Sc-Power Supercharger kit
Discussion
I see your problem.
The cost issue comes down to how much of the work you can do yourself.
Two good friends of mine installed superchargers themselves in their own garages.Not professional mechanics, just competent with a tool kit.
I don't know what engine management system either of them already had.
Both were on larger engines than yours (one 4.5, one 5.0 I think), both went for lots of power, both within a couple of months had to have the engine rebuilt with stronger internals.
As you are starting with a 4 litre, you won't be going over 400 bhp I imagine - that level seems to be the point at which the risk of breaking the standard engine begins.
So, if you can find a supercharger kit for reasonable money and install it yourself, you could then go for Megasquirt engine management sysgtem, which again you can install yourself, after which the issue is getting it mapped to suit. There is lots of online help, and as Megasquirt is used in all sorts of cars, and as the rally scene is big in your part of Europe, there is a reasonable chance that you can find a tuning shop in Hungary with a rolling road that can help you.
I would find the tuning shop first, and get as much advice as you can from them, and then buy what they suggest.
Don't go mad chasing power - you won't be able to use over 400 bhp in any meaningful way, indeed it's debatable whether you can even use over 350 bhp on public roads, so keep your plans reasonable and you shouldn't (no promises) break the engine.
The cost issue comes down to how much of the work you can do yourself.
Two good friends of mine installed superchargers themselves in their own garages.Not professional mechanics, just competent with a tool kit.
I don't know what engine management system either of them already had.
Both were on larger engines than yours (one 4.5, one 5.0 I think), both went for lots of power, both within a couple of months had to have the engine rebuilt with stronger internals.
As you are starting with a 4 litre, you won't be going over 400 bhp I imagine - that level seems to be the point at which the risk of breaking the standard engine begins.
So, if you can find a supercharger kit for reasonable money and install it yourself, you could then go for Megasquirt engine management sysgtem, which again you can install yourself, after which the issue is getting it mapped to suit. There is lots of online help, and as Megasquirt is used in all sorts of cars, and as the rally scene is big in your part of Europe, there is a reasonable chance that you can find a tuning shop in Hungary with a rolling road that can help you.
I would find the tuning shop first, and get as much advice as you can from them, and then buy what they suggest.
Don't go mad chasing power - you won't be able to use over 400 bhp in any meaningful way, indeed it's debatable whether you can even use over 350 bhp on public roads, so keep your plans reasonable and you shouldn't (no promises) break the engine.
Just about every engine on the planet can handle 5 psi of boost. A fresh set of shells and a mild cam would have it tearing up the tarmac. Stock valvetrain and lifters can be retained. Keeping to stock rpm's limits mechanical stresses so basically you have an unstressed engine that's fitted with bolt on parts.
One of the issues with FI is that people usually want more and more .. there is no reason why a light pressure install shouldn't run for ever with no intercooler and the lucas ecu .. I've mapped loads of them now in just such a spec. Ive even got one customer running a 4 litre to 440hp on the lucas. The fuelling isn't pretty but it is at least safe.
Keep it simple and keep it low boost and you will be absolutely fine.
The problem stories are usually when someone has tried to go too far without considering things fully.
Keep it simple and keep it low boost and you will be absolutely fine.
The problem stories are usually when someone has tried to go too far without considering things fully.
Forced induction tech has out performed the mechanical tech they are bolted onto and especially a 1950’s design engine and it’s only in the last 10-15 years engines are being designed to actually take the power rather than melt pistons and twist cranks. I’d like to see the shells of a forced induction RV8 after 10,000 miles let alone 50.
The truth about power is it’s increasingly expensive to gain the stuff but in reality it barely changes the cars overall road going speed and often the power is unusable until the car is neutrally balanced and in a fully straight line which can be 80 yards after an apex and only 50 yards before starting the process of slowing down for the next bend lol ( point and squirt ) car which is very boring.
If going higher Cc is a problem for the o/p A small turbo will be a good idea but you soon realise a boost of 50 hp is not enough or you become addicted to wanting just a little bit more and on a worn engine with very old tech... it’s a one way street to emptying your wallet if your not careful.
I suppose it’s why some engine builders won’t touch these jobs unless it’s a total package 10k or the customer excepts responsibility for what happens and if that’s the case fill your boots but if cost is an issue I’d spend the 4k on making your engine the best it can be after having a health check on its bottom end. You will end up with similar power to a bog standard 450 anyway if done properly and let’s be honest big ported heads are way sexier than a small turbo or charger that’s being restricted to protect the engine.
The truth about power is it’s increasingly expensive to gain the stuff but in reality it barely changes the cars overall road going speed and often the power is unusable until the car is neutrally balanced and in a fully straight line which can be 80 yards after an apex and only 50 yards before starting the process of slowing down for the next bend lol ( point and squirt ) car which is very boring.
If going higher Cc is a problem for the o/p A small turbo will be a good idea but you soon realise a boost of 50 hp is not enough or you become addicted to wanting just a little bit more and on a worn engine with very old tech... it’s a one way street to emptying your wallet if your not careful.
I suppose it’s why some engine builders won’t touch these jobs unless it’s a total package 10k or the customer excepts responsibility for what happens and if that’s the case fill your boots but if cost is an issue I’d spend the 4k on making your engine the best it can be after having a health check on its bottom end. You will end up with similar power to a bog standard 450 anyway if done properly and let’s be honest big ported heads are way sexier than a small turbo or charger that’s being restricted to protect the engine.
Edited by Classic Chim on Monday 15th February 09:11
Shells would be fine as the metal bits rotate on a wedge of oil as is the norm. Shell wear usually occurs during ignition start up when the wedge hasn't formed. Modern oils and shell technology hasn't remained in the dark ages despite this being an elderly block. Whenever I've opened up a turbo engine the stock bottom end looks, well completely stock. Totally unremarkable.
As an aside my ancient turbo workhorse has clocked almost 220k miles and I'm fairly certain it's never been opened up so it'll have shells that were fitted over 20 years ago. I changed the head gasket a few years back and the cross hatching in the bores was still evident. I blame modern oils for being so good.:-)
As an aside my ancient turbo workhorse has clocked almost 220k miles and I'm fairly certain it's never been opened up so it'll have shells that were fitted over 20 years ago. I changed the head gasket a few years back and the cross hatching in the bores was still evident. I blame modern oils for being so good.:-)
Indeed.
At low revs where any damage might occur (due to lower hydrodynamic wedge pressure ) the turbo or centrifugal sc isn't on boost anyway. Large positive displacement sc can give a lot of boost low down, but again you would spec the compression appropriately / set the ignition point accordingly.
Your ignition timing will mean that the cylinder pressure just after tdc will be not dis-similar to a normally aspirated engine even on boost.
Turbos increase charge density so the time of the pressure is longer, and averagely greater over the power stroke as a whole but the actual peak pressure the piston and bearing is subjected to is not that much greater.
At low revs where any damage might occur (due to lower hydrodynamic wedge pressure ) the turbo or centrifugal sc isn't on boost anyway. Large positive displacement sc can give a lot of boost low down, but again you would spec the compression appropriately / set the ignition point accordingly.
Your ignition timing will mean that the cylinder pressure just after tdc will be not dis-similar to a normally aspirated engine even on boost.
Turbos increase charge density so the time of the pressure is longer, and averagely greater over the power stroke as a whole but the actual peak pressure the piston and bearing is subjected to is not that much greater.
But the time it takes for the engine to spin up is greatly reduced when accelerating with extra power.
How does that effect the big end shells and the oils ability to maintain its film between the two metals or does it have little effect.
Going from 2000 revs to 6000 in second gear is likely to be a very short period of time on full chat with FI
Just wondering really.
How does that effect the big end shells and the oils ability to maintain its film between the two metals or does it have little effect.
Going from 2000 revs to 6000 in second gear is likely to be a very short period of time on full chat with FI
Just wondering really.
OP- if you need to keep the engine at 4.0 capacity for legal reasons but want a stack more performance, could you not sell the Chim and replace it with a later Speed-6 engined TVR?! 
In all seriousness after getting my 4.0 Chimaera a few years ago I quickly found myself in a similar situation, looking at the various ways to extract more performance without fundamentally replacing the engine. Eventually I reached the conclusion that it would necessitate a huge amount of money spent, for very little gain- particularly as I was keen to keep to the N/A route.
As it turned out, my car ended up having an engine rebuild after a strip down that was only intended as a camshaft change. By this point I'd decided I would get the engine rebuilt to largely original spec (for the reasons above), and post-rebuild the car felt worlds better than before.
I am convinced that there are a lot of Chimaera/Griff owners out there wanting more power from what appear to be healthy engines, that are in fact just in need of a strip down and rebuild. I'm not an expect on the RV8 engine by any stretch of the imagination, but my experience suggests to me that it is an engine that is exceedingly good at hiding wear & tear- mine certainly felt fine aside from feeling like it could benefit from a new cam at 78k miles, yet the reality when it was pulled apart was very different! This has been born out by how it now feels post-rebuild.
The problem with that of course, is that if it the engine is going to be rebuilt then the added cost of upgraded parts is quite small in the overall cost at that point, so it starts making more sense. But then you are quickly into budget-creep territory and quickly added £2-3k onto a £5k rebuild bill- to gain perhaps 30-50hp over a healthy standard car. Sure a 50bhp increase is probably going to be noticeable, but 30bhp? I'm not sure- and even if it is, how long will that feeling of increased power last before it just feels 'normal' again and the itch for even more power returns?
To come full circle back to my original tongue-in-cheek (but also slightly serious) point, we purchased a 4.0 Tuscan last summer to go alongside my now healthy Chimaera. That does feel like a proper step-up, not just in terms of overall performance, but also in the way in which that performance is delivered. It has also not yet had me feeling like it needs any more! So by my very scientific reckoning, I've calculated that my humble 4.0 Chimaera would need another 150ish bhp, a large dollop more torque, and a much lighter flywheel to feel fundamentally faster than it currently is
To get that level of performance from my £12k Chimaera, the total cost would surely be approaching the £23k we paid for our Tuscan (if not more), and that is before even getting into the costs of the other improvements which would then likely be necessary (brakes / suspension / driveshafts etc).
On that basis I can enjoy my Chimaera for what it is- a great sounding open topped British roadster that looks great and goes plenty fast enough.
To achieve outright performance from the 4.0 RV8, the cost is going to be way out of proportion to the performance delivered.
In all seriousness after getting my 4.0 Chimaera a few years ago I quickly found myself in a similar situation, looking at the various ways to extract more performance without fundamentally replacing the engine. Eventually I reached the conclusion that it would necessitate a huge amount of money spent, for very little gain- particularly as I was keen to keep to the N/A route.
As it turned out, my car ended up having an engine rebuild after a strip down that was only intended as a camshaft change. By this point I'd decided I would get the engine rebuilt to largely original spec (for the reasons above), and post-rebuild the car felt worlds better than before.
I am convinced that there are a lot of Chimaera/Griff owners out there wanting more power from what appear to be healthy engines, that are in fact just in need of a strip down and rebuild. I'm not an expect on the RV8 engine by any stretch of the imagination, but my experience suggests to me that it is an engine that is exceedingly good at hiding wear & tear- mine certainly felt fine aside from feeling like it could benefit from a new cam at 78k miles, yet the reality when it was pulled apart was very different! This has been born out by how it now feels post-rebuild.
The problem with that of course, is that if it the engine is going to be rebuilt then the added cost of upgraded parts is quite small in the overall cost at that point, so it starts making more sense. But then you are quickly into budget-creep territory and quickly added £2-3k onto a £5k rebuild bill- to gain perhaps 30-50hp over a healthy standard car. Sure a 50bhp increase is probably going to be noticeable, but 30bhp? I'm not sure- and even if it is, how long will that feeling of increased power last before it just feels 'normal' again and the itch for even more power returns?
To come full circle back to my original tongue-in-cheek (but also slightly serious) point, we purchased a 4.0 Tuscan last summer to go alongside my now healthy Chimaera. That does feel like a proper step-up, not just in terms of overall performance, but also in the way in which that performance is delivered. It has also not yet had me feeling like it needs any more! So by my very scientific reckoning, I've calculated that my humble 4.0 Chimaera would need another 150ish bhp, a large dollop more torque, and a much lighter flywheel to feel fundamentally faster than it currently is
To get that level of performance from my £12k Chimaera, the total cost would surely be approaching the £23k we paid for our Tuscan (if not more), and that is before even getting into the costs of the other improvements which would then likely be necessary (brakes / suspension / driveshafts etc).
On that basis I can enjoy my Chimaera for what it is- a great sounding open topped British roadster that looks great and goes plenty fast enough.
To achieve outright performance from the 4.0 RV8, the cost is going to be way out of proportion to the performance delivered.
It all sounds sensible but....what do you think robbed that much hp from your engine other than the worn cam shaft? Was it low on compression?
It is not the capacity I must retain it is the engine code (first 4? digit of the engine number) what must be the same or maybe another tvr chimera engine - 450 or 500 - can be legilized in my car if there’s proof that the engine was available for this car. In other words it must be a tvr block from the same model generation.
It is not the capacity I must retain it is the engine code (first 4? digit of the engine number) what must be the same or maybe another tvr chimera engine - 450 or 500 - can be legilized in my car if there’s proof that the engine was available for this car. In other words it must be a tvr block from the same model generation.
Edited by Supercharged5 on Monday 15th February 17:05
Classic Chim said:
But the time it takes for the engine to spin up is greatly reduced when accelerating with extra power.
How does that effect the big end shells and the oils ability to maintain its film between the two metals or does it have little effect.
Going from 2000 revs to 6000 in second gear is likely to be a very short period of time on full chat with FI
Just wondering really.
All's fine because everything's rotating. The torque is being produced for longer due to the extra fuel being burnt in the cylinder and as Jules as said, peak torque lasts for only a nano second so it doesn't really effect reliability. Consider a revvy atmo engine at over 6.5k rpm's. Those mechanical stresses will be far more then a turbo engine experiences making more power and torque within lesser rpm's.How does that effect the big end shells and the oils ability to maintain its film between the two metals or does it have little effect.
Going from 2000 revs to 6000 in second gear is likely to be a very short period of time on full chat with FI
Just wondering really.
On the exhaust stroke an atmo rod and piston wants to head into orbit. On a turbocharged engine the pressure above the piston (due the turbine causing an obstruction in the exhaust tract) has a damping effect. Less mechanical stress will be present.
The issues with turbo's are really all about heat management and obviously spark and fuelling need to be addressed.
I've yet to have a supercharged build but expect it to be equally exciting.
Supercharged5 said:
It all sounds sensible but....what do you think robbed that much hp from your engine other than the worn cam shaft? Was it low on compression?
The problem is I don't know what bhp it was making before the rebuild (I don't know what bhp it is now either)- it just felt a bit flat at higher revs so I knew the camshaft needed doing. It didn't feel particularly slow to me. But I did feel like I wanted more power- but that was mainly because I had got used to it. When the engine was stripped it was found to have a couple of snapped piston rings, the valve seals were completely shot, and the main bearings were worn. I also had all new rocker arms etc fitted. My original intention (before I knew it needed rebuilding) had been to go down the aftermarket ECU route after the camshaft change as I liked the idea of improved drivability, reliability, with a bit of a potential performance boost. But post-rebuild the car drives so well it feels like that is un-necessary now, and the arrival of the Tuscan has recalibrated what a proper performance increase feels like in a very similar car- and that level of increase on the Chimaera is just not feasible for the costs involved. I couldn't imagine spending more on my Chimaera than we paid for the Tuscan to end up with a car that still probably wouldn't be as good- but granted if the Chimaera is 'the one' then I can see why people would (and have done so).
Supercharged5 said:
It is not the capacity I must retain it is the engine code (first 4? digit of the engine number) what must be the same or maybe another tvr chimera engine - 450 or 500 - can be legilized in my car if I there’s proof that the engine was available for this car. In other words it must be a tvr block from the same model generation.
Ah that makes sense. I guess the other hurdle is the availability of other cars over there? Otherwise would it not be worth swapping to a 450 or 500 as a better starting point- assuming you haven't already sunk too much into the existing car. That would surely be the cheapest way to gain a big chunk of performance?My car is the only TVR ever registered in the country :-)
It is also not an option sourcing a complete car 450 or 500 as the registration is expensive (~1500£) and there’s customs from 01 january if I import it from the UK. It would also be tricky to sell mine. It’s the only one here but it’s RHD and everyone echoes the same story about how unreliable these cars were.
Regarding performance expectations and getting used to the next level / always wanting more I know this very well... 10 years of mx5 ownership, six cars, mk1/mk2 NA/Turbo/M45SC/Mp62SC from 110 hp to 240hp and the itch for more every time I half finished the current project.
I don’t want to do it on this car. I’ll make a compression/leak down test and if it says that the engine internals ar OK I’ll have the Mc1 cam installed and that’s all. If something is worn in the head I’ll swap it for a stage 3/4 maybe and leave the bottom part of the engine untouched until it developes a problem or shows signs of wear.
If the compression test shows poor numbers caused by piston/ring/cylinder wear I think I will go for a V8D overhauled long block with pocketed pistons and a good head. Their website shows good options but it’s hard to figure out how much would such a long block cost if I can’t give them my engine as exchange item.
It is also not an option sourcing a complete car 450 or 500 as the registration is expensive (~1500£) and there’s customs from 01 january if I import it from the UK. It would also be tricky to sell mine. It’s the only one here but it’s RHD and everyone echoes the same story about how unreliable these cars were.
Regarding performance expectations and getting used to the next level / always wanting more I know this very well... 10 years of mx5 ownership, six cars, mk1/mk2 NA/Turbo/M45SC/Mp62SC from 110 hp to 240hp and the itch for more every time I half finished the current project.
I don’t want to do it on this car. I’ll make a compression/leak down test and if it says that the engine internals ar OK I’ll have the Mc1 cam installed and that’s all. If something is worn in the head I’ll swap it for a stage 3/4 maybe and leave the bottom part of the engine untouched until it developes a problem or shows signs of wear.
If the compression test shows poor numbers caused by piston/ring/cylinder wear I think I will go for a V8D overhauled long block with pocketed pistons and a good head. Their website shows good options but it’s hard to figure out how much would such a long block cost if I can’t give them my engine as exchange item.
Edited by Supercharged5 on Monday 15th February 17:04
Supercharged5 said:
Rod bending is the main risk at low revs with SC as I learnt on my Eaton mp62 supercharged mx5.
short of running the car through a ford what on earth happens to bend a rod ? That is not a result of supercharging per se .. it is the result of some extreme cylinder pressures which should never happen, or loss of oil to crank (seized bearing) “Here’s a list of the most power the stock engine of the MX5 / Miata can take, reliability depends a lot on the health of the engine and how it’s used, launches or high rpm will kill rods and oil pumps quickly, as well as gearboxes. “
https://bofiracing.co.uk/how-to-keep-your-turbo-mx...
Too much torque at 2.5-3k rpm bends the stock rods, that’s the first limitation on a miata block. An aggressive pulley ratio on the bigger Eaton supercharger (mp62) generates 8psi from 2k rpm what is too much for the rods if the ignition is not pulled back at that rev range.
https://bofiracing.co.uk/how-to-keep-your-turbo-mx...
Too much torque at 2.5-3k rpm bends the stock rods, that’s the first limitation on a miata block. An aggressive pulley ratio on the bigger Eaton supercharger (mp62) generates 8psi from 2k rpm what is too much for the rods if the ignition is not pulled back at that rev range.
Exactly so how is that the fault of the supercharger ? If you know the limitations of a system, yet go beyond that, youve got to expect trouble. that's not the supercharger's fault.
This is why things like turbos and nitrous get a bad rep. It's largely the human element that cocks it up.
This is why things like turbos and nitrous get a bad rep. It's largely the human element that cocks it up.
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