True 15m^3 is close to 530 CFM but that is maxing the turbo out and even at 79% efficiency you may or may not get anywhere close to 350hp with our car. As it is, the STi guys don't get much higher than stock switching from the VF30, 34, 39, 22 to the PE1820.
The VF that you have has a major of 56mm and the 30, 34, 39, 22 have a major of 60mm and are barely a 300 hp turbo as is. There is no possible way that a 56mm smaller VF anything can flow higher than a 460-490 CFM VF30, 34, 39, 22. It just isnt happening and that is not the VF8 map. The small VF's like the 8 and 12 are good for 225-275 hp and thats about it.
Well that sucks I found it when searching for a VF12 map.
What is the minor diameter of the higher VF__ turbo's.
As I understand it the inducer diameter is moreso the limiting factor of compressor flow.
And the larger exduced diameter widens the map.
I soon realised even with that map I posted that the MX6 would need to rev to over 7000 to get anywhere near 350.
And thats is at compressor speeds over 120,000.
Though I still think you are being a bit hard on the VF8 - VF12, isn't the T-bird good for upto about 250hp?
These are way larger than that.
I'll have another look for maps and see what comes up, but check your thread before posting.
no wai. It's only 3mm larger ID (39mm) than the Vj11 (36mm) with the same OD of 52.5mm. The Warner Ishi T Bird (IHI) is barely good for 225hp at the crank. The T Bird of that era also came with a T3 60 trim in .48 and/or .63 A/R depending on STD or ATX tranny. That turbo is the same size as the VF30, 34, 39 and is good for 490CFM max or about 300+ hp, and on the STi most of that 300hp is 2.5L boxer with huge 100mm pistons. It's a V6 in a 4cyl.
It's only 3mm larger ID (39mm) than the Vj11 (36mm) with the same OD of 52.5mm
Yeah the T-bird is but the VF12 another 6mm larger ID than that and 3.5mm larger OD.
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and on the STi most of that 300hp is 2.5L boxer with huge 100mm pistons. It's a V6 in a 4cyl.
Yes it helps but an engine does not determine a compressors flow. Just how much of it can be utillised.
Therefore a 300hp car must have at least a 300hp turbo. Nitrous and ram fed race engines capable of greater than 100% VE aside.
As I have said before the VF12 is known to be good for upto 220kw (295hp)
Sure thats on a 2.5Lt engine that can use more of the avaiable flow.
But as said 295hp car = at least 295hp turbo. And you can't tell me that a 2.5Lt Liberty has greater than about 85 - 90% VE.
It would be a matter of using quite high boost 18-22 psi on an MX6 to do it.
And without a compressor map to know the rough compressor speed, I wouldn't do it just to be safe.
You asked if the T Bird was a 250hp turbo and I said no wai, it's only 3mm larger than the Vj11. You'd be ahrd pressed to find anything over 200+ish at the wheels witht he T Bird and that would be on 16-18 psi and maxing the turbo out. It's simply not a high HP turbo in it's stock form. I'll check some stats and see if I can match it to one thats close. I bet the VF8 and 10 and 12 are close to the VF40 and the VF23/24. I should be able to figure something out for a flow map just like I did with the VF39 to T3 60. They're basically the same map.
Sorry, I know were referring to the T-bird but I was just pointing out the relation to the VF12.
The compressor for the VF12 is a 4726 if I remember correctly.
So I would think it would be similar to the RHF5(55) 4626.
Obviously compressed due to being less capable of the high PR flow that comes with the higher speed compressor.
Thanks for the input it would be nice to have something to base my future choices on.
Such as; hp expecation, boost target, inlet piping size (although I have upgraded to mostly 2") & managment.
Last edited by mx_masta : 4-25-08 at 8:47.
Reason: Sorry for all the edits, I'm kinda tired.
I wish I did. I'm looking for specs on the VF23/24 wheel. or if I can find suitable sized wheels in say maybe a TDO4/TDO5 and overlay the map on the VF23/24 maps that I have. I'm thinking that the VF8, 10, 12 are going to be very similar in terms of flow to the VF23/24.
Do they not both the VF23 & 24 have a BRLL4626 wheel? Or are you looking for confirmation of that?
Thats what is writen on the maps you posted for both of them. Same map for both.
This one shows the compressor part# hand written though!
So it tops out at 12m3, about enough for 280hp on the right engine.
Here for shizzles and giggles I have plotted the demand points (@ 3000, 4000, 5000 & 6000) for the MX6 at stock boost and at 14.7psi onto the map.
Nice right through the meat of the efficency.
Now I don't know how much a VF8 / VF12 differs to that map but AUTOSPEED
and the 323 guys regard them as 300hp turbo's for some reason.
In the end I think I will just be running the VF12 at 15psi and going for about 250hp.
That works well because 330cc injectors top out at 250 as well.
So just a little more fuel preasure will be added for headroom.
I'd say no wai on 300hp, especially at the wheels. Maybe 225-275ish like I said. If they were really a 300hp turbo you would have seen some of the Legacy guys with 275-300hp VF8-12's a long time ago. And besides, wasnt that a 2.0 twin turbo anyways or was it a single turbo 2.5L?- that (TT) would explain 280hp if so. We don't get those here so I couldnt tell ya.
I'd say no wai on 300hp, especially at the wheels.
Yeah no way 300 @ the wheels. But I think it should be damn near perfect for 250hp.
As said thats as high as I want to aim beacuse I dont want to go fully programmable management.
And I don't want to hack it with huge injectors & FMU, etc. Just want to add a afpr for a bit of head room.
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And besides, wasnt that a 2.0 twin turbo anyways or was it a single turbo 2.5L?
No it was actually a 2.0Lt single (Liberty RS). I was originally under the belief that it was a 2.5.
It's Definitely 2.0Lt single turbo Austrailan delivered.
God I'd like to have a map for the BRXLL4726 compressor, but they are just too damn hard to find!
I'm curious about how much side clearance there is on the side of the ex wheel that you didn't dremel. How much off centre was it? If it was bad, it could ruin the thing totally, if it wasn't bad, it could be fine.
Not much at all about 5 minutes worth of grinding to get it to centre properly.
If I had to guess I'd say that it was about 0.1 - 0.2 mm off centre.
It definitely doesn't rub and boosts smoothly with no unusual noises. Definitely hasn't ruined it.
I haven't mentioned yet but this new turbo has netted me over 10% better fuel economy.
Because cruising at 115 - 120Km/h it is under the boost threshold of 3000rpm.
Mostly highway for the last 3 tankfulls but with plenty of overtanking and quick squirts.
Averaging 9.14Lt / 100Km highway (about 31mi / gallon). Dunno about the city numbers yet though thats this tankfull.
I'm curious about how much side clearance there is on the side of the ex wheel that you didn't dremel. How much off centre was it? If it was bad, it could ruin the thing totally, if it wasn't bad, it could be fine.
Thats what I'll be doing when I do mine for sure. The VF8's are hard to find to begin with, the one I found is in brand new condition. NoFnway I'm ruining it over someone elses math.
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