a 3-year long rebuild process /w upgrades to the chassis.

It now has a very well built 4L80e in it, and for the time being it has a stock LQ4 with the same cam/converter/turbo combo and boost hits almost too fast.
Even though its on very low boost and pump gas with the stock LQ4 (like 9 PSI or so), it runs easy 9s.


My 4.8 has quad 50mm turbos on it, which mathematically put it very very close to having a pair of cast VS 7875 turbos.
Its lazy on the street. Boost doesn't come in until 3200 and builds slowly until 4800 RPM.
The back of the car is light enough that 2 people can pick it up off of the ground, and its on junk $160 325 wide street tires that hook like its raining.
It also runs 9s on 9 PSI, despite feeling like a lazy turd most of the time. Spool time won't have a huge impact on track times since you're almost always in the upper RPM range.

If you want something that spools fast on the street, I'd recommend not going for something that spools too fast.
It gets pretty annoying when you slide around everywhere at part throttle and you can't hook well enough to enjoy the pull.

 

What fuel are you running? 10.7 AFR is awful rich

What does the timing curve look like? Fuel curve?

I'm betting the issue is in the tune, not the engine size.

 

^This... 10.7 is pretty fat, you sometimes need to run SBE a little fat but not at 14lbs... more like when at 30+. 14* on 14psi is also a bit soft for a low compression SBE5.3. I bet you get the tune dialed in it will wake up a lot.

 

I'm running a billet S484 T6 divided flange on my 5.7 LS1 through a TH400, 3.55 gear and 28" tire and it comes on like right now lol.
It actually seems to come on faster than my old LS1 T56, 3.73 gear with a older T7875 T4 open flange setup.
If I can make 800whp on pump gas I'll be very happy, 1000+whp on race gas very happy.

 

running e85 , have had car on a dyno set up a base tune but didnt get right into adding a lot of timing.
i have tried running 28* to 5psi and 12:1 fuel , takes off a bit quicker , but i doubt u can tune the spool up much more than that ??

 

Still a bit fat for 5lbs on E85. I keep it at 12.7-12.8 for first few lbs, drop to 12.5 for next few, etc. I dont get to 12.0 till about 10lbs, then as it reaches target boost and load hit 11.5. Some guys push near 12.0 with higher boost on E85 with good results, just have to see what your engine wants. If you really start crankin the boost up then runnin a bit richer at peak boost wont hurt, sometimes more fuel to cool cylinder is beneficial at that point.

Same with timing assuming your 100kpa timing is correct keep it all in for first few lbs, then remove half a degree per lb after 5-7lbs. Again until boost gets fairly high then you may need to pull a degree per lb or more depending how the plugs look.

That’ll generally get you in a fairly sweet spot and not be laggy.

 

Theballss is that from just mashing the throttle it comes on quick .
Would the glide be making it too slow down low and therefore spooling slower

 

Would there's still be a lot if benefit to running the 69/73 turbo. I'm assuming would spool up surely much quicker.

I've got a tune booked in soon, said like to make the right decision

 

I just bought the car so I was goofing around on the street getting acclimated to the car, I didn't even mat the gas all the way.
Pulled away from a stop light so was going maybe 5-10 mph and rolled in really quick and the gauge hit 11lbs. really fast.
I had a six speed car with a 7875 that wouldn't spool as quickly so I was very surprised to see how quickly the larger S484 came online.
Definitely start with the tune, might need more timing down low to get the turbo spooling, is it a twin scroll exhaust housing?

 

Open scroll, would be hard to make a divided setup now.
Tune could help for sure, but it's expensive here for a good one. So I want to have the right setup when I go