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Hey guys, I’ve never done a supercharger before I wanted to get your input.
The car is an 87 Monte SS with a 2000 6.0/4L80E swap I did about 7 years ago. 4L80 is stock rebuild with a Yank 3200 stall (tight) and aux cooler with fan. LQ4 I built myself and is bored 4.030, weisco -2cc flat top pistons, Callie’s rods, stock crank, GM MLS head gaskets, 799 heads untouched, LS2 intake, 78mm TB with 4 bolt/90mm adapter and 230/236 .614/.610 113 cam. 10.98 CR, rings gapped for N/A and made 350rwhp/350rwtq. Stock rear right now but in the works of doing a 9” more than likely with 3.73 gears. Truck accessories as well, Grand National fuel tank with 255 pump.
Car will be a street machine with many trips to the strip planned. Want it to run 6psi on 93 but intend to do a flex fuel sensor later and up the boost.
I originally intended to go turbo but i have really been looking at a TVS 2300 with plans to do an ice box with the heat exchanger. Any other S/C’s You recommend?
What are are your opinions? I know CR is up there. Should I get some heads with a larger chamber to knock that down? Thoughts on meth? Cam swap obviously (btr stage 3?)
I have an 83 cutlass ly6 with a whipple 2.9 . I love it . Fits under the stock hood with the Holley pan/ mounts. The harrop 2650 is supposed to be the hot new ticket but I’m not sure about intake temps witch could be an issue with your high CR.
I'll be completely honest... a well ported (Modern Airflow Dynamics, Kong, Jokerz) 1.9 LSA blower is pretty hard to beat. Even the guys that swapped from an LSA to a HeartBeat didn't gain much at all with it.
If you don't want to run adapter plates for the heads the GM ported LS3's are best bang for the buck.
I've been wondering for a while now, what boost are you guys seeing off idle? I realize its never going to be like a roots type as far as low rpm boost but still curious when it starts to pick up.
If anyone had any graphs with boost by rpm, that would be great. Ive driven 4cyl cars with massive turbos and thus lag, I'm trying to get a comparison. My built 2.0 4 banger would full spool a huge turbo at 3600 rpms.
I also understand there is some variance in this test like CI, intake/head/exhaust flow characteristics, what brand/model of centrifugal charger it is.
I've been wondering for a while now, what boost are you guys seeing off idle? I realize its never going to be like a roots type as far as low rpm boost but still curious when it starts to pick up.
If anyone had any graphs with boost by rpm, that would be great. Ive driven 4cyl cars with massive turbos and thus lag, I'm trying to get a comparison. My built 2.0 4 banger would full spool a huge turbo at 3600 rpms.
I also understand there is some variance in this test like CI, intake/head/exhaust flow characteristics, what brand/model of centrifugal charger it is.
The bottom line is my boost, it's a WOT pull. Personally I like the smooth delivery since the car is on street tires 99.99% of the time, but my preference isn't everyone's
EDIT: This is also with the ATI balancer + fbody 8 rib belt and 4.5" blower pulley
Last edited by blackandgold; 05-21-2019 at 04:55 PM.
And unless it's a very heavy vehicle or you are towing etc...do you really need boost off idle ?
Someone did post a few graphs a while back of a TT car, a centri and Roots, although not from idle of course. But even the centri...whilst it may not make positive pressure on a gauge, even from around 2500rpm, was still making damn good power/torque compared to the Roots car
I've said it for a long time...be under no illusion that centri's do nothing for performance at lower revs because they make no boost there. They absolutely do.
I've run the same engine on my car with a YSi, n/a and twin turbo, and even driving say below 2000rpm ( which even that is still easy to achieve illegal speeds very quickly ), the difference between the YSi and n/a is huge. The TT is fairly lethargic compared to them both, although obviously as rpm's rise things do change.
I've run the same engine on my car with a YSi, n/a and twin turbo, and even driving say below 2000rpm ( which even that is still easy to achieve illegal speeds very quickly ), the difference between the YSi and n/a is huge. The TT is fairly lethargic compared to them both, although obviously as rpm's rise things do change.
So the Twin turbo slows the car down quite a bit out of boost vs when the same car was NA ?
Stevie is absolutely correct re: low rpm power with a centri. Plenty of it with no concern.
My experience coming from a small magnusun MP112 ( roots style blower) & entring the centri world was that I had concerns of low end grunt. I bought into the hype re: centri are for top end & better for the track yada yada. To mitigate that I went down a rabbit hole. I started out with what I call the “waste gate experiment”. We reduced the pulley made a ton of boost ( especially down low) & blew it off with a wasregate at about 14 lbs to avoid over boosting & excessive wear & tear. the idea was for me not to lose my precious TQ in lower rpm range. I’ll spare you the diatribe & details. ( there is an entire thread from a few years ago about this subject), bottom line: that was a tremendous overkill & plagued with inefficiencies.
I leaned the hard way that my ProCharger had more than enough to offer under the curve. Even at your 9lbs peak you will make plenty power at 2500 - 3000 rpm range. As you escalate to 4K - 6K .... this is where the centri shines strong. Hold on to you ***.
Correct, boost is a measure of restriction. It's still one of the indicators to determine what rpm something adds manifold pressure above atmospheric though. Most companies don't show CFM flow and if they do they don't show it by rpm x pulley speed.
So the Twin turbo slows the car down quite a bit out of boost vs when the same car was NA ?
In my case, I went from large long tubes when n/a...to factory cast manifolds with a big turbine wheel stuck in the middle of the exit path.
And then change a free flowing intake...ie TB to a large air filter....to a few 90 deg bends, a large radiator core ( the intercooler ) and then the compressor wheel /housing.
So yes, off boost on a lot of turbo cars the system has been made much less efficient vs a very good n/a setup.
Which is why any build is important to optimise it for what you're doing etc. OEM cars will have small turbos that spool very fast these days, with a small sacrifice up top.
Those who want more will make that sacrifice at the bottom, to make more power at the top end.
The sacrifice with the blower is the power to drive the blower, although you never get to feel that loss as a driver so mostly it's a win everywhere especially a centri.
But you could build say a TT with very small turbos that would be very responsive at very low rpm, and still offer a good power increase up top. Just depends on all round goals etc.
Last edited by stevieturbo; 05-23-2019 at 12:17 PM.
Stevie is absolutely correct re: low rpm power with a centri. Plenty of it with no concern.
My experience coming from a small magnusun MP112 ( roots style blower) & entring the centri world was that I had concerns of low end grunt. I bought into the hype re: centri are for top end & better for the track yada yada. To mitigate that I went down a rabbit hole. I started out with what I call the “waste gate experiment”. We reduced the pulley made a ton of boost ( especially down low) & blew it off with a wasregate at about 14 lbs to avoid over boosting & excessive wear & tear. the idea was for me not to lose my precious TQ in lower rpm range. I’ll spare you the diatribe & details. ( there is an entire thread from a few years ago about this subject), bottom line: that was a tremendous overkill & plagued with inefficiencies.
I leaned the hard way that my ProCharger had more than enough to offer under the curve. Even at your 9lbs peak you will make plenty power at 2500 - 3000 rpm range. As you escalate to 4K - 6K .... this is where the centri shines strong. Hold on to you ***.
The D1SC on my TBSS is wastegated and it works great. So I guess there is that.
On the street it doesn't take a ton of power to break the tires loose, I have a LSA supercharged LY6 that's stock except for the blower and LS9 cam backed by a TR6060. I'm running 325/30/19 Nittos and can pretty much break the tire loose at any legal speed limit. I'm actually running the wrong gear, with 3.42 ratio I can cruise at 70mph @1,500rpms It really needs 3.90 or 4.11, I'm sure a gear change is not going to help the traction issue lol The track is where you're choice of roots/centri/turbo is going to make the most difference. My truck is setup more autocross style so I choose the LSA supercharger because it works very well when using a manual trans and want power to be more linear for predictable power when getting on and off the throttle.
I make 8 to 10lbs of boost and have another pulley that would bring it to 12-14lbs but don't see the need for it right now.
On the street it doesn't take a ton of power to break the tires loose, I have a LSA supercharged LY6 that's stock except for the blower and LS9 cam backed by a TR6060. I'm running 325/30/19 Nittos and can pretty much break the tire loose at any legal speed limit. I'm actually running the wrong gear, with 3.42 ratio I can cruise at 70mph @1,500rpms It really needs 3.90 or 4.11, I'm sure a gear change is not going to help the traction issue lol The track is where you're choice of roots/centri/turbo is going to make the most difference. My truck is setup more autocross style so I choose the LSA supercharger because it works very well when using a manual trans and want power to be more linear for predictable power when getting on and off the throttle.
I make 8 to 10lbs of boost and have another pulley that would bring it to 12-14lbs but don't see the need for it right now.
If you're making any sensible power at all, the last thing you need is shorter gearing like 3.9 or 4.11
If you're making any sensible power at all, the last thing you need is shorter gearing like 3.9 or 4.11
Normally I'd agree but I'm running the close ratio 1LE version of the TR6060 and it has a 2.66 1st gear so it has little to with power while moving it has more to do with clutch release to get the truck moving and keeping it rolling at low rpm, I feel I wouldn't have to slip the clutch nearly as much with a lower ratio when taking off and it will make stop and go traffic a little easier.
It's not really going to hurt traction in 1st and 2nd gear it doesn't have any as it is lol
Last edited by LLLosingit; 05-25-2019 at 09:21 AM.
Normally I'd agree but I'm running the close ratio 1LE version of the TR6060 and it has a 2.66 1st gear so it has little to with power while moving it has more to do with clutch release to get the truck moving and keeping it rolling at low rpm, I feel I wouldn't have to slip the clutch nearly as much with a lower ratio when taking off and it will make stop and go traffic a little easier.
It's not really going to hurt traction in 1st and 2nd gear it doesn't have any as it is lol
Shorter gearing will absolutely make 1st and 2nd even less use.
And I've a 2.66 first gear and 3.27 rear ( tyre circa 26" ) and it's no issue driving. Certainly never have to excessively slip the clutch unless literally stuck in stop/go traffic. But that's rare for me anyway
If you do encounter that a lot then yes shorter gearing will help, as will a normal organic type clutch if you arent using one already
05-13-2019, 06:57 PM
LS Swap Supercharger suggestions 
