Am I crazy for wanting to downsize?

[chevyburnout1]

Just go stock over s480 Dustin. Truck ran awesome up there this weekend and spooled really fast even at 10,000ft.

Colorado mountain range passes for you. even more fun when you have 12k on the back too

If I would do it all over again I probably would go that route haha. As funny as this sounds it's more cost effective to bolt on a Garret charger instead of converting back to stock/s480 :roflmao: The poor girl has been over those passes multiple times throughout all stages of it's life. Hauling a camper with the old 72/94 combo over Eisenhower wasn't exactly a walk in the park, but it was still fun nonetheless haha.

The gtx3582r would make a screaming little high pressure charger for getting things going at your elevation. Do you have an overall horsepower range you still want to maintain? That with a gtx5018r would make a killer combo....

This right here! This is what I have been contemplating. A moderately small high pressure charger to take care of drivability and most importantly smoke, paired with a drastically larger atmosphere to take care of the horsepower needs. I was 55hp away from touching four digits power and wouldn't mind finally hitting that mark at least once with this setup, but dyno numbers really aren't priority for me. Would like to run consistent mid-to-high elevens at this elevation, still have decent street manors, but most importantly with almost zero smoke. Smoke is definitely the driving factor here. If it wasn't for that truthfully my setup now would be satisfactory.

The GT3582r/GTX5018r combo is definitely intriguing and roughly where I am going with this. The flow and pressure ratios that I've calculated out put all three chargers (3582, 3788, 5018) on a very decent part of their flow maps. Especially if I cinch down the turbine housings and drive them hard. The main question that I have little knowledge of is when and how does the small charger really start hindering the larger charger? Some late night studying has led me to thinking the GTX series would be a better atmosphere with eleven blades, where-as the normal 6/7 blade GT series would be more suited for the high pressure setup. Less blades for a little less flow-through restriction. Only real theory I have at the moment, but in regards to actually hurting performance I have little knowledge of.

I appreciate every ones input on this! I've never really been the one to run with the "crowd" per say as I like being a little different. The math and theory behind what my truck can do versus what actually happens is really what intrigues me about this sport. All of you guys have been drastic help over the years and has accomplished what my truck is today :hug::beer

 

[delong_1]

honestly the gtx are low pressure stuff, typically we run the atmo at a high pressure ratio as well.

 

[Verlon at ATP]

If you aren't going for 1k plus on horsepower but want great egts and excellent spoolup, I don't think you will be hindered by the 11 blade on the high pressure charger.

Rob ran a gtx4204 for 5 years on max'd out as the high pressure and had excellent results. I ran a gtx4294/gtx5518 setup last year. It was a good setup for most things, but towing was not one of them. High pressure to big to run rpm I wanted while towing.

I am definitely not good with turbo theory, but I have tried many combos, driven many others, and am still trying to find the perfect setup. If you have the hookup at work on the garretts, just give it a try. If not what you want, sell turbo for more than you paid.

 

[mike diesel]

Verlon,

I swapped in a billet 11 blade into my high pressure s472...it does ok I guess, would you recommend I go back to the cast 7 blade wheel? I'll have the turbo out here shortly.

 

[chevyburnout1]

I'm back! Been absent for a while. Bought a boat and it basically took up the rest of my free time and then some! Pretty sure that is the definition of a boat! So anyhow as of literally today I swapped to the GT3788 with a .89 a/r. This truck is a completely different animal! Haven't gotten on it much yet as I'm still waiting for the coolant lines to be built but wow is the difference drastic! No more horrendous lag and blue smoke/burning oil smell. I can actually make boost below 2300rpms and fuel smoke has been cut down to "hypertech" fueling characteristics. Going to get the coolant lines finished and get some miles on it this week. Will get some good number and ET readings by this weekend for our local "Truck Fest" races at the strip.

 

[Stancedlb7]

Saweet! We all enjoy vids!

 

[malibu795]

I'm back! Been absent for a while. Bought a boat and it basically took up the rest of my free time and then some! Pretty sure that is the definition of a boat! So anyhow as of literally today I swapped to the GT3788 with a .89 a/r. This truck is a completely different animal! Haven't gotten on it much yet as I'm still waiting for the coolant lines to be built but wow is the difference drastic! No more horrendous lag and blue smoke/burning oil smell. I can actually make boost below 2300rpms and fuel smoke has been cut down to "hypertech" fueling characteristics. Going to get the coolant lines finished and get some miles on it this week. Will get some good number and ET readings by this weekend for our local "Truck Fest" races at the strip.

I can pull 18-20# under 2000rpm with my hybrid setup only with a load tho to hold the truck back....

 

[chevyburnout1]

I can pull 18-20# under 2000rpm with my hybrid setup only with a load tho to hold the truck back....

Right now I'm just running my daily driving tune which has less pulse than a stock tune. I stabbed it a bit going to work today and it easily hits 30psi, coming alive hardcore around 1700rpms, with the atmo charger barely budging. My new infatuation is the turbo speed sensor gauge however. Such a slick setup, but I need to make sure I have it setup correctly for the number of compressor fins. That 30psi pull easily put it over 100k in rpms, and looking at the speed lines on Garrett's flow map that's already pushing it. Going to have a lot of wastegate tuning with this setup. I'm a little worried now my single gate wont be enough! Oh well it's just speculation at this time. I'll get some good videos when I start dialing in the tuning :woott:

 

[malibu795]

Mine for what ever reason falls on its face bellow 1800.. The heavier I am the more noticeable it is. Did it with both turbos.. Course I got longer than stock legs 32" vs 30" tires..
You got a T4 housing right?
Definitely wonder if I'm choking the turbine with T3 housing..

 

[Chevy1925]

And here in building 10-15psi of boost at 1500rpm

 

[malibu795]

And here in building 10-15psi of boost at 1500rpm

I can pull 15# @1500rpm buya really smokey and makes alot of heat... And I don't accelerate

 

[Chevy1925]

I can pull 15# @1500rpm buya really smokey and makes alot of heat... And I don't accelerate

Yeah this is clean boost and accelerating. I can push more but it's borderlined downshifting to 4th

 

[malibu795]

Yeah this is clean boost and accelerating. I can push more but it's borderlined downshifting to 4th

Yes smaller turbo will do that

 

[Chevy1925]

Yes smaller turbo will do that

No way! Lmao

 

[chevyburnout1]

Mine for what ever reason falls on its face bellow 1800.. The heavier I am the more noticeable it is. Did it with both turbos.. Course I got longer than stock legs 32" vs 30" tires..
You got a T4 housing right?
Definitely wonder if I'm choking the turbine with T3 housing..

T4 .89ar housing. I don't have the best info to give you yet as the tuning is still in the works. All I know is it feels almost like stock and I'm plenty happy compared to that junk Comp Turbo 67.

Got to run it at the track Sunday and I think I found one of the characteristics of a excessively small/large compound setup. It was just like what delong had mentioned to me, the power is not as "linear" when running the larger tunes. It feels like it actually made the large charger a bit more laggy so launching it was a bit hard. The first run I launched around 20psi and didn't get the large charger to light until about half track. Seemed a combination of instant full fuel combined with some moderate defuel on the shifts is what effected it. So the second go round I tried a second gear start and launched around 30psi. Lit the large charger way sooner and cleared the smoke right up. But unfortunately my passenger uppipe decided to blow about half track. Managed an 11.99@119mph. Will get these pipes upgraded and get some decent tuning and practice runs in. But overall I'm super excited with how its running out!

 

[chevyburnout1]

Here's a video of the run. Please excuse my friends quality video skills haha. You can see when the smoke clears and the atmo charger lights. I feel once I swap the Comp 88mm/1.21ar to an 87mm Garrett and a 1.0ar it should light much quicker and be a damn good setup. And most importantly, a clean, cool, smoke-free setup.

[YOUTUBE]YDiTANrmCGE[/YOUTUBE]

 

[Burn Down]

Nice run! Sucks you had so much trouble with Comp... Makes me nervous about mine

 

[chevyburnout1]

Nice run! Sucks you had so much trouble with Comp... Makes me nervous about mine

Thanks! Still needs a lot more tuning but I kept the same mph as my old setup with nitrous so it's going the right direction! My big Comp still seems to be working OK. Spits a bit of oil and blue smoke under higher boost, even with two oil restrictor in it, but keeps at it haha. I personally think Comp's small chargers just can't handle the heat from our diesels. The CT43 aluminum bearing cartridge is so tiny and lacks water cooling that I think it just cooks the bearings. Every time I would get them rebuilt it would run fantastic for a few weeks, then just start getting more and more laggy and start spewing oil and blue smoke.