Well to throw my 2c into the ring, I have fitted almost every turbocharger from a 3071 up to a T66 to a 1G, and helped with both Ron's gemini and Jamie's soarer. Here are a few facts:
If you want to make much more than about 250kw, forget trying to use the factory auto, it simply won't cut it, this is from disassembly and component strength inspection, and personal experience.
Cams can make more power everywhere, but at the small end of the scale. Slightly larger cams will make more power everywhere, after you get to a point, in the case of a 1G I'd say around 215@050" and 8.2mm of lift, you will start to lose bottom end power.
You can't have your cake and eat it to. WITHOUT spending a fortune that is. SO if you want more power, you need bigger turbo's and bigger cams, especially if you want 300rwkw, and want to sepnd as little as possible. If you spent 10K on the engine, and half of that being on the cyliner head, the other half on a built engine with 9:1 compression, then you could fit your GT30 turbo with a .63 rear housing, make full boost at 3500rpm, and your 300rwkw. But no one does, they want lots of power, little cost, so deal with lag if thats you.
Ron has had great success with stock 1G's making 400hp at the wheels. I personally have destroyed 6. I find their oil flow to the conrods to be poor, and it definately wasn't tuning that made them expire, it was always conrod bearings 1 and 6. I'd say keep you power goals around 260-270rwkw on stock engine, and your oil changed OFTEN.
A aftermarket computer is a must for anything over 200-230rwkw, if your trying for more than that, stop kidding yourself and get a 1/2J, if you can't afford a computer and to do it properly, then you can't afford to fix it when it dies from detonation.
Now to the positives. The 1G with some camshafts can swing to the happy side of 9000rpm without a care. The internal strength is great, you will not break this thing unless you have detonation or the bearings flog out. If you are fitting camshafts, get onto Performance Springs, they have springs off the shelf that I run a 9.7 on, and work a treat, they will work with any camshaft any person on this forum will prb ever play with
Turbo sizing..... WIth a turbo intake manifold fitted with an XF throttle body, and the factory butterflies removed, you can expect the following output and spool from various turbo's. Please keep in mind this is +/- 200rpm or so, as exhaust manifold design and camshafts play a role.
2871R garrett or KKR 380 = 230rwkw on 16-18psi.............3500rpm full boost
3071R garrett or KKR 430 = 250-260rwkw on 19-21psi.......4000rpm full boost
3076R garrett or KKR480 260-280rwkw on 21-23psi...........4300rpm full boost
3082R garrett or KKR520 280-300rwkw on 21-23psi ..........4800rpm full boost
3582R garrett 300-340rwkw on 23-30psi........................... 5300rpm full boost
T66/TO4Z 350-440rwkw,.......................................... ....... 6000rpm full boost
Keep in mind that although I list more boost for each stage, just because you fit a bigger turbo doesn't bring MUCH more power, the turbo doesn't just magically push the air in, however each step of larger turbo allows the engine to EFFICIENTLY make more power at each corresponding step by using a larger exaust wheel, and stops power hitting a wall, as each step of turbo prob would around the figures quoted. I have fitted most of the garrett turbo's, 4 different ones to my own engine, and the KKR range is just lining up wheel specs and a bit of an eductaed guess to get you in the ballpark. I have also worked these figures up to GT35 on stock cams, and based on the power figures I have made on a stock engine with stock cams.
Regards.......................................6BOO ST
Re: turbo upgrade for 1GGTE
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Originally Posted by TA-022
would this not require a 180 spin on the rear turbo?
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