BC Racing Time Attack Impreza #6
#91
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Appreciate that, but not what I felt though when I test drove one of the TD Billets several months ago (after driving the same car with the non billet). Nothing scientific, so perhaps my mind playing tricks on me.
Anyway.....
Anyway.....
#92
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"Size for size", billet wheels are "HEAVIER" than cast wheels, because billet aluminium is denser, there fore heavier than cast aluminium !
Even reducing the centre hub diameter does little to reduce the over all weight. So whilst you "may" be a few grams lighter, the extra lag/response from the increased surface area diminishes any benefit.
Reduced hub, & outside diameters is the way forward, if aiming to maintain a given power, as against increase it.
Mark.
Even reducing the centre hub diameter does little to reduce the over all weight. So whilst you "may" be a few grams lighter, the extra lag/response from the increased surface area diminishes any benefit.
Reduced hub, & outside diameters is the way forward, if aiming to maintain a given power, as against increase it.
Mark.
if thats the case why are you attempting to produce your own range of Billet turbo's.
Weighed a few last night for you......
18 G....standard 71g billet 48g
20 G....standard 72g billet 49g
35 R....Standard 120g billet 83g
37 R....Standard 132g billet 86g
They appear to be lighter by a long way to me, maybe the pig iron you are using is the problem.
Cheers
Kev
Last edited by The Gaffer; 01 March 2011 at 10:39 AM. Reason: Thought the word COPY was a bit strong
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Kev,
I'll try again.............
"Size for size", AKA, "dimension, for dimension", the average OEM grade billet aluminium is heavier than the average OEM grade cast aluminium.
Some grades will be almost identical in weight, based on the same volume of material, ie one cubic centimetre, but any differences will be a very small %.
So as I said, reducing the original wheel dimensions will reduce the overall weight, but the saving is due to "removing" material, not because the billet material is circa 30% less than cast, as you are suggesting.
Even reducing the weight of the wheel by a massive 30%, such as in the Blouch GT35R billet turbo you sell, and gave the above weights for, doesn't necessarily mean it will be less laggy, as shown here in the "back to back" graph you guys did, where it's lost spool up, BHP, & torque.
It clearly gives more power above 4500rpm, but that will be due the increase blade area, due to the reduced hub diameter, as discussed above.
So there's clearly more to it, than just weight reduction !
I'll try again.............
"Size for size", AKA, "dimension, for dimension", the average OEM grade billet aluminium is heavier than the average OEM grade cast aluminium.
Some grades will be almost identical in weight, based on the same volume of material, ie one cubic centimetre, but any differences will be a very small %.
So as I said, reducing the original wheel dimensions will reduce the overall weight, but the saving is due to "removing" material, not because the billet material is circa 30% less than cast, as you are suggesting.
Even reducing the weight of the wheel by a massive 30%, such as in the Blouch GT35R billet turbo you sell, and gave the above weights for, doesn't necessarily mean it will be less laggy, as shown here in the "back to back" graph you guys did, where it's lost spool up, BHP, & torque.
It clearly gives more power above 4500rpm, but that will be due the increase blade area, due to the reduced hub diameter, as discussed above.
So there's clearly more to it, than just weight reduction !
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Kev,
I'll try again.............
"Size for size", AKA, "dimension, for dimension", the average OEM grade billet aluminium is heavier than the average OEM grade cast aluminium.
Some grades will be almost identical in weight, based on the same volume of material, ie one cubic centimetre, but any differences will be a very small %.
So as I said, reducing the original wheel dimensions will reduce the overall weight, but the saving is due to "removing" material, not because the billet material is circa 30% less than cast, as you are suggesting.
Even reducing the weight of the wheel by a massive 30%, such as in the Blouch GT35R billet turbo you sell, and gave the above weights for, doesn't necessarily mean it will be less laggy, as shown here in the "back to back" graph you guys did, where it's lost spool up, BHP, & torque.
It clearly gives more power above 4500rpm, but that will be due the increase blade area, due to the reduced hub diameter, as discussed above.
So there's clearly more to it, than just weight reduction !
I'll try again.............
"Size for size", AKA, "dimension, for dimension", the average OEM grade billet aluminium is heavier than the average OEM grade cast aluminium.
Some grades will be almost identical in weight, based on the same volume of material, ie one cubic centimetre, but any differences will be a very small %.
So as I said, reducing the original wheel dimensions will reduce the overall weight, but the saving is due to "removing" material, not because the billet material is circa 30% less than cast, as you are suggesting.
Even reducing the weight of the wheel by a massive 30%, such as in the Blouch GT35R billet turbo you sell, and gave the above weights for, doesn't necessarily mean it will be less laggy, as shown here in the "back to back" graph you guys did, where it's lost spool up, BHP, & torque.
It clearly gives more power above 4500rpm, but that will be due the increase blade area, due to the reduced hub diameter, as discussed above.
So there's clearly more to it, than just weight reduction !
Hi,
We have never stated that the billet alloy is lighter we have always maintained its the amount of material that's removed which leads to its 33%, on average, weight loss.
The fact that the wheels are CNC cut gives the blades a more aerodynamic profile hence they shift more air .
When can we look forward to "Turbo Dynamics" billet turbo's ?
regards
Kev
#95
Just out of interest Kev... when you are showing the back to back tests like that, there is only one set of variables shown... which set are they and how do we get to see the figures for both runs as presumeably there was some time difference between them (turbo swap, and from the looks of it - 9 dyno runs) ?
ps - not doubting figures just curious.
ps - not doubting figures just curious.
#96
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Just out of interest Kev... when you are showing the back to back tests like that, there is only one set of variables shown... which set are they and how do we get to see the figures for both runs as presumeably there was some time difference between them (turbo swap, and from the looks of it - 9 dyno runs) ?
ps - not doubting figures just curious.
ps - not doubting figures just curious.
I will print them both off for you and post up tomorrow, run 4 was the best of the runs, car tweaked to do its max pre turbo swap.
Paul from Zen mapped the car before and after hence the number of runs.
The intake temps etc (variables) are always of the last run when overlaying traces, in this case run 9 the billet trace.
If memory serves there was a glitch refereed to as a dyno burp clearly seen on the blue trace.
cheers
Kev
#99
Hi,
I will print them both off for you and post up tomorrow, run 4 was the best of the runs, car tweaked to do its max pre turbo swap.
Paul from Zen mapped the car before and after hence the number of runs.
The intake temps etc (variables) are always of the last run when overlaying traces, in this case run 9 the billet trace.
If memory serves there was a glitch refereed to as a dyno burp clearly seen on the blue trace.
cheers
Kev
I will print them both off for you and post up tomorrow, run 4 was the best of the runs, car tweaked to do its max pre turbo swap.
Paul from Zen mapped the car before and after hence the number of runs.
The intake temps etc (variables) are always of the last run when overlaying traces, in this case run 9 the billet trace.
If memory serves there was a glitch refereed to as a dyno burp clearly seen on the blue trace.
cheers
Kev
No worries re posting the graphs up - would rather keep the thread for things that are involved with my car tbh rather than turbo wars part 4 lol
I remember the burp being discussed
Back to the project ..................................
The old MD321V that has served me so well for the past 3 years of sustained abuse is off the car and now down at Turbo Dynamics being checked over to see how it has faired with well above average mileage and above average power for that period. Faired very well from my inspections and initial checking
The new GT35/82 is sitting on my desk at the moment and new pipework is being made up at the end of the week so hopefully I will have the car back running again next week to run the turbo in and build a map for it.
I will use the dyno at Zen again for this as a good baseline against the previous set up.
Very excited about a power hike after being at roughly the same level for over 2 years now.
#102
Cheers Clive. I dont think it was ever quite at 600 though tbh. Made 591 on the V on saturday so 700 would feel ballistic ... not that just under 600 feels slow though
Lots of (small) things on the to do list but plenty of time to do them as no major stuff unlike last year, so am well on target to have the car ready for testing late march
Lots of (small) things on the to do list but plenty of time to do them as no major stuff unlike last year, so am well on target to have the car ready for testing late march
#103
A spare set of 2009 2.5 casing have been obtained and are currently undergoing work to strengthen them then it is built time again so that I have a spare full engine pre oulton that can be slotted in afterwards so that this one can be refreshed and kept on standby (hopefully) for the year.
#109
Cant wait to hear the rotated set up for the first time in anger.
Test day booked for oulton on the 25th so trying to get as much of the new set up done for them as possible so that there are only tidy up jobs between then and round 1 in complete contrast to last year where i was still bolting it together that morning for the first time .. that is the plan anyway LOL
On other developments ... got a range of hardrace suspension gizmos coming as I felt it was time to move away from the standard non polybushed set up and to enable more flexibility of set up for the rear of the car and more rigidity. Also fitting their front roll centre adjustment kit to replace the whiteline roll centre adjusters as they are due for renewal as a precaution. They look like a good pieces of kit.
Cheers to Bren @ Apex for sourcing these.
#110
Engine Specialist
I have to say Duncan, your car has always caught my eye more than others. I love the graphics and it helps that the Hawkeye is my favourite shape also! Good luck with the jump to 700!
Graham
Graham
#111
Cheers Graham.
Small update ====
Car and Turbo dropped off for the new up-pipe and downpipe to be made to fit the rotated turbo set up. very excited about this Gaz is going to do a cracking job.
While it is there we are also reversing the fmic pipework from the standard clockwise APS set up to enable shorter pipework and a cleaner routing.
Fingers crossed it will be sorted by next saturday to allow me to do some work on it and start getting it ready 8)
Small update ====
Car and Turbo dropped off for the new up-pipe and downpipe to be made to fit the rotated turbo set up. very excited about this Gaz is going to do a cracking job.
While it is there we are also reversing the fmic pipework from the standard clockwise APS set up to enable shorter pipework and a cleaner routing.
Fingers crossed it will be sorted by next saturday to allow me to do some work on it and start getting it ready 8)
#114
Yep i know .. disgraceful - they are going off to be powder coated before the start of the season They were the only wheels that had road legal rubber on.
Got some Pirelli arriving next week though hopefully to go onto the BC wheels so will get some proper posh pics done then with it all looking shiney
Got some Pirelli arriving next week though hopefully to go onto the BC wheels so will get some proper posh pics done then with it all looking shiney
#120
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I think you once said that you wouldn't be going rotated i hurry but you have faired very well for the last few seasons with a MD321V so i guess its now time to move on and get more power to be more competitive for your project.
Good luck for this and the following seasons Duncan.
Good luck for this and the following seasons Duncan.