Discussion
Cammed and chipped ls7's with some nice internals are 'off the shelf' at 600-650 hp and they should be pretty reliable at that for a reasonable time. After that power level you could strap on a tubby or two and use lowish boost. Or to run higher boost you could drop down to a 402 which having less swept volume would allow a lower compression ratio to be used.
Gulf -LS7 said:
Wilder said:
I dont agree with the above statement.
My engine is an SBC, and is a special custom built order from the block up (4 bolt with splayed main caps).
Not all SBC, even high power ones are going to self destruct, as so much depends on the quality and preparation of the engine build, along with the careful matching of the componant parts.
Yes, it will require more checking of course, but if its done with precision and a skilled builder, it should last.
The LS7 requires some serious modifications to get anywhere near 720 bhp, and the cost is simply prohibitive unless your willing to spend around £25K, and that, I believe is maybe why Shaun considered the SBC as an option.
Im sorry but it will not cost 25k to fit an Ls over a SBC, a LS3 with 600bhp has just been sold on PH for 5.5k thats cheaper than you can build a SBC for with a similiar BHP. It runs efi as standard a dry sump etc etc. If i knew what i do now when i bought my GTR i would never have bought a car with SBC, especially a SBC over 500bhp!!My engine is an SBC, and is a special custom built order from the block up (4 bolt with splayed main caps).
Not all SBC, even high power ones are going to self destruct, as so much depends on the quality and preparation of the engine build, along with the careful matching of the componant parts.
Yes, it will require more checking of course, but if its done with precision and a skilled builder, it should last.
The LS7 requires some serious modifications to get anywhere near 720 bhp, and the cost is simply prohibitive unless your willing to spend around £25K, and that, I believe is maybe why Shaun considered the SBC as an option.
Edited by Wilder on Sunday 30th November 19:05
I think the items in question include the cast pistons (in the L7) and the con rods, but Im sure Jeff S, Builder or Boosted can explain the required mods and likely costs to get 720 bhp from an LS7 far better than I can.
I agree the LS3 is a great engine, and would be a far better bang for the buck.
Boosted LS1 said:
Cammed and chipped ls7's with some nice internals are 'off the shelf' at 600-650 hp and they should be pretty reliable at that for a reasonable time. After that power level you could strap on a tubby or two and use lowish boost. Or to run higher boost you could drop down to a 402 which having less swept volume would allow a lower compression ratio to be used.
Thanks, very interesting indeed. What would be approx costs for LS7 alone then additionally with strap ons? Originally, what I really wanted was a GTR 720 SBC 'already to go' within my budget, although but before I make the jump would look at all other alternatives for sure. It seems several TVR's are going down this route too.shaunsmith said:
Boosted LS1 said:
Cammed and chipped ls7's with some nice internals are 'off the shelf' at 600-650 hp and they should be pretty reliable at that for a reasonable time. After that power level you could strap on a tubby or two and use lowish boost. Or to run higher boost you could drop down to a 402 which having less swept volume would allow a lower compression ratio to be used.
Thanks, very interesting indeed. What would be approx costs for LS7 alone then additionally with strap ons? Originally, what I really wanted was a GTR 720 SBC 'already to go' within my budget, although but before I make the jump would look at all other alternatives for sure. It seems several TVR's are going down this route too.
You could run a boosted SBC at a 'true' 720hp with a more long term outlook.
The problem is getting one...most are one-offs apart from the odd A/S version. So unless your man is geared to that extent, with the initial build and ongoing support...thats probably a no-go too.
N/A SBC's at true big Hp are just not going to be user friendly. If you sat and studied the relatively small components (eg roller lifter axles) that are expected to compress 500+LBS of valve spring at 7000+RPM or happily sit for a week, maybe month or two, holding it partially or fully compressed....you probably wouldn't even consider it viable, never mind chuck a ten grand gamble at it!
True big Hp SBC's are more for mechanical moles.
If it were top gear, Clarkson would have dissappeared with his LS whilst May was happily coaxing his tinkered SBC along somewhere.
Just like the old Ford X-Flow, still great and very useable, however.... better stuff will eventually take its place!
The problem is getting one...most are one-offs apart from the odd A/S version. So unless your man is geared to that extent, with the initial build and ongoing support...thats probably a no-go too.
N/A SBC's at true big Hp are just not going to be user friendly. If you sat and studied the relatively small components (eg roller lifter axles) that are expected to compress 500+LBS of valve spring at 7000+RPM or happily sit for a week, maybe month or two, holding it partially or fully compressed....you probably wouldn't even consider it viable, never mind chuck a ten grand gamble at it!
True big Hp SBC's are more for mechanical moles.
If it were top gear, Clarkson would have dissappeared with his LS whilst May was happily coaxing his tinkered SBC along somewhere.
Just like the old Ford X-Flow, still great and very useable, however.... better stuff will eventually take its place!
Edited by 738 driver on Monday 1st December 10:20
Mike, can you tell us exactly whats involed cost wise to get 700+bhp out of an LS7 compared to say the LS3?
I believe theres a number of things that make it an expensive proposition, but I would be interested in a Pros take on whats involved.
Many thanks
I believe theres a number of things that make it an expensive proposition, but I would be interested in a Pros take on whats involved.
Many thanks
Edited by Wilder on Monday 1st December 01:26
A lot of people seem to think there is some kind of holly grail around the LS7 and as such stupid over inflated prices can be charged...
That simply is not the case, there are LS7 engine suppliers/builders who will build you a engine for reasonable money in fact less than an equivalent SBC. It may even come wiith a proper warrenty!!
That simply is not the case, there are LS7 engine suppliers/builders who will build you a engine for reasonable money in fact less than an equivalent SBC. It may even come wiith a proper warrenty!!
Wilder said:
Mike, can you tell us exactly whats involed cost wise to get 700+bhp out of an LS7 compared to say the LS3?
I believe theres a number of things that make it an expensive proposition, but I would be interested in a Pros take on whats involved.
Many thanks
For either engine you'd want to fit forged pistons and rebalance the crank. Then it's normal to change the camshaft and fit dual springs to the heads and maybe change the valves. After that you would need to change the tune in the GM ecu or buy another brand that's mappable like an Omex or DTA. I think 700 hp is going to be very expensive, think downdrafts as well and I personally wouldn't aim that high in a n/a configuration. 600-650 seems to be the norm. £14-15k for a ls7 plug and play package (600-650 hp) if you don't have an engine or loom/ecu etc. Obviously a lot less if you already have the engine. I'm talking about a genuine ls7 and not a 427 made from other parts.I believe theres a number of things that make it an expensive proposition, but I would be interested in a Pros take on whats involved.
Many thanks
Edited by Wilder on Monday 1st December 01:26
ETA. An ls3 is a smaller capacity engine and it's parts aren't quite as good as with an ls7. It's got budget heads, rods etc but would still be a good platform and the money saved buying it could be used towards forced induction as you could lower it's compression a bit more easily then on the ls7.
Edited by Boosted LS1 on Monday 1st December 09:37
Boosted LS1 said:
Wilder said:
Mike, can you tell us exactly whats involed cost wise to get 700+bhp out of an LS7 compared to say the LS3?
I believe theres a number of things that make it an expensive proposition, but I would be interested in a Pros take on whats involved.
Many thanks
For either engine you'd want to fit forged pistons and rebalance the crank. Then it's normal to change the camshaft and fit dual springs to the heads and maybe change the valves. After that you would need to change the tune in the GM ecu or buy another brand that's mappable like an Omex or DTA. I think 700 hp is going to be very expensive, think downdrafts as well and I personally wouldn't aim that high in a n/a configuration. 600-650 seems to be the norm. £14-15k for a ls7 plug and play package (600-650 hp) if you don't have an engine or loom/ecu etc. Obviously a lot less if you already have the engine. I'm talking about a genuine ls7 and not a 427 made from other parts.I believe theres a number of things that make it an expensive proposition, but I would be interested in a Pros take on whats involved.
Many thanks
Edited by Wilder on Monday 1st December 01:26
ETA. An ls3 is a smaller capacity engine and it's parts aren't quite as good as with an ls7. It's got budget heads, rods etc but would still be a good platform and the money saved buying it could be used towards forced induction as you could lower it's compression a bit more easily then on the ls7.
Edited by Boosted LS1 on Monday 1st December 09:37
I've not costed it but it would be less. Ls3's/L98's seem to cost peanuts from Oz at the moment, half the cost of an ls7. Both engines would need new pistons and a rebalance. Ls3 turbo could keep the stock camshaft and valvetrain. In fact a lot of it could remain stock. Add the cost of turbo's £2k, manifolds and exhaust revisions etc £2k. Or the ls3 could use low boost and leave the engine completely stock inside. That would be way cheaper then a hopped ls7. What's more a stock engine almost becomes disposable at the prices they command at present.
ETA, to say L98's as these are the bargain engines at the moment.
ETA, to say L98's as these are the bargain engines at the moment.
Edited by Boosted LS1 on Monday 1st December 12:00
Normally a few engines for sale hear.
http://www.my105.com.au/default3.asp?id=5477
most of the high HP SBC engines are ex Australian V8 supercar engines. These are 96 octane 7k rpm engines. Longest race for the season is 1000km. Don’t know of any other 650hp engines that would last for a 1000km at race pace. Given a freshen up its probably reasonably god value for money. Haven’t looked what the AU exchange rate is today, to depressing probably.
http://www.my105.com.au/default3.asp?id=5477
most of the high HP SBC engines are ex Australian V8 supercar engines. These are 96 octane 7k rpm engines. Longest race for the season is 1000km. Don’t know of any other 650hp engines that would last for a 1000km at race pace. Given a freshen up its probably reasonably god value for money. Haven’t looked what the AU exchange rate is today, to depressing probably.
Boosted LS1 said:
I've not costed it but it would be less. Ls3's seem to cost peanuts from Oz at the moment, half the cost of an ls7. Both engines would need new pistons and a rebalance. Ls3 turbo could keep the stock camshaft and valvetrain. In fact a lot of it could remain stock. Add the cost of turbo's £2k, manifolds and exhaust revisions etc £2k. Or the ls3 could use low boost and leave the engine completely stock inside. That would be way cheaper then a hopped ls7. What's more a stock engine almost becomes disposable at the prices they command at present.
I am immediately interested for a LS7 with 600-650 hp for less £14k-15k...
I don't know LS3. Is it a good solution ? Advices wellcome.
What about my actual trans ? (Getrag 6 speeds delivered by the Ultima Factory).
shaunsmith said:
Boosted LS1 said:
Cammed and chipped ls7's with some nice internals are 'off the shelf' at 600-650 hp and they should be pretty reliable at that for a reasonable time. After that power level you could strap on a tubby or two and use lowish boost. Or to run higher boost you could drop down to a 402 which having less swept volume would allow a lower compression ratio to be used.
Thanks, very interesting indeed. What would be approx costs for LS7 alone then additionally with strap ons? Originally, what I really wanted was a GTR 720 SBC 'already to go' within my budget, although but before I make the jump would look at all other alternatives for sure. It seems several TVR's are going down this route too.You can see it here:
http://www.knightracingservices.co.uk/chevengines....
An LS7 costs $14500 (but with exchange rates there are some cheaper ones now in the UK) let's say £8.5k
All the mods to the engine, Motec ECU, Kinsler inlet, wiring loom etc with dyno time will be about £17k
Decent exhaust system £3500
So a genuine 700bhp LS7 engine will cost circa £30k
Much much cheaper if you can settle for 550bhp and stick with stock engine.
You will need additional bits to fit in the car or to change from SBC - adaptor plate, air con, alternator, mounts, cluch and flywheel, plumbing, dry sump tank, fuel pumps etc etc
Hi Craig. Don't worry my engine internals are good for a couple of turbos and 1000hp. I did start wanting a turbo engine but was talked out of it.
Most sensible advice suggests that 650 - 700 is sufficient in an Ultima and best to focus on a decent gearbox to gain performance after that. I would still like to fit a sequential box but that's mega money.
The main problem that I could see with a turbo engine is scrubbing torque. My engine has been tuned to reduce torque as far as possible and it still has over 500 ft/lb at 3000 rpm.
How is your build coming along?
Regards
David
I did start wanting a turbo engine but was talked out of it. Most sensible advice suggests that 650 - 700 is sufficient in an Ultima and best to focus on a decent gearbox to gain performance after that. I would still like to fit a sequential box but that's mega money.
The main problem that I could see with a turbo engine is scrubbing torque. My engine has been tuned to reduce torque as far as possible and it still has over 500 ft/lb at 3000 rpm.
How is your build coming along?
Regards
David
Edited by XTR2Turbo on Monday 1st December 21:29
Gassing Station | Ultima | Top of Page | What's New | My Stuff