The comp ratio is correct as far as i know Mark. the other stuff is a bit to technical for me
Would still like to hear views on the induction side though i.e. is the ACT stuff overpriced? looks only? Suppose the JE cross-over is the dogs. Looking at the JE engineering site (Re; there alloy Twin Throttle Plenum Chamber) the following info is maybe aimed at the ACT CF stuff? Quote: Using a single one piece casting for the plenum means the throttles are stable and remain well adjusted, alternative designs using carbon fibre for the plenum or 'bolt-on' throttle bodies are less stable. (Customer to supply lower manifold.)
Like I say I am using the ACT CF plenum chamber and I make good power and torque and power delivery is very good. Curves look good and I can drive around at 25mph in 5th through town no problem. The customer supplied lower manifold is only required for Westfields and the like so that adequate under bonnet clearance is provided.
leylandracer wrote:The comp ratio is correct as far as i know Mark. the other stuff is a bit to technical for me
Would still like to hear views on the induction side though i.e. is the ACT stuff overpriced? looks only? Suppose the JE cross-over is the dogs. Looking at the JE engineering site (Re; there alloy Twin Throttle Plenum Chamber) the following info is maybe aimed at the ACT CF stuff? Quote: Using a single one piece casting for the plenum means the throttles are stable and remain well adjusted, alternative designs using carbon fibre for the plenum or 'bolt-on' throttle bodies are less stable. (Customer to supply lower manifold.)
Hi
If you are running a 5 litre engine with standard rover heads and a 295 Degree cam you are running a very low CR at 9:1 ish, I cant find a corrosponding data sheet to 295 degrees but from the rest of thair cams they all run an LSA of around 108 to 110 degrees, quite honestly I think it is not a good combination at all . With the ported rover heads and 5 litre capacity you are going to struggle to get the Volumetric efficiency up to around 75% they also seem to bias to the exhaust timming and to be honest if you can't get the Air and fuel in you don't need to favour the exhaust timing at all. I would think with that cam and CR you are going to have a very "soft" "Fluffy" throttle just off idle and through the mid range and it will be running out of breathing before it really gets going, you have a cam designed to use pulse scavenging but no pulses because of the low CR and restrictive heads.
I would find a cam with a more symetrical inlet/exhaust cam, if you want to retain the fairly agressive cam timing then up the CR to about 11 to 11.5 maybe even 12:1 but get it ground on at least 110 degree LSA.
Alternativly get a better set of heads (merlins) drop the cam timing 10 degrees slightly less LSA, say 110 degrees and have the CR around 10.5 to 11 to 1 you will end up with a much more drivable engine either way, though you will need an aftermarket ECU to get the best out of the engine.
Best regards
Mike
Yes it does start to get a bit technical when you run modified engines.
Firstly can't find the cam in the Kent Cams data sheets do you know what model no. it is?
Re static and dynamic compression ratios, the static is a calculation of how much air/fuel mixture is theoretically squeezed into the combustion space as a ratio of the swept volume of a cylinder and the remaining free space.
The dynamic is a more accurate measurement of cylinder pressure as it takes into account the valve closing positions, with a cam with a lot of duration the inlet valve does not close until the piston is already on the compression stroke therefore reducing the amount of mixture that is compressed, which is bad at low rpm but good for making power at high RPM.
With the 295 duration you suggest your engine may have as little as 6.8/1 comp ratio. which may explain why it does not feel very powerful.
See this article for a 5.7L engine
Why it matters: A 355 engine with a 9:1 static CR using a 252 cam (110 LSA, 106 ICL) has an intake closing point of 52º ABDC and produces a running CR (DCR) of 7.93. The same 9:1 355 engine with a 292 cam (having an intake closing point of 72º ABDC) has a DCR of 6.87, over a full ratio lower. It appears that most gas engines make the best power with a DCR between 7.5 and 8.5 on 91 or better octane. The larger cam's DCR falls outside this range. It would have markedly less torque at lower RPM primarily due to low cylinder pressures, and a substantial amount of reversion back into the intake track. Higher RPM power would be down also since the engine would not be able to fully utilize the extra A/F mixture provided by the ramming effect of the late intake closing. To bring the 292 cam's DCR up to the 7.5 to 8.5:1 desirable for a street engine, the static CR needs to be raised to around 10:1 to 11.25:1. Race engines, using high octane race gas, can tolerate higher DCR's with 8.8:1 to 9:1 a good DCR to shoot for. The static CR needed to reach 9:1 DCR, for the 292 cam mentioned above, is around 12:1.
This lowering of the compression ratio, due to the late closing of the intake valve, is the primary reason cam manufactures specify a higher static compression ratio for their larger cams: to get the running or dynamic CR into the proper range.
Not withstanding the above the first thing to do is get the Megasquirt ECU installed and have it rolling toad tuned to optimize performance, I would not recommend any other changes until more detail re the cam and comp ratio of the engine are known.
The spec of the heads you have suggests that the engine should be capable of producing a peak output of up to or in excees of 320 BHP subject of course to optimizing the fuelling and camshaft for your required usage.
What do you use the car for. all road use. some track?
The cam supposedly wasn’t sold directly by Kent? Quote there reply below:
The NCK 151 had.....
295 degrees duration
Cam lift = 6.98mm
Hydraulic profile
Sorry I'm unable to get installation advice , as it wasn't a cam we sold directly.
Regards
Un-quote
The Marcos will be used 90 percent fast road with the odd track day and drag strip.
Ill more then likely stick with your advice and go with the Megasquirt ECU and see how it goes, I was just thinking along the lines that the ACT induction would guarantee some extra performance with the Megasquirt?
daxtojeiro wrote:Hi,
the shunting has been put down to lots of issues, but basically the way around it is ignition and fuel control. The only way to achieve that is with an aftermarket ECU.
The Plug-n-Play Rover V8 ECUs are out, selling really well, V8D are marketing them, Im just building them www.v8developments.co.uk
cheers,
Phil
Just to follow on with the original topic, Ive decided to go for a full V8D rebuild to 5.3 and use the JE X over with the Jenvy TB's.
The worrying question Will the MegaSquirt be upto the job? I only ask because another engine builder said (Quote)I am also not sure that your Megasquirt system will be good enough!(Un-quote) So just want to be 100% sure and try not to get it wrong
The Megasquirt hasnt been bought yet, so theres still options if somthing else will do better?
Thanks
Steve
daxtojeiro wrote:Hi,
the shunting has been put down to lots of issues, but basically the way around it is ignition and fuel control. The only way to achieve that is with an aftermarket ECU.
The Plug-n-Play Rover V8 ECUs are out, selling really well, V8D are marketing them, Im just building them www.v8developments.co.uk
cheers,
Phil
Just to follow on with the original topic, Ive decided to go for a full V8D rebuild to 5.3 and use the JE X over with the Jenvy TB's.
The worrying question Will the MegaSquirt be upto the job? I only ask because another engine builder said (Quote)I am also not sure that your Megasquirt system will be good enough!(Un-quote) So just want to be 100% sure and try not to get it wrong
The Megasquirt hasnt been bought yet, so theres still options if somthing else will do better?
Thanks
Steve
Ive just got my 5.4 from V8D, still tuning it at the moment on MS3 (full seq fuel and spark)
I have no idea why anyone would think MS isn't up to running that engine, I'd ask V8D, or anyone who has used an MS, if it's up to it, I'm a little biased
Phil
So you cant see any problems with the JE X over set-up i.e. with the Jenvys etc (i think thats what he was getting at Phil)
V8D have said it will have a base map only (Ime presuming they will run the newly built engine on there dyno with the Megasquirt i would be buying) Any recomendations who to take it to for a full map again taking into account the induction set-up? i was thinking of Noble motorsport? i think they are ok with the RV8 and Megasquirt?, Another option is a RTOC (Renault) club member who has done a lot of setting up/mapping for us with the Adaptronic ECU's (Which he supplies) to the various Renault/Toyota Turbos that live around here He hasnt mapped a RV8 or done any tuning with the Megasquirt so maybe that wouldnt be a No1 idea.
daxtojeiro wrote:Hi,
the shunting has been put down to lots of issues, but basically the way around it is ignition and fuel control. The only way to achieve that is with an aftermarket ECU.
The Plug-n-Play Rover V8 ECUs are out, selling really well, V8D are marketing them, Im just building them www.v8developments.co.uk
cheers,
Phil
Just to follow on with the original topic, Ive decided to go for a full V8D rebuild to 5.3 and use the JE X over with the Jenvy TB's.
The worrying question Will the MegaSquirt be upto the job? I only ask because another engine builder said (Quote)I am also not sure that your Megasquirt system will be good enough!(Un-quote) So just want to be 100% sure and try not to get it wrong
The Megasquirt hasnt been bought yet, so theres still options if somthing else will do better?
Thanks
Steve
Ive just got my 5.4 from V8D, still tuning it at the moment on MS3 (full seq fuel and spark)
I have no idea why anyone would think MS isn't up to running that engine, I'd ask V8D, or anyone who has used an MS, if it's up to it, I'm a little biased
Phil
Are you running ITB´s or plenum? With the plenum it will work, but i still wonder how it will work with ITB.. "Resolution" with MS3 maps are still quite small 16x16.. And ITB´s are hard to tune first 10 bars i say. This is my experience.
I would say 80% of my customers use ITBs (Alpha_N), and I've never heard of their not being enough tuning areas. You can make the MS2 or MS3 16x31 if you wanted to, but so far no one has needed to do that. But the option is there.
Indeed, Im even willing to prove this point by offering you a full money back garantee on the ECU if your not happy with its tuning capability.
Out of interest, why don't you ask V8D to tune it and sort an ECU for you as they are supplying the engine.
Also, how much is the Xover set complete with ITBs? Im interested in replacing my inlet next, unless I go for a blower,
Phil
daxtojeiro wrote:I would say 80% of my customers use ITBs (Alpha_N), and I've never heard of their not being enough tuning areas. You can make the MS2 or MS3 16x31 if you wanted to, but so far no one has needed to do that. But the option is there.
Indeed, Im even willing to prove this point by offering you a full money back garantee on the ECU if your not happy with its tuning capability.
Out of interest, why don't you ask V8D to tune it and sort an ECU for you as they are supplying the engine.
Also, how much is the Xover set complete with ITBs? Im interested in replacing my inlet next, unless I go for a blower,
Phil
I'm convinced Phil V8D are going to tune the new engine but Rob did mention that there dyno will strugle with the BHP so it wont be a 100% map?
The JE Xover is expensive but i suppose you are getting a lot of kit for your £2770 + vat which includes: ported and ready to fit with 48mm throttle bodies, fuel rails, aeroquip braided fuel lines, trumpet plates, air boxes, injectors and complete throttle linkage, Hope its worth the expence......
daxtojeiro wrote:I would say 80% of my customers use ITBs (Alpha_N), and I've never heard of their not being enough tuning areas. You can make the MS2 or MS3 16x31 if you wanted to, but so far no one has needed to do that. But the option is there.
Indeed, Im even willing to prove this point by offering you a full money back garantee on the ECU if your not happy with its tuning capability.
Out of interest, why don't you ask V8D to tune it and sort an ECU for you as they are supplying the engine.
Also, how much is the Xover set complete with ITBs? Im interested in replacing my inlet next, unless I go for a blower,
Phil
I'm convinced Phil V8D are going to tune the new engine but Rob did mention that there dyno will strugle with the BHP so it wont be a 100% map?
The JE Xover is expensive but i suppose you are getting a lot of kit for your £2770 + vat which includes: ported and ready to fit with 48mm throttle bodies, fuel rails, aeroquip braided fuel lines, trumpet plates, air boxes, injectors and complete throttle linkage, Hope its worth the expence......
that is a lot of money! No doubt its worth it. We tuned mine on the dyno, but it slipped at 350ft/lbs which was around 3000rpm. But it is a very good starting point. They can then tune it on the road (once fitted), although if you need it tuned on a rolling road, then I always recommend Bailey Performance
BAILEY PERFORMANCE LTD
31 High Street,
Broseley,
Telford,
Shropshire.
TF12 5EZ.
i.e. is the ACT stuff overpriced? looks only? Suppose the JE cross-over is the dogs. Looking at the JE engineering site (Re; there alloy Twin Throttle Plenum Chamber) the following info is maybe aimed at the ACT CF stuff? Quote: Using a single one piece casting for the plenum means the throttles are stable and remain well adjusted, alternative designs using carbon fibre for the plenum or 'bolt-on' throttle bodies are less stable. (Customer to supply lower manifold.) 
but i suppose you are getting a lot of kit for your £2770 + vat which includes: ported and ready to fit with 48mm throttle bodies, fuel rails, aeroquip braided fuel lines, trumpet plates, air boxes, injectors and complete throttle linkage, Hope its worth the expence......
