FS 16V performance
01-12-2010, 02:37 AM
#61
Nordschleife Master
01-12-2010, 09:32 AM
#62
Drifting
What do you base your statements on ^^ , (like the 32v vs. euro throttle body measurement)
The US 85-86 gets woken up by chips, the 5.0 "screamer motor" in the thread I referenced is putting down 100hp more at the wheels from a different exhaust cam as the only significant physical change and only at 6400 RPM.
NOPE, its got to be the mapping/timing.
Ferrari is getting 500bhp out of 4.3 lt and now is getting 570bhp out of a 4.6 lt engine using rpm's and compression.
There is no reason that I can see, why a 928 4.7 can not get 375-400 rwhp with the a top end like the one for sale in this thread and say lighter, smaller, reshaped pistons with a slightly raised compression revving north of 7000.
I think it comes down to having the right software.
The US 85-86 gets woken up by chips, the 5.0 "screamer motor" in the thread I referenced is putting down 100hp more at the wheels from a different exhaust cam as the only significant physical change and only at 6400 RPM.
NOPE, its got to be the mapping/timing.
Ferrari is getting 500bhp out of 4.3 lt and now is getting 570bhp out of a 4.6 lt engine using rpm's and compression.
There is no reason that I can see, why a 928 4.7 can not get 375-400 rwhp with the a top end like the one for sale in this thread and say lighter, smaller, reshaped pistons with a slightly raised compression revving north of 7000.
I think it comes down to having the right software.
01-12-2010, 01:48 PM
#63
Rennlist Member
No, tuning will not get the 2 valver 4.7s up over 300rwhp.
remember, the screamer motor went from near 300rwhp, as did my very strong 330rwhp 5 liter with only headers and air mox mods[ to 370 rwhp with no tuning at all. with tune, it went up to 385, but it was a very peaky 385rwhp. the only changes were cams, for the most part ( 1mm more lift, and some duration shifts)
Tuning on the 2 valvers, as I found with spark and fuel changes, only optimized from 2-3 hp for spark and near 5hp for fuel. the main reason for tuning is not for peak hp, but for driveability, safety, and to give a broader hp curve.
now, the real question is, do you WANT your 928 engine running over 6500rpm? What you really want is a broad hp curve for your 928, from 4500rpm to 6500rpm, and a real easy way to do this is to get more displacement, regardless of the street cams, and intake. with no other changes, a 210rwhp 4.5 liter went to 250rwhp with euro stuff and 4.7 and then with ONLY a 5 liter upgrade, a nice 290rwhp, all being done with the 1"x2.5" AFM opening. (think restrictor plate racing!
)
QUOTE=tv;7216315]What do you base your statements on ^^ , (like the 32v vs. euro throttle body measurement)
The US 85-86 gets woken up by chips, the 5.0 "screamer motor" in the thread I referenced is putting down 100hp more at the wheels from a different exhaust cam as the only significant physical change and only at 6400 RPM.
NOPE, its got to be the mapping/timing.
Ferrari is getting 500bhp out of 4.3 lt and now is getting 570bhp out of a 4.6 lt engine using rpm's and compression.
There is no reason that I can see, why a 928 4.7 can not get 375-400 rwhp with the a top end like the one for sale in this thread and say lighter, smaller, reshaped pistons with a slightly raised compression revving north of 7000.
I think it comes down to having the right software.[/QUOTE]
remember, the screamer motor went from near 300rwhp, as did my very strong 330rwhp 5 liter with only headers and air mox mods[ to 370 rwhp with no tuning at all. with tune, it went up to 385, but it was a very peaky 385rwhp. the only changes were cams, for the most part ( 1mm more lift, and some duration shifts)
Tuning on the 2 valvers, as I found with spark and fuel changes, only optimized from 2-3 hp for spark and near 5hp for fuel. the main reason for tuning is not for peak hp, but for driveability, safety, and to give a broader hp curve.
now, the real question is, do you WANT your 928 engine running over 6500rpm? What you really want is a broad hp curve for your 928, from 4500rpm to 6500rpm, and a real easy way to do this is to get more displacement, regardless of the street cams, and intake. with no other changes, a 210rwhp 4.5 liter went to 250rwhp with euro stuff and 4.7 and then with ONLY a 5 liter upgrade, a nice 290rwhp, all being done with the 1"x2.5" AFM opening. (think restrictor plate racing!
)QUOTE=tv;7216315]What do you base your statements on ^^ , (like the 32v vs. euro throttle body measurement)
The US 85-86 gets woken up by chips, the 5.0 "screamer motor" in the thread I referenced is putting down 100hp more at the wheels from a different exhaust cam as the only significant physical change and only at 6400 RPM.
NOPE, its got to be the mapping/timing.
Ferrari is getting 500bhp out of 4.3 lt and now is getting 570bhp out of a 4.6 lt engine using rpm's and compression.
There is no reason that I can see, why a 928 4.7 can not get 375-400 rwhp with the a top end like the one for sale in this thread and say lighter, smaller, reshaped pistons with a slightly raised compression revving north of 7000.
I think it comes down to having the right software.[/QUOTE]
01-12-2010, 01:57 PM
#64
Rennlist Member
Yep, and it was pretty cool to see that the 4.7 turned 5 liter euro making 293rwhp. but even cooler to see an unmolested 5 liter 4 valve, make the same, through a stock exhuast (no cat) and everything bone stock. Im sure if you did a conversion of the 5 liter 2valver to MAF, it might be similar, but it is a heck of a lot of work. BUT, the very nice thing about the 2 valver is how simple the top end is. that intake isnt that bad. the heads can be made to flow well, euro cams are good.
That is MORE than one question and way more than one answer..... more displacement makes more power. Using the 85-86 short block REQUIRES notching valve reliefs into the pistons which means taking the engine all apart. After you do the full monty on the 16 valve you MIGHT get 300 hp at the rear wheels with big race cams Euro parts etc. etc. or just about what you get from a good S-4 engine with headers no cat.
and way more than one answer..... more displacement makes more power. Using the 85-86 short block REQUIRES notching valve reliefs into the pistons which means taking the engine all apart. After you do the full monty on the 16 valve you MIGHT get 300 hp at the rear wheels with big race cams Euro parts etc. etc. or just about what you get from a good S-4 engine with headers no cat.
01-12-2010, 02:00 PM
#65
Drifting
All those engines listed for good power figures are all 4v head design with variable cam timing. And one even has direct injection. You can't really compare any of them with the Porsche V8.
01-12-2010, 02:08 PM
#66
Drifting
Correct if I am wrong, but 2V vs. 4V in this discussion is all about flow correct?
Flow of air mainly and the fuel into the chamber. And we know because others have measured it that these 2V heads flow enough air (I could show you threads where that was determined)
So if the head flows enough volume, whats it matter whether it comes in 1 opening or 2.
And the corvette Z06 is still using a 2V design, though larger displacement.
Flow of air mainly and the fuel into the chamber. And we know because others have measured it that these 2V heads flow enough air (I could show you threads where that was determined)
So if the head flows enough volume, whats it matter whether it comes in 1 opening or 2.
And the corvette Z06 is still using a 2V design, though larger displacement.
01-12-2010, 02:23 PM
#67
Drifting
And I thought vario cam was mainly to preserve tourque in the low end (from Hensler) and for efficiency for pollution
from wiki - Valve timing and the valve profile are continuously altered according to conditions and engine load. For improved responsiveness on cold starts, VarioCam Plus raises the amount of lift and retards valve timing. At medium revs with minimal loads, the valve lift is lowered and timing advanced to help minimize fuel consumption and emissions. For maximum power and torque, the lift is raised and the timing is advanced.
If you just want max power that should not be an issue.
from wiki - Valve timing and the valve profile are continuously altered according to conditions and engine load. For improved responsiveness on cold starts, VarioCam Plus raises the amount of lift and retards valve timing. At medium revs with minimal loads, the valve lift is lowered and timing advanced to help minimize fuel consumption and emissions. For maximum power and torque, the lift is raised and the timing is advanced.
If you just want max power that should not be an issue.
01-12-2010, 02:49 PM
#68
Drifting
Variable cams lets you run an aggressive cam timing on the top end, but still have a reasonable idle quality. It also provides a much fatter torque curve in between idle and high speed.
You could get more power out of a 2v engine with these heads, but you would need an aggressive cam and to spin the engine to 8000 rpm. 928 engines don't like to spin much past 6500 due to oiling issues. You can't get a cam with more than ~0.500 lift in the cam carriers. You would also need to replace the intake manifold with something that had much shorter runners and 2-3x the plenum volume.
Basically in the end you could come up with something that makes good power, but not a lot of torque. Either way, these are nice parts. I hope they sell.
You could get more power out of a 2v engine with these heads, but you would need an aggressive cam and to spin the engine to 8000 rpm. 928 engines don't like to spin much past 6500 due to oiling issues. You can't get a cam with more than ~0.500 lift in the cam carriers. You would also need to replace the intake manifold with something that had much shorter runners and 2-3x the plenum volume.
Basically in the end you could come up with something that makes good power, but not a lot of torque. Either way, these are nice parts. I hope they sell.
01-12-2010, 03:31 PM
#69
Rennlist Member
+1. Yep, all apples and oranges . He is trying to compare displacement and judge HP potential. not possible. compression ratios, all sorts of electronics to allow a 12:1 compression engine from not having to use race gas, etc.
the 928 engine is a great blend of street and race technology. very tame, but reliable. you want to turn it into a ferarri engine, better stand back, because its going to blow.
for a note, the BMW 3.2 liter engines commonly used on the racing circuite, make near 380rwhp with very few mods. Individual throttle bodies, big after market intake plennum, Vanos, and high compression. Plus, they twist up to 8500rpm. the run between 6000rpm and 8500rpm. our engines are just not designed for this kind of operation. Thats why we just go bigger displacement. Its the bigger hammer approach, but it works and can use mostly stock stuff on the intake and electronics. in the end, the two cars are pretty equal. the bmw is slightly lighter and has a narrower HP range, the 928 has broader hp and is heavier. 928s shift at 6600rpm and bmws shift at 8400rpm. both put out near the same HP/weight.
Im still waiting to see a 2 valve euro 5 liter make as much as my stock 5 liter with a set of headers and air box mods. (i.e. 335rwhp) (jim, dont call it a fluke, Rons GT with the same set up , made identical power to mine after mine was a little more beat up, as in 320rwhp and the hp curves looked identical for the most part.)
the 928 engine is a great blend of street and race technology. very tame, but reliable. you want to turn it into a ferarri engine, better stand back, because its going to blow.
for a note, the BMW 3.2 liter engines commonly used on the racing circuite, make near 380rwhp with very few mods. Individual throttle bodies, big after market intake plennum, Vanos, and high compression. Plus, they twist up to 8500rpm. the run between 6000rpm and 8500rpm. our engines are just not designed for this kind of operation. Thats why we just go bigger displacement. Its the bigger hammer approach, but it works and can use mostly stock stuff on the intake and electronics. in the end, the two cars are pretty equal. the bmw is slightly lighter and has a narrower HP range, the 928 has broader hp and is heavier. 928s shift at 6600rpm and bmws shift at 8400rpm. both put out near the same HP/weight.
Im still waiting to see a 2 valve euro 5 liter make as much as my stock 5 liter with a set of headers and air box mods. (i.e. 335rwhp) (jim, dont call it a fluke, Rons GT with the same set up , made identical power to mine after mine was a little more beat up, as in 320rwhp and the hp curves looked identical for the most part.)
Variable cams lets you run an aggressive cam timing on the top end, but still have a reasonable idle quality. It also provides a much fatter torque curve in between idle and high speed.
You could get more power out of a 2v engine with these heads, but you would need an aggressive cam and to spin the engine to 8000 rpm. 928 engines don't like to spin much past 6500 due to oiling issues. You can't get a cam with more than ~0.500 lift in the cam carriers. You would also need to replace the intake manifold with something that had much shorter runners and 2-3x the plenum volume.
Basically in the end you could come up with something that makes good power, but not a lot of torque. Either way, these are nice parts. I hope they sell.
You could get more power out of a 2v engine with these heads, but you would need an aggressive cam and to spin the engine to 8000 rpm. 928 engines don't like to spin much past 6500 due to oiling issues. You can't get a cam with more than ~0.500 lift in the cam carriers. You would also need to replace the intake manifold with something that had much shorter runners and 2-3x the plenum volume.
Basically in the end you could come up with something that makes good power, but not a lot of torque. Either way, these are nice parts. I hope they sell.
01-12-2010, 04:21 PM
#70
Drifting
Yes I understand what you guys have said;
here is the plenum study where btw Carl Fuasett mentions 420 N/A hp for a 16V - https://rennlist.com/forums/928-foru...prototype.html
here are the cams - https://rennlist.com/forums/928-foru...elections.html
Together with Greg Gray's work and some others - (lightweight internals, dry sump, crank drilling, .......)
I'll start a thread sometime down the line with all the particulars, but other than the plenum, I do not see where there is a problem. (even if necessary a different engine management system)
here is the plenum study where btw Carl Fuasett mentions 420 N/A hp for a 16V - https://rennlist.com/forums/928-foru...prototype.html
here are the cams - https://rennlist.com/forums/928-foru...elections.html
Together with Greg Gray's work and some others - (lightweight internals, dry sump, crank drilling, .......)
I'll start a thread sometime down the line with all the particulars, but other than the plenum, I do not see where there is a problem. (even if necessary a different engine management system)
01-12-2010, 04:58 PM
#71
Rennlist Member
With carls intake, that is probably as good as its going to get. who knows what that will do, as Carl let us down and made it for a blower! 
still, you are left with relatively low compression 10:1 and fairly small ports and valves, with a mild cam. (dont forget about the rpm limitations) .
best to just get as much displacement as possible, especially since it is so CHEAP!! short blocks are around $1000 and flycutting the pistons for the valves is pretty easy, even by hand.
still, you are left with relatively low compression 10:1 and fairly small ports and valves, with a mild cam. (dont forget about the rpm limitations) .
best to just get as much displacement as possible, especially since it is so CHEAP!! short blocks are around $1000 and flycutting the pistons for the valves is pretty easy, even by hand.
Yes I understand what you guys have said;
here is the plenum study where btw Carl Fuasett mentions 420 N/A hp for a 16V - https://rennlist.com/forums/928-foru...prototype.html
here are the cams - https://rennlist.com/forums/928-foru...elections.html
Together with Greg Gray's work and some others - (lightweight internals, dry sump, crank drilling, .......)
I'll start a thread sometime down the line with all the particulars, but other than the plenum, I do not see where there is a problem. (even if necessary a different engine management system)
here is the plenum study where btw Carl Fuasett mentions 420 N/A hp for a 16V - https://rennlist.com/forums/928-foru...prototype.html
here are the cams - https://rennlist.com/forums/928-foru...elections.html
Together with Greg Gray's work and some others - (lightweight internals, dry sump, crank drilling, .......)
I'll start a thread sometime down the line with all the particulars, but other than the plenum, I do not see where there is a problem. (even if necessary a different engine management system)
01-12-2010, 05:05 PM
#72
Drifting
like I said, I will do a thread sometime in the future, lightweight internals means easier to spin up to 7500, shape the piston or shave the head to raise compression near 11, bigger intake valve..........
In the mean-time
hey check this out, good info 80 grit sand paper and nice pics http://www.bonnevilleforum.com/showthread.php?t=267503
In the mean-time
hey check this out, good info 80 grit sand paper and nice pics http://www.bonnevilleforum.com/showthread.php?t=267503
01-12-2010, 05:38 PM
#73
Rennlist Member
thats not going to do it. we have some serious oiling issues that keep the rpm down for safety. the engines we have all built here can structurally handle the 7000rpm range, but its the oil that is the worry, not things flying apart.
much easier and faster to make an engine that can make big power between 4500rpm and 6500rpm. you want to make a GT3 cup engine out of a 928 engine?? knock yourself out. then, you will need to mate it to a $20,000 gear box that has close ratios to take advantage of the narrow, but higher HP peak.
wanna see what 420rwhp out of a 8500rpm blown S2000 looks like on the track, vs my 370rwhp , 6500rpm engine ? It is hardly fair. It wasnt until that platform got to near 500rwhp, that it was able to put a couple of seconds on me each lap. (another version of the same car) the 500hp verson of my car runs 3-4 seconds faster than that. No substitute for displacement in my opinion!
much easier and faster to make an engine that can make big power between 4500rpm and 6500rpm. you want to make a GT3 cup engine out of a 928 engine?? knock yourself out. then, you will need to mate it to a $20,000 gear box that has close ratios to take advantage of the narrow, but higher HP peak.
wanna see what 420rwhp out of a 8500rpm blown S2000 looks like on the track, vs my 370rwhp , 6500rpm engine ? It is hardly fair. It wasnt until that platform got to near 500rwhp, that it was able to put a couple of seconds on me each lap. (another version of the same car) the 500hp verson of my car runs 3-4 seconds faster than that.
No substitute for displacement in my opinion! like I said, I will do a thread sometime in the future, lightweight internals means easier to spin up to 7500, shape the piston or shave the head to raise compression near 11, bigger intake valve..........
In the mean-time
hey check this out, good info 80 grit sand paper and nice pics http://www.bonnevilleforum.com/showthread.php?t=267503
In the mean-time
hey check this out, good info 80 grit sand paper and nice pics http://www.bonnevilleforum.com/showthread.php?t=267503
01-12-2010, 08:03 PM
#74
Drifting
I like very much how my euro delivers power now where it comes on at 4500 and goes to 6200 pulling strong and sounding great. I would just like to extend that another 1000 rpms with the power increasing. I don't care about the track or beating anyone, just enjoying the ride the way I like it.
When I drive I spend a lot of time in those high ranges and it has always seemed fine.
Another 1000-1200 rpms does not sound like that big a deal and wouldn't this cure the oiling issue you are referring too. https://rennlist.com/forums/4962919-post47.html
When I drive I spend a lot of time in those high ranges and it has always seemed fine.
Another 1000-1200 rpms does not sound like that big a deal and wouldn't this cure the oiling issue you are referring too. https://rennlist.com/forums/4962919-post47.html
01-12-2010, 08:19 PM
#75
That would be fine. I wouldn't want to go past 6500 on old springs though. And the car breathes better up there if you make other changes.