Living with 700 horses
Discussion
A few notes on my recent fun with a 700hp LS 7 may be of interest. (yes I’m bored looking out at the snow) This is my third Ultima, with 2 SBC and 2 LS 7 engines so this is real life experience not netcrap. Engine is rated in BHP (British Horse Power
)
Peter Knight built the engine with the emphasis on drivability. This drivability isn’t just for road use but is perfect for competition use – great floods of torque rushing at you out of corners is a menace and just forces you off the gas to avoid a spin. Drivability and Controllability. 4 barrel throttle body (progressive primary/secondary) Motec with traction control, cable throttle, Jesel etc.
Lots of interesting info about the engine – won’t bore you with most of it. An important thing is that the so called 1000 cfm throttle bodies don’t flow anything like their claim. Extensive flow bench and machining work required to get up to spec. Also, despite supposedly being cnc machined my heads flowed differently to Swiss Toni’s and needed machining and more flow bench work.
Comparison with the standard LS 7 :- The standard motor had FBW and GM ecu and for a road car perhaps provides a more “exciting” drive than Motec/cable because the ecu control gives a more immediate throttle response from lower revs. However in the wet this works against you as you tend to spin up double quick. My guess is this quick response would be really horrid with the 700hp. The GM “interferes” under light throttle transitions and can be slightly irritating.
Comparison with the 580hp sbc X8 GTR:- I suppose that the best analogy I can draw with X8 is that it was a bit like a faithful Labrador dog – never going to bite you but sure as f**k never going to chase a rabbit …… . Irrespective of the reality of power claims the difference between X8 and the SS700 is huge and feels more than the figures would suggest. Getting the 700 on the cam is a truly life affirming experience.
The LS700 is just easy and progressive. Nice and gentle to start with and just builds and builds. However, towards the top end it builds into something quite evil… At Brands Hatch rushing out of Druids in third was smooth and easy – no lurid tail out stuff or drama. (partly due to the ATB diff) Given a full hole the pace into Paddock would have been truly sphincter clenching..
.. Because the motor is controllable I haven’t needed the Motec traction control in the dry. However, competitors have told me it’s an absolute lifesaver in the wet.
Curiously, a really nice daily driver was the modest output hydraulic tappet sbc in the GTR GAZ car. (apart from the w@nky carb )
Forget all the pub talk gibberish, trying to access anything like all of 700 BHP at Brands or your favourite country route is a really intimidating experience and in truth may not be possible for ordinary drivers.
)Peter Knight built the engine with the emphasis on drivability. This drivability isn’t just for road use but is perfect for competition use – great floods of torque rushing at you out of corners is a menace and just forces you off the gas to avoid a spin. Drivability and Controllability. 4 barrel throttle body (progressive primary/secondary) Motec with traction control, cable throttle, Jesel etc.
Lots of interesting info about the engine – won’t bore you with most of it. An important thing is that the so called 1000 cfm throttle bodies don’t flow anything like their claim. Extensive flow bench and machining work required to get up to spec. Also, despite supposedly being cnc machined my heads flowed differently to Swiss Toni’s and needed machining and more flow bench work.
Comparison with the standard LS 7 :- The standard motor had FBW and GM ecu and for a road car perhaps provides a more “exciting” drive than Motec/cable because the ecu control gives a more immediate throttle response from lower revs. However in the wet this works against you as you tend to spin up double quick. My guess is this quick response would be really horrid with the 700hp. The GM “interferes” under light throttle transitions and can be slightly irritating.
Comparison with the 580hp sbc X8 GTR:- I suppose that the best analogy I can draw with X8 is that it was a bit like a faithful Labrador dog – never going to bite you but sure as f**k never going to chase a rabbit …… . Irrespective of the reality of power claims the difference between X8 and the SS700 is huge and feels more than the figures would suggest. Getting the 700 on the cam is a truly life affirming experience.
The LS700 is just easy and progressive. Nice and gentle to start with and just builds and builds. However, towards the top end it builds into something quite evil… At Brands Hatch rushing out of Druids in third was smooth and easy – no lurid tail out stuff or drama. (partly due to the ATB diff) Given a full hole the pace into Paddock would have been truly sphincter clenching..
.. Because the motor is controllable I haven’t needed the Motec traction control in the dry. However, competitors have told me it’s an absolute lifesaver in the wet.Curiously, a really nice daily driver was the modest output hydraulic tappet sbc in the GTR GAZ car. (apart from the w@nky carb )
Forget all the pub talk gibberish, trying to access anything like all of 700 BHP at Brands or your favourite country route is a really intimidating experience and in truth may not be possible for ordinary drivers.
Nice words and pleasant description. I can imagine that driving a 700hp car weighing around 1000kg tops on an open road needs a certain amount of "training", otherwise you will certainly miss the bend in the distance and have travelled through the hedge before knowing what happened....
That's some great info after hearing others saying that you don't really need that power.
Mind you I'm really not the average person when it comes to horsepower either. My mates say I'm the only idiot they know that hop on an R1 and say it's too slow and want to modify it. My R1 makes 154rwhp now
Plus when it comes to cars at the moment I have a BMW E46 M3 with a built motor turboed making 520rwhp @ 14psi and a Ford Escort Mk2 that's a tube frame chassis with a 2JZ in it making 600rwhp @ 20psi and weighs 900kg and if I can hold that thing relatively straight and keep it off the wall I don't see a 700bhp Ultima (which will most likely only make 550rwhp) an issue to control.
Mind you I'm really not the average person when it comes to horsepower either. My mates say I'm the only idiot they know that hop on an R1 and say it's too slow and want to modify it. My R1 makes 154rwhp now
Plus when it comes to cars at the moment I have a BMW E46 M3 with a built motor turboed making 520rwhp @ 14psi and a Ford Escort Mk2 that's a tube frame chassis with a 2JZ in it making 600rwhp @ 20psi and weighs 900kg and if I can hold that thing relatively straight and keep it off the wall I don't see a 700bhp Ultima (which will most likely only make 550rwhp) an issue to control.Rusti Evo said:
....X8...was a bit like a faithful Labrador dog – never going to bite you but sure as f**k never going to chase a rabbit ....
WOOF!!!GnaaarrH
One thing to say to you Rusti....
The better you get, the less power you need!!!
You going to Brands on the 11th? I'll hunt ya down in the MR2!!
Just joshin'. Like these sort of posts from folk who can actually talk about the comparisons with authority. Sounds a beastie....
Pleaaaaassssee can I have a go????
spatz said:
so rusti, that sounds serious, what gearbox can hold all of that power, and do you have the rose joint suspension in the car ?
After speaking to Ted today he thinks a G50 with have no issue holding the power for years. He said in a Porsche it won't do it but the Ultima being so much lighter it shouldn't be an issuemmmmm..... my supercharged LS2 has a very similar performance to an LS7 and I agree, it is more than adequate in an Ultima. On the road it is outrageous.
I drove Jeff Schwartz's 1000hp monster 400 miles on the Hot Rod Power Tour last year...... whilst immensely entertaining, I dont think I got the pedal past 1/2 way, even on the expressway.
Having said that, there is a Twin Turbo project in the pipeline, not an Ultima, but you guys might still be interested.....stay tuned.
I drove Jeff Schwartz's 1000hp monster 400 miles on the Hot Rod Power Tour last year...... whilst immensely entertaining, I dont think I got the pedal past 1/2 way, even on the expressway.
Having said that, there is a Twin Turbo project in the pipeline, not an Ultima, but you guys might still be interested.....stay tuned.
Stuart
With respect you havent kept any of them for long enough to really understand them....
IMO it isnt the engine that impressive in your new car its whats around it!!!! I see lots of smoke being blown in Petes direction but not much being blown where it should be going.
I would love to see your new weapon used in anger as its mightily impressive, so when can we all see it happen?
With respect you havent kept any of them for long enough to really understand them....
IMO it isnt the engine that impressive in your new car its whats around it!!!! I see lots of smoke being blown in Petes direction but not much being blown where it should be going.
I would love to see your new weapon used in anger as its mightily impressive, so when can we all see it happen?
sorry forgot to say, id love to see your cam specs? They didnt make a lot of sense to me but that doesnt mean a lot!! Weve had a lot of fun with cams in the last 12 months(thanks 738 for your help) and i must admit im trying my very best to get my head round what does and does not work.
LuckyP said:
Rusti Evo said:
....X8...was a bit like a faithful Labrador dog – never going to bite you but sure as f**k never going to chase a rabbit ....
WOOF!!!GnaaarrH
One thing to say to you Rusti....
The better you get, the less power you need!!!
You going to Brands on the 11th? I'll hunt ya down in the MR2!!
Just joshin'. Like these sort of posts from folk who can actually talk about the comparisons with authority. Sounds a beastie....
Pleaaaaassssee can I have a go????
Just kidding....Apologies chap, no criticism of X8 intended - just sort of came out that way - just having fun and talking forum b
ks.As we both know vehicle dynamics, setup and driver ability are where the real gains are to be made.
Best check the mirrors on Bottom Straight I think X18 could inhale the MR2..
From an historic point of view I wished I had discovered the joys of the Kenlowe pre-heater earlier as I am sure it wouyld have sorted the carb starting faff.
spatz said:
so rusti, that sounds serious, what gearbox can hold all of that power, and do you have the rose joint suspension in the car ?
spatz, Have done a lot of learning over the last 18 months from proper motorsport companies (not the internet "experts") and there are 2 figures for holding capacity.1. The advertised torque figure based on warranty avoidance and customers expectation of reliabilty in everyday use.
2. The maximum design capacity.
For instance the clutch that AP specified has an advertised figure of 550lb/ft and a design max of 825lb/ft. They have advised that in this application we can expect a capacity of somewhere between the 2 - say around 690 ish. Obviously anything beyond their advertised figure is down to us.
Also, the NLT gearbox that we considered has an advertised capacity of only 500lb/ft whereas we know it will survive the horrors of endurance racing with very robust engines. (assuming the components are lifed)so we can assume there is a considerable margin built in.
Gulf LS3 said:
sorry forgot to say, id love to see your cam specs? They didnt make a lot of sense to me but that doesnt mean a lot!! Weve had a lot of fun with cams in the last 12 months(thanks 738 for your help) and i must admit im trying my very best to get my head round what does and does not work.
Howdy Kyle,As you know being involved in a large project you get to encounter all sorts of juicy info. I've no doubt Pete and Eddy would consider some stuff to be confidencial between builder and customer and I wouldn't repeat that. We all need that layer of trust don't we.
Gulf LS3 said:
Stuart
With respect you havent kept any of them for long enough to really understand them....
IMO it isnt the engine that impressive in your new car its whats around it!!!! I see lots of smoke being blown in Petes direction but not much being blown where it should be going.
I would love to see your new weapon used in anger as its mightily impressive, so when can we all see it happen?
Hi Kyle,With respect you havent kept any of them for long enough to really understand them....
IMO it isnt the engine that impressive in your new car its whats around it!!!! I see lots of smoke being blown in Petes direction but not much being blown where it should be going.
I would love to see your new weapon used in anger as its mightily impressive, so when can we all see it happen?
I think you'll find it was Greg thats bigging up Petes engine - the purpose of this little scribble was just to add some real world stuff about engines. Whatever the reality of the smoke and mirrors of engine figures, Petes horses are obviously big ones. I hope I am not speaking out of turn but reliable rumour has it that Greg was running 200+ at Brunters dead easy.
You are right about the car - an engine is just an engine. However, as you know the car is a testament to Steve Smiths skills and dedication to the persuit of quality.
You are also correct about not hanging on to my cars for long enough - its up for sale. Onwards and upwards........
Rusti Evo said:
Gulf LS3 said:
sorry forgot to say, id love to see your cam specs? They didnt make a lot of sense to me but that doesnt mean a lot!! Weve had a lot of fun with cams in the last 12 months(thanks 738 for your help) and i must admit im trying my very best to get my head round what does and does not work.
Howdy Kyle,As you know being involved in a large project you get to encounter all sorts of juicy info. I've no doubt Pete and Eddy would consider some stuff to be confidencial between builder and customer and I wouldn't repeat that. We all need that layer of trust don't we.
I dont want one thanks, i was just interested in why it was used? Poor idle, but with no acceptable top end trade off, why have you only got a 6850 rev limit?
Standard cam has a rock steady 800rpm bottom end with 7100rpm rev limit, makes no sense as i said, or is the 6850 rev limit an extended run in procedure, with 7500rpm to come?
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