OK, This is gonna be a little different to your usual turbo discussions. I'v been mulling over a few ideas recently. I want to upgrade my turbos in the near future, after maxing out my stockies (yet to achieve this). However, I was thinking I dont want to introduce any more lag into the system, and would rather reduce lag if possible. So I came up with a few ideas: 1. Use an NA motor, and Auto turbos and cams (this was more an idea as an afterthought than anything). 2. VGT Turbos. I was under the impression that Porsche was the only maufacturer to use these in a gasoline engine, so I went searching for the model used. The best I could find out was that they are made by Borg Warner, and that they go for 10,000 pounds in the UK. They are not listed in the Borg Warner available products list and I cant find a part number for them. I cant even seem to find a damaged or wrecked 2007 911 anyone is trying to part out. I then discovered that dodge used VTG turbos on a 2.2 litre motor in 1989, The Shelby CSX. It used garrett VNT-25 turbos. These turbos are rare but you can still find them. Seeing as they were origionally used on a 2.2, I think they should be perfect for 1.5 litres a peice using moder tuning knowlege. Apparently they flow better than a standard T25, but with much less lag. I also see no reason you cant swap on a bigger compressor, as the VTG is active on the exhaust side. 3. Finally, maybe some sort of unequal sequential set up on each cylinder bank. Probably too complicated, but maybe worth looking at. Any opinions, especially regarding the Garrett VNT-25 turbos. Cheers
2. VTG ftw!! Twin vtg turbos on a vg30dett you will be wheelspinning from idle. No lag and if you can fit the dodge turbo it will be flowing plenty. 3. Twin sequential on each bank? Forget it. Zed engine bay is clearly not big enough.
I have seen plenty of other threads with aftermarket guys singing the praises of the VGT-25's on a variety of applications. From what this guy is describing, I'd say either he was using a way too small turbo for whatever he was running it on, or the vanes in the VTG were sticking, which can become a problem if non synthetic oil was used, or they were never cleaned. apparently carbon build up will make the vanes stick. Finally, while the VGT-25 was not origionally intended to use a wastegate, a potential issue of overboost had been identified and external wastegates have been fitted with with much success. I'm really keen to give these a try. I just hope rebuild kits are still available.
You may have trouble making it fit. There is another actuator hanging off the side of it, the stock wastegate actuators barely fit...
Stay well away from early VGT technology, they are plagued with issues. Also as Chrispy said, they are usually about 1/3 larger than a similar spec turbo so fitment would be a huge problem.
Ah, dammit. I was getting really excited about the idea. I guess its back to trying to find someone wrecking a late model 911 then.
Like Chrispy said, getting it to fit would be a nightmare. It took me whole day to get waste-gates to fit on T25/28 hybrids which are very close to stock size. There's only millimeters of space to play with. If you want to do something like this, you're better of using a straight 6. Lot more room to play with. Don't let this discourage you. Good to see someone thinking outside the box.
OK, I'm still going with this. Check this mob out of your keen: http://aerocharger.com/index.php Looks very interesting to me. Now, before anyone says anything, yes I know they are dimensionally large, and yes I know they are hella expensive when compared to say a Garrett GT28R, but I'm in no hurry so I'm happy to save a little extra, and play around with the configuration. Where there is a will there's a way. I just cant get past the idea of a lag free 320 rwkw. I have emailed the company for a recommendation on turbo size and I'll go from there. Oh, and for a refundable deposit, they will send you a mock up turbo to see if you can make then fit
Piss those pesky turbos of an blow it M8. All your, eeerrrrr.... *lag* issues will vanish instantly. You migh have fun fitting one tho but youll work it out if you have some imagination and can use a blue-tongued spanner. The 350Z Stillen kits fit under their bonnet neatly. One of the recent trucks I drove (Iveco) used a Holset VGT turbo. Watercooled and BB cored. It was a very very large turbo in overall dimensions for the particular job and they are worth around 7 grand each. As an aside, the turbo would continue to spin over, audibly for some 30 to 45 seconds afer engine shutoff!! L8r E
