Vitesse Stage 4 Turbo For Sale, NEW
12-02-2006, 06:08 AM
#46
Originally Posted by 333pg333
Well that's interesting as my K26/8 is about 3700-3800 for 1 bar provided I can trust my apexi ebc and my stock tacho. Also a very good point that seems to get severly neglected here. TRACTION. There is a proliferation of people saying that we should look for low down torque instead of upper range hp, but how much is too much? If we have all this power down low and run out of puff up top how do we put it onto the road? Mid-upper is my new catchcry.
12-02-2006, 07:11 AM
#47
Originally Posted by 333pg333
Well that's interesting as my K26/8 is about 3700-3800 for 1 bar provided I can trust my apexi ebc and my stock tacho. Also a very good point that seems to get severly neglected here. TRACTION. There is a proliferation of people saying that we should look for low down torque instead of upper range hp, but how much is too much? If we have all this power down low and run out of puff up top how do we put it onto the road? Mid-upper is my new catchcry.
No - this is false logic.
You are trading a large part of powerband for traction. The 944 likes to make torque - the lower the better.
By doing it this way, you have zero control. If you have the bottom end power, YOU are in control. You have many modern means of assistance - gear-based boost, traction control, LSD, soft tires, soft shocks,etc.
If you are having any REAL tracton issues with the tiny turbocharger on your car, there are other mehanical issues that should be a priority.
12-02-2006, 08:11 AM
#48
Rennlist Member
Fac, well I don't have any exhaust mods and I could have a clogged cat for all I know + it's hard to be accurate when you're driving and looking at a smallish screen that may not be accurate itself.
ST, my point being that I thought that by having too much power concentrated down low that there could be traction issues. There are people who chase high end power and others who scorn this by saying it's not usable power and we should be chasing low down torque and 1 bar before 3000rpm. I was also referring to higher hp motors in view of traction worries. I've heard of people saying over 400rwhp and they're spinning wheels in 3rd gear etc. I don't want that kind of power when I do my upgrades. I want to really be able to apply plenty of power coming out of corners on the track which is where my focus lies. I will be going up in capacity to a 3.0 I think which should enhance torque to a degree as well. Oh, and I'm not having traction issues a.t.m. in fact my suspension is faster than my engine currently. I'm hoping to balance that out soon.
Patrick
ST, my point being that I thought that by having too much power concentrated down low that there could be traction issues. There are people who chase high end power and others who scorn this by saying it's not usable power and we should be chasing low down torque and 1 bar before 3000rpm. I was also referring to higher hp motors in view of traction worries. I've heard of people saying over 400rwhp and they're spinning wheels in 3rd gear etc. I don't want that kind of power when I do my upgrades. I want to really be able to apply plenty of power coming out of corners on the track which is where my focus lies. I will be going up in capacity to a 3.0 I think which should enhance torque to a degree as well. Oh, and I'm not having traction issues a.t.m. in fact my suspension is faster than my engine currently. I'm hoping to balance that out soon.
Patrick
12-02-2006, 09:21 AM
#49
Three Wheelin'
Join Date: Sep 2004
Location: Tennesee
Posts: 1,269
Likes: 0
Received 0 Likes
on
0 Posts
The one thing that always frustrated me with past and present turbo vehicles
was waiting for the boost to kick in.
Although when the boost hits it's a great feeling.
With my 951 with stock turbo I was always frustrated when coming out of a corner an having to wait for the turbo to spool. Then when it kicked in it would sometimes upset the balance of the suspension. It takes extra effort to drive it fast on track.
With my current turbo I've got power when I need it and I can modulate how I use it. There is no waiting. This gives me more control of the car.
My speed between the corners is quicker because I have the power sooner.
I also have none of the on/off switch effect of the turbo kicking in so I'm not having to correct for this.
For me I like having the power available and being able to control how I use it.
was waiting for the boost to kick in.
Although when the boost hits it's a great feeling.
With my 951 with stock turbo I was always frustrated when coming out of a corner an having to wait for the turbo to spool. Then when it kicked in it would sometimes upset the balance of the suspension. It takes extra effort to drive it fast on track.
With my current turbo I've got power when I need it and I can modulate how I use it. There is no waiting. This gives me more control of the car.
My speed between the corners is quicker because I have the power sooner.
I also have none of the on/off switch effect of the turbo kicking in so I'm not having to correct for this.
For me I like having the power available and being able to control how I use it.
12-02-2006, 04:54 PM
#51
Rennlist Member
Tedesco,
Looks nice but not sure how to read this? What is this saying to us?
Thanks.
Looks nice but not sure how to read this? What is this saying to us?
Thanks.
12-03-2006, 04:21 AM
#52
Three Wheelin'
Thread Starter
Tedesco, thank you very much for posting that! Just curious but, is the crossover and intake stock on that car? Also, what are the units on the graph? Are the bottom units boost pressure, and the left side units backpressure? If so, are the backpressure units in psi? Was the S75 using a #8 exhaust housing? Sorry to ask so many questions! 
It's not often that you find many informative charts for these components around here.
Is anyone even remotely interested in my stage 4 turbo? If someone isn't soon, I think I'm going to have to throw a T04 exhaust housing on it and put this thing on my 911 or something as this is starting to turn into a waste of time.
It's not often that you find many informative charts for these components around here.Is anyone even remotely interested in my stage 4 turbo?
If someone isn't soon, I think I'm going to have to throw a T04 exhaust housing on it and put this thing on my 911 or something as this is starting to turn into a waste of time.
12-04-2006, 10:17 AM
#53
Drive-by provocation guy
Rennlist Member
Rennlist Member
Join Date: Apr 2002
Location: NAS PAX River, by way of Orlando
Posts: 10,439
Likes: 0
Received 0 Likes
on
0 Posts
Ok, cool. And again, awesome info you bring to this forum as some here have a hard time rememebering there are other turbo cars and turbochargers OUTSIDE of the 951 commmunity
Yea, the #8 works for me as it gives quicker spool up than the #10, which is way more than I would need. Even now this is more turbo than I need, but it was a special situation with LR so I went with it. When we had some fairly cold mornings, I posted about hitting 17psi in 1st gear right at redline and I am only running 18-19 right now.
I figured I could run in the 20-25 range, which your saying the #10 would be 25-30. So that sounds about right. As I said, I am only running about 18-19 now as I have had other issues to deal with first before I could get out and do some good datalogging and starting turning up the boost. I am also very confident in 951MAXX chips, which I have now, for running in the low 20psi range.
I agree with most that the focus should not be all about top end, but in the same light, IMO, I don't feel it should be about super low end either. You want 100% top end, get a Supra. You want 100% low end, get a Corvette. I think a happy median for our cars, assuming it is somewhat modified, would be 1 BAR by 3,500- 3,600. So I am a few hundred off that and I can live with that. But for some that are/shooting for almost 1000 revs sooner, more power to ya, but again, is that shooting for "useable" power if the tires are always spinning and/or you have to make sure you are pointed straight before you hit the gas???
Yea, the #8 works for me as it gives quicker spool up than the #10, which is way more than I would need. Even now this is more turbo than I need, but it was a special situation with LR so I went with it. When we had some fairly cold mornings, I posted about hitting 17psi in 1st gear right at redline and I am only running 18-19 right now.
I figured I could run in the 20-25 range, which your saying the #10 would be 25-30. So that sounds about right. As I said, I am only running about 18-19 now as I have had other issues to deal with first before I could get out and do some good datalogging and starting turning up the boost. I am also very confident in 951MAXX chips, which I have now, for running in the low 20psi range.
I agree with most that the focus should not be all about top end, but in the same light, IMO, I don't feel it should be about super low end either. You want 100% top end, get a Supra. You want 100% low end, get a Corvette. I think a happy median for our cars, assuming it is somewhat modified, would be 1 BAR by 3,500- 3,600. So I am a few hundred off that and I can live with that. But for some that are/shooting for almost 1000 revs sooner, more power to ya, but again, is that shooting for "useable" power if the tires are always spinning and/or you have to make sure you are pointed straight before you hit the gas???
Originally Posted by Porschefile
On the S75 the main thing I am am unsure of, which could have a drastic effect on efficiency and max boost levels, is the hotside. I am not entirely sure, but the #8 hotside appears to me to be about the size of a Garrett ~.60a/r T3 exhaust housing (possibly a little smaller like ~.58a/r. I have yet to verify this, however if that's the case it would certainly make sense for the spool levels you are seeing and it would severely limit the ultimate hp that the compressor is capable of. Speaking theoretically, if an optimal size exhaust housing was used (figure a T3 .82 or larger) then this turbo would be capable of handling around the ~25-30psi level. However, at that point then the real question is can the rest of your setup handle it. With a properly sized hotside to minimize backpressure at higher boost (typically a T3 .82 or larger 1.xx a/r, also probably at least a stg5 or t04 turbine), as I've mentioned before the S75 can produce airflow to support between 600-650rwhp at which point there are a ton of durability issues you'd be facing assuming you have all of the proper engine work to generate power at that level. So, please don't take my theoretical suggestions to mean that you should run 25+ psi as your engine might not be equipped to handle it yet for all I know. If the #8 housing is really only around the ~.60a/r range then I think you will start to max out closer to the 22-25psi range as you would then be seeing a huge amount of backpressure. I'm sorry I can't be more specific, but I am still not too sure on the sizing of KKK exhaust housings as they relate to the Garrett a/r standard that I am more used to. I think I will go do some research as this would certainly be good info to know.
If the #8 housing is really only around the ~.60a/r range then I think you will start to max out closer to the 22-25psi range as you would then be seeing a huge amount of backpressure. I'm sorry I can't be more specific, but I am still not too sure on the sizing of KKK exhaust housings as they relate to the Garrett a/r standard that I am more used to. I think I will go do some research as this would certainly be good info to know.
12-04-2006, 10:23 AM
#54
Instructor
Join Date: Oct 2005
Posts: 205
Likes: 0
Received 0 Likes
on
0 Posts
I probably should have posted some more details directly but I thought I did in the post that I did earlier:
The units on the graph:
-X-axle at the bottom- time in seconds
-X-axle at the top - RPM
-Y-axles: Pressure in the crossover tube, Pressure at the compressor outlet (turbo exit), pressure in the (stock) manifold. The units are BAR.
The lite blue line you can see it just a trigger that is activated whenever I pass a RPM mark, unfortunately I can not log RPMs with the same logger and two don´t work together.
The car has modified turbo inlte feed with MAF, stock inlet mani and stock crossover (neglecting splitting it into two). Exhaust is a special 3" one that I made myself and is without cat. The piping around the intercooler is new too.
So from the graph you can get the exhaust- to boost pressure ratio, the pressure loss between turbo (compressor) exit and inlet mani which includes the intercooler, throttleplate and pipes and the spool of the turbo (#8 hotside). I know that I have an exhaust leak too between crossover and wastegate because the gasket is broken into pieces and I think I am missing a few. I will do a propper flange some day. Max torque come at about 4200-4300 and I pass 1bar well below 4000 (moving avarag come retarded). The run was done on the motorway maybe 20°C (have to check) in fourth gear.
What I am still worrying a bit is that boost is not as constant as I would like it to be. I am useing an apexi controler and expected some better consistency. Might be linked to the exhaust that is leaking.
The units on the graph:
-X-axle at the bottom- time in seconds
-X-axle at the top - RPM
-Y-axles: Pressure in the crossover tube, Pressure at the compressor outlet (turbo exit), pressure in the (stock) manifold. The units are BAR.
The lite blue line you can see it just a trigger that is activated whenever I pass a RPM mark, unfortunately I can not log RPMs with the same logger and two don´t work together.
The car has modified turbo inlte feed with MAF, stock inlet mani and stock crossover (neglecting splitting it into two). Exhaust is a special 3" one that I made myself and is without cat. The piping around the intercooler is new too.
So from the graph you can get the exhaust- to boost pressure ratio, the pressure loss between turbo (compressor) exit and inlet mani which includes the intercooler, throttleplate and pipes and the spool of the turbo (#8 hotside). I know that I have an exhaust leak too between crossover and wastegate because the gasket is broken into pieces and I think I am missing a few. I will do a propper flange some day. Max torque come at about 4200-4300 and I pass 1bar well below 4000 (moving avarag come retarded). The run was done on the motorway maybe 20°C (have to check) in fourth gear.
What I am still worrying a bit is that boost is not as constant as I would like it to be. I am useing an apexi controler and expected some better consistency. Might be linked to the exhaust that is leaking.
12-04-2006, 10:30 AM
#55
Drive-by provocation guy
Rennlist Member
Rennlist Member
Join Date: Apr 2002
Location: NAS PAX River, by way of Orlando
Posts: 10,439
Likes: 0
Received 0 Likes
on
0 Posts
That graph pretty much matches the one dyno I had done and the power came on like an NA car.
A nice steady line going up and up and up.... Seemed like it would never stop making power!!
But, I still get the "slam back in the seat feel once it hits in the 15+psi range. The lag is from 0-10psi then from 10-20 the boost comes on real fast.
So, best of both worlds??? Yea, you could say that...That's what I am telling myself
A nice steady line going up and up and up....
Seemed like it would never stop making power!!But, I still get the "slam back in the seat feel once it hits in the 15+psi range. The lag is from 0-10psi then from 10-20 the boost comes on real fast.
So, best of both worlds??? Yea, you could say that...That's what I am telling myself
12-04-2006, 11:47 AM
#56
Instructor
Join Date: Oct 2005
Posts: 205
Likes: 0
Received 0 Likes
on
0 Posts
I would like to have a wider powerband. That is why I recently started to build a GT30R set up in combination with a 2.8L stroked engine for my track day car. I am willing to sacrifice a bit of the top end for that allthough I think that in the end it will end up at least at the same power as with my S75 street car. Considdering my driving skills I probably can enjoy it a bit longer before i have to rebuild the CAR. Will post a few pictures of the set up in the GT35R thread when I am back in a few days. Turbo location and crossover will be slightly different than stock.
12-04-2006, 08:31 PM
#57
Rennlist Member
I agree with you here Todd. Somewhere in the middle to upper is good. Especially if one goes up to a 3.0 conversion which will provide some extra tq anyway.
Originally Posted by toddk911
Ok, cool. And again, awesome info you bring to this forum as some here have a hard time rememebering there are other turbo cars and turbochargers OUTSIDE of the 951 commmunity
Yea, the #8 works for me as it gives quicker spool up than the #10, which is way more than I would need. Even now this is more turbo than I need, but it was a special situation with LR so I went with it. When we had some fairly cold mornings, I posted about hitting 17psi in 1st gear right at redline and I am only running 18-19 right now.
I figured I could run in the 20-25 range, which your saying the #10 would be 25-30. So that sounds about right. As I said, I am only running about 18-19 now as I have had other issues to deal with first before I could get out and do some good datalogging and starting turning up the boost. I am also very confident in 951MAXX chips, which I have now, for running in the low 20psi range.
I agree with most that the focus should not be all about top end, but in the same light, IMO, I don't feel it should be about super low end either. You want 100% top end, get a Supra. You want 100% low end, get a Corvette. I think a happy median for our cars, assuming it is somewhat modified, would be 1 BAR by 3,500- 3,600. So I am a few hundred off that and I can live with that. But for some that are/shooting for almost 1000 revs sooner, more power to ya, but again, is that shooting for "useable" power if the tires are always spinning and/or you have to make sure you are pointed straight before you hit the gas???
Yea, the #8 works for me as it gives quicker spool up than the #10, which is way more than I would need. Even now this is more turbo than I need, but it was a special situation with LR so I went with it. When we had some fairly cold mornings, I posted about hitting 17psi in 1st gear right at redline and I am only running 18-19 right now.
I figured I could run in the 20-25 range, which your saying the #10 would be 25-30. So that sounds about right. As I said, I am only running about 18-19 now as I have had other issues to deal with first before I could get out and do some good datalogging and starting turning up the boost. I am also very confident in 951MAXX chips, which I have now, for running in the low 20psi range.
I agree with most that the focus should not be all about top end, but in the same light, IMO, I don't feel it should be about super low end either. You want 100% top end, get a Supra. You want 100% low end, get a Corvette. I think a happy median for our cars, assuming it is somewhat modified, would be 1 BAR by 3,500- 3,600. So I am a few hundred off that and I can live with that. But for some that are/shooting for almost 1000 revs sooner, more power to ya, but again, is that shooting for "useable" power if the tires are always spinning and/or you have to make sure you are pointed straight before you hit the gas???
12-04-2006, 10:03 PM
#58
Three Wheelin'
Thread Starter
Personally, I just like the rollercoaster feeling of having a significant difference between off boost and on boost pull. I have been in several 951's with different setups like k26/8's, k27/6's, VR stage 3, etc. I have to say, all of them pulled fairly smoothly and just didn't appeal to me because there wasn't that immediate "hit" of power like you get with a larger turbo. This is just my own personal preference but, personally I'm not all that concerned with getting as much low-end torque/spool as possible. I look at it from the viewpoint that I am not competing in some type of race class and I'm not winning any points by getting from stoplight to stoplight 5% faster due to low end. I drive my car for fun! When I put the pedal down, I want something to remember and that lingers in my mind when I'm not driving the car! Broad powerbands are great and all, though that just doesn't suit me. I guess I'm just moving the peak hp / dyno queen direction. I think I shall change my sig to reflect this.
Broad powerbands are great and all, though that just doesn't suit me. I guess I'm just moving the peak hp / dyno queen direction. I think I shall change my sig to reflect this.
12-05-2006, 09:21 AM
#59
Drive-by provocation guy
Rennlist Member
Rennlist Member
Join Date: Apr 2002
Location: NAS PAX River, by way of Orlando
Posts: 10,439
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by tedesco
I would like to have a wider powerband. That is why I recently started to build a GT30R set up in combination with a 2.8L stroked engine for my track day car. I am willing to sacrifice a bit of the top end for that allthough I think that in the end it will end up at least at the same power as with my S75 street car. Considdering my driving skills I probably can enjoy it a bit longer before i have to rebuild the CAR. Will post a few pictures of the set up in the GT35R thread when I am back in a few days. Turbo location and crossover will be slightly different than stock.
How much are you pushing the S75 on it???