LTG Power Upgrade Paths
By: Mark Gibson, Gibspeed Automotive Solutions
Let me start by saying this. I truly believe this platform is on the verge of a major breakthrough and major change in how owners view modding these cars. I’ve been through it before, I’ve seen other platforms, first hand, be stuck where we are today and I’ve seen the shift, once the right parts and tuning become available.
So with that said, I’m going to post this, which many will see as putting the cart before the horse, but I want people to have a real idea of where I believe the state of modding these cars will be… in the not-so-distant future.
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I decided to overlay some logs from the 4 main types of setups I support running on an LTG. Many others will give many other options, but these are the setups that make sense to me personally, after a lot of experience in this area.
1. Stock block, stock turbo, stock fueling - This is the way the car came, is extremely fun to drive, and plenty of real gains can be made with a tune and even more with e85, but no matter what, you'll have roughly the stock turbo power curve shown in the first log.
2. Stock block, BIG Turbo, Stock Fueling - This combo allows for moderate stock turbo-like Peak TQ numbers, with MUCH more peak horsepower and MUCH more area under the curve, while still operating with the limits of the stock fuel system. IMO this group of turbos start at a 5558, S252 size (52-58mm varients, etc) and go up from there.
3. Stock Block, BIG Turbo, AUX Fueling - This setup allows you to have slightly higher than stock turbo-like peak TQ numbers with MUCH MUCH MUCH more horsepower, especially up top, due to the added fueling capabilities. This setup is only limited by the stock bottom end and the size of the balls of the car's owner. IMO still a great option though. Making 450-485whp and 350-385wtq with a ton of power under the curve is easily attainable here. 55mm+ for these. So 5558, 6062, S257, EFR 7163 or 7670, etc.
4. Built Motor, BIG Turbo, Aux Fueling - This setup is pretty obvious. It allows for everything in #3, without the limits of the stock bottom end. I really don't see going for anything smaller than option 3, but now you open up the opportunity to run some of the big boys for 650+ whp. This would include the 62 and 6466, S300 series, EFR 8374, etc.
Now with all that said, on to my entire point here. In the graphs below you will see very clearly why I advocate these 4 options. For everyone scared about losing TQ down low and having a "Slow" spooling Big turbo...
The stock turbo car below makes peak TQ from ~3600-4300rpm and EVERY one of the big turbo graphs below eclipses the stock turbo’s peak TQ number between 4k and 4200rpm and holds that TQ all the way to redline. You do the math.
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Bottom line, if you want to drive your car like a stock turbo car, keep a stock turbo on it and enjoy the stock turbo curve. If you want something other than a stock turbo curve, I urge everyone to stop worrying about turbos being too big, spooling too slow, being laggy, losing transient response, etc etc, Get an *actually* big turbo and enjoy. Turbos below go from Stock-->5858-->6266-->6466
Big Turbo Sizing Guide
I put this table together a while back, when I first started trying to decide the best setup for the exhaust manifolds for the platform and I think it's some good, consolidated info for anyone considering a turbo upgrade.
Anything listed as "V" for v-band, whether IWG or EWG, is what I'm building the manifolds around and anything in Green is a turbo I believe to be the best option for the vast majority of the platform. The ones in Blue are what I believe to be the best options for someone with a built engine, shooting for big numbers, but I've also had great luck running lower boost, very efficiently, on less modified cars as well.
My "Best options" take into account price, size, flow, etc.
