Dyno'ed again..455HP

[Genaris]

Got my SSR retuned by reece at MTI racing...Better results this time, but I still have a slight hesitation or pause when the engine is at complete idol. is this normal? Shouldn't the response be instant? Does everyone with a Maggie have this or is it just me?

my build...

LEP Custom Blower Cam – 224/230 .612/.612 116LSA
Dual coil valve springs
Hardened pushrods
LS7 Throttle Body
NGK TR6 Plugs
Supercharger
2.7” SuperCharger Pulley (9lbs boost)
Forged pistons w/File Fit Rings for Boost (stock bore/ flat top)
Forged Eagle Rods with Stock Stroke Crank
Comp timing chain
SSR Walbro Fuel Pump Upgrade (Lingenfelter)
Phoenix Transmission PTGM55HSX Torque Converter Custom Stalled (2600-2800)
Billet 2nd Gear Servo
Billet 4th Gear Servo
Kooks 1 7/8" Primary Headers with 3” Collectors
High Flow CAT’s
Corsa exhaust
4.10 gears
Addco sway bars
Amsoil air filter
Amsoil transmission fluid
Amsoil Gear oil
93 octane always used


I still think my numbers are low........

[Chick]

Originally Posted by Genaris

Got my SSR retuned by reece at MTI racing...Better results this time, but I still have a slight hesitation or pause when the engine is at complete idol. is this normal? Shouldn't the response be instant? Does everyone with a Maggie have this or is it just me?

my build...

LEP Custom Blower Cam – 224/230 .612/.612 116LSA
Dual coil valve springs
Hardened pushrods
LS7 Throttle Body
NGK TR6 Plugs
Supercharger
2.7” SuperCharger Pulley (9lbs boost)
Forged pistons w/File Fit Rings for Boost (stock bore/ flat top)
Forged Eagle Rods with Stock Stroke Crank
Comp timing chain
SSR Walbro Fuel Pump Upgrade (Lingenfelter)
Phoenix Transmission PTGM55HSX Torque Converter Custom Stalled (2600-2800)
Billet 2nd Gear Servo
Billet 4th Gear Servo
Kooks 1 7/8" Primary Headers with 3” Collectors
High Flow CAT’s
Corsa exhaust
4.10 gears
Addco sway bars
Amsoil air filter
Amsoil transmission fluid
Amsoil Gear oil
93 octane always used


I still think my numbers are low........

I'll let you know ! My stock numbers were 360hp, on 6 month old gas, with a Westers-Tune and Mikes True-Duals.

This round is for a new Westers-Tune and the MagnaCharger setup for 8lbs of boost.

Stats when complete:

- 2005 6LTR LT2
- 190 Degree Thermostat
- Westers Tune (89/93 Octane)
- Lingenfelter Fuel Pump Upgrade with MagnaVolt
- 2.7" Aluminum PullyGuys Pulley (6/8lbs Boost ?)
- MagnaCharger
- 90mm Lingenfelter Polished Corvette Throttle-Body
- K&N Air Filter
- Denso 0.4mm Iridium Plugs 1 Range Colder
- 6 Speed Transmission
- 4.10:1 American Rear End Gears
- Mikes Aluminum Extra Capacity Rear-End Housing
- Mike's True-Dual Exhaust System
- Mikes Engine Fan Replacement
- Air/Fuel Gage, A Pillar Mounted
- Boost Gage, A Pillar Mounted
- Polished 200 amp GM Alternator
- Improved Engine Air Flow Model At Firewall
- Addco Sway Bars Front & Rear
- Mobil1 Fluids All Around
- Katzkin Black & Silver Leather Seats & Doors
- Black Rally Stripes And some Great Bling !

I'm looking for a conservative 450hp at the rear-wheels.

I'll keep you informed...

- -

[JimGnitecki]

Genaris: This is actually a WONDERFUL outcome.

Note that your torque cruve reaches maximum by 4000 rpm but also does not begin falling off until 5700 rpm! That is EXCELLENT breathing - gaood enough that I am surprised to see that you did not list ported or cleaned up heads in your mods.

450 rwhp on Reese's dyno is excellent, as Reese does not inflate his numbers via dyno technique to satisfy a client's ego. These are what you call honest numbers. If you see better than 450 rwhp with the mods you have done, I would suspect an optimistic dyno.

I am impressed that this engine can handle 0.612 valve lift. Are the pistons flattop or do they have clearance cutouts for the valves? I think it is the valve lift that is giving this very fine torque curve.

I know you are probably wondering why the torque curve, and therefore hp curve, fall off so much at low rpm. This is, I am almost certain, a result of moment of intertia and hi stall torque converter effects.

On an inertia type dyno, which Reese's Dynojet is, the powertrain accelerates up VERY quickly during the dyno run, and a LOT of powewr is diverted to spinning up heavy rotating components. On the dyno in 3rd gear, the entire run probably took maybe 4 to 5 seconds. On the street in 3rd gear, it would take much longer.

The hi stall torque converter burns up a lot of power into HEAT at rpm below its stall point. And, with your engine combo being as strong as it is, that stall point is almost surely no longer the 2600 to 2800 it was designed for. Some people "lock" the torque converter for dyno runs, but I think that could be pretty hard on the lockup surfaces, and would also tend to promote detonation at lower rpm.

All in all, if I were you, I would be very proud of this outcome. It's darn good. Now, put a set of really free breathing heads on there, and watch the results skyrocket again at high rpm. Your pistons and rods are forged, and I am surely assuming you chnaged to high quality rod bolts in the process, so this combo is pretty robust.

Nice engine.

Jim G

[Genaris]

The pistons are flattop and they have clearance cutouts for the valves. I am happy with the tune, I just still have that hesitation at idle. Is it just me or is it just the nature of the beast? by the way, I've heard I have about 22% loss of power through my drive train. (20% for auto and 2% for 4.10) Does that include the stall converter? what is your best guessimation on the HP I have at the crank? thanx!

[JimGnitecki]

The 22% total loss figure is pretty much right on.

Since you have 450 at the wheels, your peak power at the crank is probably 577.

Note that this is 577 crank hp AFTER the supercharger has stolen some of the power it created to run itself. I don't remember what the power required to run the blower on the 6.0 liter engines is, but on the 5.3 liter it is about 66 hp or so at peak rpm.

So, you are creating about 640 crank hp after internal engine friction and pumping losses.

This is why I asked about the connecting rods bolts. You have good pistons and rods, so the connecting rod bolts are the key. I am hoping that Reese used some good aftermarket ones, like ARP.

These engines are VERY responsive to simple mods, but as 2005SSR6speed and his partner are discovering, the rest of the SSR was not designed for handling gobs of power (cruiser, not hotrod). As long as you don't run slicks or other incredibly sticky rubber on the rear, you should be ok.

Jim G

[Genaris]

Reece didn't build my motor, just tuned it and I did use stock bolts, but I am not worried.I'm not going to drag this thing. It is just a toy, I will boost it whenever I get the chance, but my mechanic who put it together for me is pretty good. It something "breaks" so be it, it is part of the nature. I am done with my build for now and I'm just going to enjoy my ride...........at least until my chin spoiler arrives.........................................................