Choice of engine
Discussion
How do you decide what engine from American Speed to choose?
There appears to be a large choice!
I am looking for a unit with extreme horse power 600+
Has anyone any apinion on what is best 600/640/720 etc
Also has anyone had any troubles with the units they have bought.
I am in the process of modifying my Ultima which was bought with a 385bhp chevy.
The only decision I have made it will be naturally aspirated!
There appears to be a large choice!
I am looking for a unit with extreme horse power 600+
Has anyone any apinion on what is best 600/640/720 etc
Also has anyone had any troubles with the units they have bought.
I am in the process of modifying my Ultima which was bought with a 385bhp chevy.
The only decision I have made it will be naturally aspirated!
If I was doing another Ultima, I would go for a bog standard 350.
My 535 hp AS gave up the ghost after 6,500 miles. These motors are highly stressed, plus there are issues with cooling (not that Ultimas have cooling problems
)and idling. I'm sure it's not just coincidence that Stig has gone for one in a mild state of tune for his Canam
If you want to track it a lot, then that's a different story!
>> Edited by gtr-gaz on Thursday 11th May 21:32
My 535 hp AS gave up the ghost after 6,500 miles. These motors are highly stressed, plus there are issues with cooling (not that Ultimas have cooling problems
)and idling. I'm sure it's not just coincidence that Stig has gone for one in a mild state of tune for his Canam If you want to track it a lot, then that's a different story!
>> Edited by gtr-gaz on Thursday 11th May 21:32
If I was building a Ultima or buying a second hand, there have to be a more modern engine in it...at least a LS1
So LS2 better .....LS7 best
But also some others will do great like the V8 audi's and more recent BMW
Do yourself a favor and buy a more modern engine, good economy, reliable, and not a oilburner like the SBC engine's and scary storys of lots of oil using AS engines'...
GTRene
So LS2 better .....LS7 best
But also some others will do great like the V8 audi's and more recent BMW
Do yourself a favor and buy a more modern engine, good economy, reliable, and not a oilburner like the SBC engine's and scary storys of lots of oil using AS engines'...
GTRene
there are LOTS of other SBC builders out there that cold build you a bomb prof SBC!
also def look into the LS series of engines! you can pic up big power fr not that much cash! also they are lighter (ally as standard) and ome with EFI and electronic ignition as standard!
thannks Chris.
also def look into the LS series of engines! you can pic up big power fr not that much cash! also they are lighter (ally as standard) and ome with EFI and electronic ignition as standard!
thannks Chris.
steve_d said:
Go as far down the list as you can without your credit card catching fire.
Steve
how true! Bear in mind that with these engines you will also have to factor in a new set of exhaust headers for the 18 degree heads. I think that adds £4k+ to the bill
Speaking from experience, its very tempting to go for the biggest, shiniest, most powerful engine - but you really need to consider how you'll use the car.
I still maintain that even a stock .350 in an Ultima is easily enough power on the road and lets face it, you can tell people that it has 1000hp and they'll believe you. It's just pub bragging rights.
So if you want to rag it up a drag strip, go for monster power. But it won't like trickling about in traffic.
If you want a trackday car, then go for the 450hp+ units. Reliable horsepower, but you'll still need shares in BP.
But if you want a car that's most usable day-to-day, will still beat (or keep up with) anything on the road - and I mean ANYTHING, bikes included - then even an almost stock 350 will do the job perfectly well.
That said, no-one buys an Ultima for rational values - so just go with what you're happy with. There's no 'wrong' choice as such, just a matter of speccing something that's fit for purpose.
For the record, I installed a fairly stock engine in the Can-Am and made sure that everything else was top spec. The easiest thing of all to change in an Ultima is the engine. So I could go from 400hp to 720hp just by swapping out the motor and headers!
Of course, I'd also have to shell out about £15k to do it
vipernick said:
How do you decide what engine from American Speed to choose?
There appears to be a large choice!
I am looking for a unit with extreme horse power 600+
Has anyone any apinion on what is best 600/640/720 etc
Also has anyone had any troubles with the units they have bought.
I am in the process of modifying my Ultima which was bought with a 385bhp chevy.
The only decision I have made it will be naturally aspirated!
OK I guess I am Mr 377 I know more about these than most....
Stig is right a 377 640+bhp uses a 18 degree Chapman racing head and that requires a "extreme" exhaust system.
The difference between the engines is simple 640 bhp is basic steel crank and rods, solid lifter dry sump
685bhp is Titanium valves and remapped
720 bhp requires the head to be extensive head porting IIRC this option I shy'd away from for reliablity
Thanks guy's for all your comments. Has anyone considered installing a Ford lump? At the kit car show Rouch Performance have some serious horse power, also have a UK base and their engines have 2year / 24K mile warranty! Web site www.roushperf.com.
Whats so special about the 18 degree exhaust manifold for American speed engine! £4K someones having a laugh!!!!
According to Rouch, the maximum you should be charged for a bespoke manifold should be in the region of £1K each!
Whats so special about the 18 degree exhaust manifold for American speed engine! £4K someones having a laugh!!!!
According to Rouch, the maximum you should be charged for a bespoke manifold should be in the region of £1K each!
Why are equal length headers such a big deal? Chevys don't have flat plane cranks and the exhaust pulses are definitely not equally spaced which is the entire point behind requiring equal length headers. Even if you have an X-pipe the exhaust pulses will still not be balanced truely because of the distance between the X-pipe and the collectors in each bank. I suspect that David Vizards assertion that you actually want fairly unequal length headers so you get a spread of resonant responses throughout the power band is probably correct.
Not that I don't think they're well made but £4k for a set of headers is an outstanding bit of marketing...!
Not that I don't think they're well made but £4k for a set of headers is an outstanding bit of marketing...!
davefiddes said:
Why are equal length headers such a big deal? Chevys don't have flat plane cranks and the exhaust pulses are definitely not equally spaced which is the entire point behind requiring equal length headers. Even if you have an X-pipe the exhaust pulses will still not be balanced truely because of the distance between the X-pipe and the collectors in each bank. I suspect that David Vizards assertion that you actually want fairly unequal length headers so you get a spread of resonant responses throughout the power band is probably correct.
Not that I don't think they're well made but £4k for a set of headers is an outstanding bit of marketing...!
Dave
When I spec'd my exhaust I read Vizards thoughts and ignored them, so the car was built with equal length exhausts and Ultima's jumped in performance term to World record breakers, now I know it's not just the exhaust, it's the package.
The exhaust was designed for more throughput and is repackable and is a jump above the std exhaust
So who's right and who's wrong ....
The exhaust you have fitted definitely looks like a big improvement over the stock Ultima item and I'm sure it is a significant contributor to the speed of your car. On reflection I suspect that getting an unequal length set of headers to have the required performance would require quite a lot of research, experimentation and more research. Money perhaps better spent elsewhere...
My point on the £4K headers! I might accept the first set might be a bit expensive if a lot of time and effort created it, however the next copies would get generated from jigs and fixtures from a pattern or batched built, therefore the costs for these should be a lot lower! £4000 buys a number of hours for a skilled welder/fabricator.
I was told by the factory that they make 50-70 Ultimas built per year.
As you can see from the forum, everyone wants something different. If you are going to make accessories from Ultimas you'd have to expect costs to be recovered over a very limited run, and/or be prepared to make custom EVERYTHING.
As you can see from the forum, everyone wants something different. If you are going to make accessories from Ultimas you'd have to expect costs to be recovered over a very limited run, and/or be prepared to make custom EVERYTHING.
I posted a message regarding engine choice a few months ago - and its cool to see it triggers same interest again. News since last posting is that the CanAm chassis was safely jacked up in the garage last week, and the first 250 rivet holes has been drilled in the aluminum sheets. It's great!
The engine choice also becomes more and more pressing - allthough its the luxury kind of stress. Saw the Audi and BMW's mentioned, and they're probably the most up-dated engines, but are still low rev'ed. My latest idea is to get the block from AS, and I have talked with Kinsler about supplying the rest. Kinsler has full range of all the electronics I need, and can help source and configure the rest of the engine. I think I have decided to sacrifice the supercharger or turbo, for precision in the fuelsystem and upgraded parts for revs around 7.200 rpm. And even though its not nice to think about, I also have to consider things like Belgian emmissions regulation............
Apparently, there is this area around 7.200 rpm which you can reach with a reasonable investment, before it becomes really exotic with titanium upgrades. Anyone who can confirm this?
Leaves the assembly of the engine though.......and I really want to avoid troubles.
The engine choice also becomes more and more pressing - allthough its the luxury kind of stress. Saw the Audi and BMW's mentioned, and they're probably the most up-dated engines, but are still low rev'ed. My latest idea is to get the block from AS, and I have talked with Kinsler about supplying the rest. Kinsler has full range of all the electronics I need, and can help source and configure the rest of the engine. I think I have decided to sacrifice the supercharger or turbo, for precision in the fuelsystem and upgraded parts for revs around 7.200 rpm. And even though its not nice to think about, I also have to consider things like Belgian emmissions regulation............
Apparently, there is this area around 7.200 rpm which you can reach with a reasonable investment, before it becomes really exotic with titanium upgrades. Anyone who can confirm this?
Leaves the assembly of the engine though.......and I really want to avoid troubles.
cupra said:
The engine choice also becomes more and more pressing - allthough its the luxury kind of stress. Saw the Audi and BMW's mentioned, and they're probably the most up-dated engines, but are still low rev'ed. My latest idea is to get the block from AS, and I have talked with Kinsler about supplying the rest. Kinsler has full range of all the electronics I need, and can help source and configure the rest of the engine. I think I have decided to sacrifice the supercharger or turbo, for precision in the fuelsystem and upgraded parts for revs around 7.200 rpm. And even though its not nice to think about, I also have to consider things like Belgian emmissions regulation............
Apparently, there is this area around 7.200 rpm which you can reach with a reasonable investment, before it becomes really exotic with titanium upgrades. Anyone who can confirm this?
Leaves the assembly of the engine though.......and I really want to avoid troubles.
BMW low revs?? this one goed "savely" to 7.800rpm and 500hp, they also do a 580hp...
read this...
BMW V8 Motor 5000 cm²
Max. Leistung: KW (PS) 367 (500) bei 7800 u/min
Max. Drehmoment: 750 NM 3800 u/min
Gemischaufbereitung: vollelektronisch
Zündsystem: elektronisch
Abgasreinigung: Katalysator
Auspuffanlage: Stainless Steel
www.mlr-racetec.com/gtr500.html
GTRene
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