4 Valves per cylinder ?
Discussion
wadsapple said:
As i understand it the power figures are always a little hard to predict.
They`ve run a dyno program on the 4.7 AJP engine with race cams ported heads ect it made maximum power of
of 426 bhp @ 7000 rpm and 372 ft lbs of torque @ 5000 rpm this is with tube headers and full exhaust system, this is the same program as used with the 4 valve heads .Just as a comparison they ran the same program as a 4.5 with just high lift cams 4 v heads and tube headers and full exaust system the power figures were 480 @ 7500 rpm and 391 ft lbs torque @ 5000 rpm .
intresting as we know the actual dyno figures for a 4.7 in that spec are close to 500hp/445ftlb, if the same difference applies to the 4v 4.5 in real terms them that will be a stonking engine at 550/458! They`ve run a dyno program on the 4.7 AJP engine with race cams ported heads ect it made maximum power of
of 426 bhp @ 7000 rpm and 372 ft lbs of torque @ 5000 rpm this is with tube headers and full exhaust system, this is the same program as used with the 4 valve heads .Just as a comparison they ran the same program as a 4.5 with just high lift cams 4 v heads and tube headers and full exaust system the power figures were 480 @ 7500 rpm and 391 ft lbs torque @ 5000 rpm .
That power increase does seem somewhat optimistic. Let's just get it on the SRR rollers and compare to a standard 4.5 in due course. I would be suprised if a 32 valve head on a 4.5 would out perform a 4.7. But clearly adding this to a 4.7 would be interesting. But I dearly want to see this on the road and proven. Hurry up.
Gazzab said:
That power increase does seem somewhat optimistic. Let's just get it on the SRR rollers and compare to a standard 4.5 in due course. I would be suprised if a 32 valve head on a 4.5 would out perform a 4.7. But clearly adding this to a 4.7 would be interesting. But I dearly want to see this on the road and proven. Hurry up.
Don't forget that the largest gain is likely to be derived from using the variable valve timing. This will permit not only a racier cam but better torque through the range. That's why I reckon if it works it will give definite gains.Will be good to see how it progresses. I suspect it is hard to commercialise as there is such a small number of AJP engines out there to be modded.
Gazzab said:
Oh ok - if that's the case then maybe the increases arent so optimistic. Combined with a 4.7 build then we've got 600bhp...
800 easily and from tickover 
Seriously, I don't know what numbers a 4.7 produces but adding vvt could deliver 10-15% gains if all else is built well. Guessing that a 4.7 in road useable spec delivers 450 then getting towards 500 would be feasible?
Gazzab said:
4.7 offers c490 (ask Mike Saunders). If variable plus multi valve gives 20% then we are close to 600.
I suspect his engine is running tippy race cams? This would make it a pig on the road and off the cams?Adding VVT would allow such an engine to be much more useable at low rpm rather than give more peak power.
Transversely, a road engine compromised for smooth running over the full range would see power increase because you could run a racier cam to extract more power at the top while retaining usability low down.
This assumes the heads themselves do a similar job though.
Maybe these ford heads are a substantial improvement on the AJP?
One would think that a head built for a mass produced conventional engine might not have the legs on one designed from the outset for pure performance but I've no idea. But there's going to be a decade of development between them and a superior tolerance etc so maybe the head is a substantial improvement?
600 just feels optimistic. Is the AJP head that bad?
Edited by DonkeyApple on Sunday 21st October 22:16
4 valve verses 2v heads, the valve curtain area on the 4 valve head with 2 x 37mm valves @ .500 thou lift the area is 4.57 inches, on tha AJP with 45mm valve to get the same curtain area you would have to lift the valve .821 thou off the seat, this would be pointless as you would lose your gas speed in the runner plus the valve would hit the piston due to exceleration, thats why the 4 Valve head will make more power also the port area is bigger on the tumble port heads, porting the AJP head you can only make the runner as big as the valve seat if there is enough material in the runners.
lifting the AJP valve .600 thou as per race cams the curtain area is only 3.34 inches .
lifting the AJP valve .600 thou as per race cams the curtain area is only 3.34 inches .
What is it about the AJP bottom end that allows for so much more power than the standard Ford one?
It's a genuinely interesting project to follow. The modding world in the US haven't come up with too much for this engine in contrast to the LS range and Ford themselves seem to think that the engine in stock form is putting out at its limit for reliability at 400bhp and advise against modding inc FI.
I guess Ford, being broke through the development period, have built it to a price. For example they dropped the direct injection didn't they?
It's a genuinely interesting project to follow. The modding world in the US haven't come up with too much for this engine in contrast to the LS range and Ford themselves seem to think that the engine in stock form is putting out at its limit for reliability at 400bhp and advise against modding inc FI.
I guess Ford, being broke through the development period, have built it to a price. For example they dropped the direct injection didn't they?
Walford said:
Quite how big the market for this kind of conversion could be is had to tell
Obviously standard cars fetch the top money, mods like Nitrons and bigger disc,s are
seen as making the cars even better
fitting an LS is a bit of an unknown, but people like me who have fitted them to cat D cars
themselves could probably get most of there £18k back if they needed to sell simply because
1 not many ever come on the market
2 its a much faster car
3 cheaper to run
4 its reliable
5 you can rebuild the engine yourself,
6 all the tech info is out there in the public domain
but a half TVR half old ford engine would not appeal to the bog standard boys or the engine swap punter
I bet it comes down to how it's marketed. Obviously standard cars fetch the top money, mods like Nitrons and bigger disc,s are
seen as making the cars even better
fitting an LS is a bit of an unknown, but people like me who have fitted them to cat D cars
themselves could probably get most of there £18k back if they needed to sell simply because
1 not many ever come on the market
2 its a much faster car
3 cheaper to run
4 its reliable
5 you can rebuild the engine yourself,
6 all the tech info is out there in the public domain
but a half TVR half old ford engine would not appeal to the bog standard boys or the engine swap punter
If it is branded as a fancy form of AJP and works then I can see it being a mod which adds value.
Something you said about the LS, those who can do all the work themselves are likely to want to do the mod themselves don't you think?
But you can see that where an LS conversion is 'branded' then if kudos grows for that brand then it can command a premium over standard.
Something that has not really been discussed on the Tiv forums is that many of us agree, based on history, that originality will eventually the real premium but I wonder if this isn't part of a generation which is dying out. The younger generation is much more interested in paying a premium for a branded upgraded classic. Such as Singer's 911 etc?
DonkeyApple said:
What is it about the AJP bottom end that allows for so much more power than the standard Ford one?
It's a genuinely interesting project to follow. The modding world in the US haven't come up with too much for this engine in contrast to the LS range and Ford themselves seem to think that the engine in stock form is putting out at its limit for reliability at 400bhp and advise against modding inc FI.
But Ford themselves do a number of models with much more power... Including FI. The engine is also well used on the drag scene, over here, and a good few bits are available. The standard/ base spec Coyote may have a cheaper bottom end, meaning it is built to a price but there are even guys on PH building these engines to mamoth power (look for the guy with the TT Mustang in Readers Cars). It's a genuinely interesting project to follow. The modding world in the US haven't come up with too much for this engine in contrast to the LS range and Ford themselves seem to think that the engine in stock form is putting out at its limit for reliability at 400bhp and advise against modding inc FI.
DonkeyApple said:
I guess Ford, being broke through the development period, have built it to a price. For example they dropped the direct injection didn't they?
They definitely did either drop DI or they are saving it for a later date. If you look at the combustion chambers, there is a very deliberate casting 'flat' surface between the inlet valves, which is likely to mean DI will happen, at some point.Walford said:
Quite how big the market for this kind of conversion could be is had to tell
Obviously standard cars fetch the top money, mods like Nitrons and bigger disc,s are
seen as making the cars even better
fitting an LS is a bit of an unknown, but people like me who have fitted them to cat D cars
themselves could probably get most of there £18k back if they needed to sell simply because
1 not many ever come on the market
2 its a much faster car
3 cheaper to run
4 its reliable
5 you can rebuild the engine yourself,
6 all the tech info is out there in the public domain
but a half TVR half old ford engine would not appeal to the bog standard boys or the engine swap punter
There are some dogs dinner LS conversions out there. Obviously standard cars fetch the top money, mods like Nitrons and bigger disc,s are
seen as making the cars even better
fitting an LS is a bit of an unknown, but people like me who have fitted them to cat D cars
themselves could probably get most of there £18k back if they needed to sell simply because
1 not many ever come on the market
2 its a much faster car
3 cheaper to run
4 its reliable
5 you can rebuild the engine yourself,
6 all the tech info is out there in the public domain
but a half TVR half old ford engine would not appeal to the bog standard boys or the engine swap punter
I can't wait to see what this project delivers, always interesting to see another take on getting more power out of the ajp. I came across the below web page and whilst I know the original heads were proably better designed and made of alloy not iron ( than the iron ones mentioned), its interesting to see some comparison figures when an 8v head is swapped out for a 16v head with no othe mods.
http://www.araoengineering.com
http://www.araoengineering.com
greenracing said:
I can't wait to see what this project delivers, always interesting to see another take on getting more power out of the ajp. I came across the below web page and whilst I know the original heads were proably better designed and made of alloy not iron ( than the iron ones mentioned), its interesting to see some comparison figures when an 8v head is swapped out for a 16v head with no othe mods.
http://www.araoengineering.com
Where are the back to back graphs? I can't find them on that site. I'd like to see the "no other mods" also as fuelling and spark WILL change. So unless the curves on the 8V heads were fully optimised (probably not) then the back to backs aren't really back to backs.... http://www.araoengineering.com
probably a better example to look at, has graphs and a fuller write up
http://www.hotrod.com/techarticles/engine/hrdp_981...
http://www.hotrod.com/techarticles/engine/hrdp_981...
Steve_T said:
Thanks, very interesting. That guy certainly knows his onions. I remember reading his articles in Fast Car 25 years ago (blimey).IMO the AJP is already quite a 'cammy' engine (max torque @ >5krpm, max power @ >7krpm), I'm not sure that regular 4v heads would do it many favours in the drivability stakes. Although a 4.7 with Vizard heads would be an interesting proposition
Steve_T said:
The problem with these articles is that they are actually advertorials for their product so 'information' is at huge risk of being skewed. Was an interesting read though but context is important.Gassing Station | Cerbera | Top of Page | What's New | My Stuff