LS7 on the Dyno
Discussion
Haven't seen the dyno sheet yet, but here are the results. And she was making 400 ft/lbs at 2500!!! All stock. Manifold spun 180 degrees with a mechanical T/B and dyno headers.
rpm----tq---hp
3000--455--260
3500--467--311
4000--504--383
4500--526--451
5000--529--503
5500--512--537
6000--480--548
6100--472--548
6200--463--547
6300--454--544
6400--445--543
rpm----tq---hp
3000--455--260
3500--467--311
4000--504--383
4500--526--451
5000--529--503
5500--512--537
6000--480--548
6100--472--548
6200--463--547
6300--454--544
6400--445--543
d3vine, have you seen the W2W stwin supercharger kit? uses twin Rotex blowers (can remember which ones) and can make over 1000bhp! 
oh and costs $5K
they are putting it on one of thier boost ready 402 LS2 and i think they have seen 950bhp from it already! be reaaaallllyyyy nice on a LS7 with some low comp pistons!
builder, thoes numbers are ace!
thanks Chris.
oh and costs $5K they are putting it on one of thier boost ready 402 LS2 and i think they have seen 950bhp from it already! be reaaaallllyyyy nice on a LS7 with some low comp pistons!
builder, thoes numbers are ace!
thanks Chris.
builder said:
Will you have MAF?
The BigStuff3 ECU and harness installation was successful tonight. I don't have the dyno sheet yet, but she made 548 HP @ 6100 and 529 ft/lbs from 4.7 to 4.9k. If my notes are correct, she made 400 ft/lbs at 3k! All standard-corrected numbers. WooooHoooo!
Thanks Scott, nice numbers to
Will you send me a copy sheet for comparisons later please. Boosted.
LS7 available from a UK supplier! mentioned here: www.totalkitcar.com/news.php
www.lspower.co.uk/
I'm a long way from engine selection but if they honour the warranty and there are no serious issues with installing it in the ultima (lets see how builder gets on) then I'll be paying them (literally) a visit.
505 injected horses, cool.
To add to the confusion I had my first ls7 some 9 months ago, probably before the official release so GD definately weren't the first UK supplier to have one. Same goes for my ls1's etc.
Also there will be some confusion with their link.www.lspower.co.uk. Look at this similar link www.ls1-power.com. A project I've been closely involved with engine build wise which will be getting blown ls7 power later on This rangie has covered over 20k miles and we've got it running on the Gems ecu. Overfinch, eat your heart out
Boosted.
. Same goes for my ls1's etc. Also there will be some confusion with their link.www.lspower.co.uk. Look at this similar link www.ls1-power.com. A project I've been closely involved with engine build wise which will be getting blown ls7 power later on
This rangie has covered over 20k miles and we've got it running on the Gems ecu. Overfinch, eat your heart out Boosted.
Thats useful to know. I want to see how builder gets on with the install in the ultima, especially with mounting, aftermarket dry sumping, engine mapping, accessories and exhaust (with a cataclysmic converter) to sort out. Not trying to put you off builder but its certainly virgin territory.
Please please please I hope it goes in without problems, its either this or a 350-400 SBC. As a first engine I don't really want a twitchy-thirsty-tweaked-SBC and the LS7 is high on my shopping list (although it aint cheap after adding all the bits up).
I go to sleep now.
>> Edited by mhussa on Friday 20th January 00:54
Please please please I hope it goes in without problems, its either this or a 350-400 SBC. As a first engine I don't really want a twitchy-thirsty-tweaked-SBC and the LS7 is high on my shopping list (although it aint cheap after adding all the bits up).
I go to sleep now.
>> Edited by mhussa on Friday 20th January 00:54
Regarding the fitment of the LS7, I don't anticipate too many issues. The LS7 is an evolution in performance, but still in the LSx family. It's the same form-factor as previous LSx engines, so, essentially, fitment has already been done with an LS1 or LS6 (aside from the dry-sump).
The accessory brackets are the same as the C5/C6 Corvette, so that shouldn’t be very challenging. Low mounts are available for right-side A/C and left-side ALT.
The exhaust flange is the same as the LS2, but I haven't really thought about a design yet. I might make a few sets when I do mine, if anyone is interested. They should be very affordable...by comparison.
The ECU and harness is available from a company called BigStuff3 (BS3), which is a sequential, speed density (no MAF) or Alpha-N system. For the near term, it can only be purchased from Wheel-2-Wheel Powertrain, as they have helped in the development and have an exclusive for a short stint. The BS3 system is highly regarded by folks with forced induction.
Other companies are working on cracking and reprogramming the stock PCM. I have the stock PCM as well. Nothing available yet, but four or five companies have said they are into the box and learning it's language. That I know of, only one of these companies is working on a "stand-alone" setup using the stock PCM.
Regarding boost, it probably wouldn't be a good idea to push the stock, cast pistons. The OEM is already building a forged set and they are available in the aftermarket now.
Engine mods for the GTR: The intake manifold has been spun 180 degrees. This was not too hard. The oil pressure sender was removed, the boss cut down, bored and tapped for a 3/8 plug. An engine plug was removed and he sender was put in it's place...a direct fit. A crank vent in the valley cover was rerouted using a 10" piece of AL tube. An aluminum fitting was designed to replace the stock oil hoses with -12AN braided lines. A C5 Vette oil take-off was fit for -12 lines to an oil cooler. I will drop a thermostat in with that.
The BS3 system is designed to use a mechanical throttle body. The stock LS7 unit is "fly-by-wire", which means the peddle requires electronics. A mechanical T/B was fit to the intake and brackets were designed for the cables. A 1.6" spacer was required between the T/B and manifold. The T/B was also mounted up-side-down because the blade opens opposite to the stock unit...which changes flow dynamics.
All said, no show stoppers yet!
-- Scott
The accessory brackets are the same as the C5/C6 Corvette, so that shouldn’t be very challenging. Low mounts are available for right-side A/C and left-side ALT.
The exhaust flange is the same as the LS2, but I haven't really thought about a design yet. I might make a few sets when I do mine, if anyone is interested. They should be very affordable...by comparison.
The ECU and harness is available from a company called BigStuff3 (BS3), which is a sequential, speed density (no MAF) or Alpha-N system. For the near term, it can only be purchased from Wheel-2-Wheel Powertrain, as they have helped in the development and have an exclusive for a short stint. The BS3 system is highly regarded by folks with forced induction.
Other companies are working on cracking and reprogramming the stock PCM. I have the stock PCM as well. Nothing available yet, but four or five companies have said they are into the box and learning it's language. That I know of, only one of these companies is working on a "stand-alone" setup using the stock PCM.
Regarding boost, it probably wouldn't be a good idea to push the stock, cast pistons. The OEM is already building a forged set and they are available in the aftermarket now.
Engine mods for the GTR: The intake manifold has been spun 180 degrees. This was not too hard. The oil pressure sender was removed, the boss cut down, bored and tapped for a 3/8 plug. An engine plug was removed and he sender was put in it's place...a direct fit. A crank vent in the valley cover was rerouted using a 10" piece of AL tube. An aluminum fitting was designed to replace the stock oil hoses with -12AN braided lines. A C5 Vette oil take-off was fit for -12 lines to an oil cooler. I will drop a thermostat in with that.
The BS3 system is designed to use a mechanical throttle body. The stock LS7 unit is "fly-by-wire", which means the peddle requires electronics. A mechanical T/B was fit to the intake and brackets were designed for the cables. A 1.6" spacer was required between the T/B and manifold. The T/B was also mounted up-side-down because the blade opens opposite to the stock unit...which changes flow dynamics.
All said, no show stoppers yet!
-- Scott
Thanks thats excellent info Scott (keep it coming).
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www.airtightinteractive.com/simpleviewer/
I came across this freeware flash album thingy recently. A very nice way of organising online photo's (and best of all its free).
www.airtightinteractive.com/simpleviewer/
d3vine said:
How difficult would it be to obtain 850hp and about the same about of torque with twin rotrex supercharger on the LS7? I was told that it difficult to obtain large amount of hp from the superchargers due to the LS7's cast piston. Is this true?
The cast pistons are cheap imo but not disimilar to other lsx pistons and we know other lsx's can take small amounts of boost quite happily so long as the mapping's sorted. Detonation will break the stock pistons and probably crack a liner at the same time. I think 850 hp is to high a figure for the stock pistons.
Also, as Builder says forged pistons are available but imo the engine would need rebalancing as the forged pistons weigh a bit less then the cast items. You may as well build up an engine from scratch as opposed to tearing one down and rebuilding it.
Boosted.
d3vine said:
How difficult would it be to obtain 850hp and about the same about of torque with twin rotrex supercharger on the LS7? I was told that it difficult to obtain large amount of hp from the superchargers due to the LS7's cast piston. Is this true?
i think its doable mate. might take a bit of a build but doable!
here is a link that you may find useful www.ls1tech.com/forums/forumdisplay.php?f=80
there is a company on there called Katech that already has forged pistons (high and low comp) for the LS7.
W2W also offer a twin rotex kit wich fits the LSx engines so should fit the LS7 right??? it cost $5K (about £3.2K). the good thing about the LS7 is the heads are ace out the box so nothing needed there. you could use the original intake. for the intercooling i would use a chargecooler(s). could mount them above the rocker covers. headers would have to be custom.
ECU, well im not sure. any ideas?????
Chris.
There is no doubt the GTR is a real racecar. However, it's also a street-legal car that I plan on driving A LOT. My goal is to have a dependable, wicked-fast street car that can cruise 1,000 miles on pump gas without having to carry too many spare parts. It's also been my experience that the more tweaking, the shorter the lifespan.
And, the GTR is relatively expensive. I have enough $$,$$$ in the budget to build it right, but not enough to build it twice! This build is deviating from a "stock" config by virtue of the engine and a host of electronics, but I am not using exotic or ultra-high-performance parts. This isn't a build for "maximum effort".
"Dependable" is important, as is longevity. My guess is, with huge HP and torque, the clutch/trans/diff won't last as long and I don't want to rebuild them every other year. The LS7, as it ships from GM, can probably go 70k - 100k miles without a rebuild. That's one of the real benefits of a factory lump, aside from the initial warranty.
When it’s rebuild time, I will likely go for forged, low-comp pistons and probably a centrifugal supercharger and 6-8 psi. This should boost the 548 hp to 700, or more.
Who knows? Maybe by then, there will be another engine available that will fit the GTR (maybe a hybrid) and I will put the LS7 in my Impala.
I know for a fact that the LS9 is in testing. Don’t ask as I am sworn to secrecy. 
-- Scott
And, the GTR is relatively expensive. I have enough $$,$$$ in the budget to build it right, but not enough to build it twice! This build is deviating from a "stock" config by virtue of the engine and a host of electronics, but I am not using exotic or ultra-high-performance parts. This isn't a build for "maximum effort".
"Dependable" is important, as is longevity. My guess is, with huge HP and torque, the clutch/trans/diff won't last as long and I don't want to rebuild them every other year. The LS7, as it ships from GM, can probably go 70k - 100k miles without a rebuild. That's one of the real benefits of a factory lump, aside from the initial warranty.
When it’s rebuild time, I will likely go for forged, low-comp pistons and probably a centrifugal supercharger and 6-8 psi. This should boost the 548 hp to 700, or more.
Who knows? Maybe by then, there will be another engine available that will fit the GTR (maybe a hybrid) and I will put the LS7 in my Impala.
I know for a fact that the LS9 is in testing. Don’t ask as I am sworn to secrecy. -- Scott
G Man said:Yes, but the BS3 system, engine wiring harness, dyno tuning, turning the intake, oil fittings, and throttle body spacer were free for letting them use my engine. I will have to buy a cable T/B, make the bracket for the cables, and I paid shipping one way. That's a hard deal to pass up. Officially, the BS3 doesn't perform traction control. But, I may not need to purchase anything extra for that function. I really like the missed-shift protection of the Racelogic.
Scott
Did you consider a Motec system, I was thinking that as the LS7 is a fly by wire throttle and a Motec M800 can do FBW it should fit into an Ultima.
With 12 degree heads IIRC is the engine taller than a SBC
Not sure of the exact height on the LS7. My engine should be back home in about a week. I am going to start moving into the new shop and unpacking the crate today. (I can't believe it!) One of the first things on the to-do list is to test-fit the engine and give the dimensions to my trans builder so he can make the correct length bell housing. I can pull some height measurements, too.
BTW, today starts the pilot production of the LS9, which is an LS7 with a supercharger. Those engines are for the '08 Z06 "Blue Devil". That engine may be a little taller still, but what a beast! Hope to see some power numbers next week...
jellison said:
The ECU on the vettes LS range is the NUT - Mega Millions invested in it by chevy - highly tuneable - After market ECU a total waste of time (IMHO).
Not quite so Jon. Sure GM spent a lot on their ecu. The ls7 ecu is a pain in the butt from what I hear and the after market stuff LS7 stuff is probably going to be plug and play, plus I doubt it will support traction control without abs systems. This is where an aftermarket ecu could make major in roads. Motec, DTA, Autronic all offer comprehensive systems and I bet they spent plenty over the years. Australia seems to be the place for ecu's and has been for a long time. I have GM ecu's here but for my own projects I'm still open minded.
Boosted.
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