Coorvette

Hey guys,

I've been thinking of twin turbocharging my c5 z06 on a budget. With the price, reliability, and power potential I've seen from turbocharged ls1 engines, in my case it wouldn't make sense not to.
Due to how cramped the engine bay is, the only place the turbos could possibly be mounted without a lot of custom fabrication will be close to where the mufflers would be. This would be ideal, as I could retain the stock exhaust system, power steering system, alternator, ect ect. While the only disadvantage would be lower exhaust velocity and more intake piping and volume that would have to be pressurized before boost reaches the motor. As for an intercooler, i plan to use a front mounted intercooler and/or air to water. Methanol injection as well.

I have high HP goals, and the possibly of making 1000hp capable setup is appealing. However the engine is a mostly stock 350 c.I. right now and I'm not a good judge when it comes to matching turbocharger size.
So here's my question, on a mildly modified ls6, what size turbochargers should I be looking for to make the most power in the midrange and top end?
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Evil-Twin

A 1000 hp clutch is 3000 to 4000 dollars. You need hardened shafts, and at least a differential brace.. buying turbos and the plumbing for rear mounted turbos will quickly get you to ten grand...

Fast one

Squires offers a kit, ask them for a dyno graph; https://www.ststurbochargers.com.

Coorvette

I dont mean that iI need 1000 HP car, just that a ~1000 hp setup is appealing so that with a boost controller the power output could be set at any level with ease. I will be happy if it makes 500 to the wheels, with boost and all the mods it will have that shouldn't be hard at all. Only reason I mentioned 1000 HP is if I can make the setup with larger turbos, I wont have to change it much or at all down the road when I do spend more on things like the clutch. The main problem with that being lag, thus my question about sizing turbos and lag.

So to be clear, not 1000 HP, just inexpensive twin turbo. I've seen used c5 turbo kits for slightly more than I intend to spend and those don't include anything for fueling, tuning, or clutch. I think I can do it cheaper.

I have:
Wideband o2 sensor
Ls7 clutch, flywheel, and spacers, new clutch hydraulics
Fresh t56, torque tube, and rear end
Ls9 HG
ARP studs
Dual valve spring, Hardened pushrods, new lifters and buckets
Cloyes hex adjust and katech c5r timing chain
melling high volume oil pump

Coorvette

Good idea, there kit looks similar to what I what to do so the dyno graph could definitely be of use. Thanks for the feedback.

Also I apologize for all the grammatical errors, I am using my phone.

~Josh

Forced induction on a budget.

Coorvette

Let's try to keep this thread on topic, if you don't have anything useful to post then why comment. I appreciate the input about needing a stronger clutch, axles, diff brace, and the expense that comes with. as well as where to get a dyno graph of a similar system.

There are always used systems for sale, but paying $4,000 for a basic kit seems high. But $4,000 total new is inexpensive when you compare it to other new, and even used kits, and add up the stuff those kits don't include. Fuel, engine management, larger turbos, and other optional upgrades quickly ad up

Hopefully I can get more feedback from people who have experience with inexpensive turbocharging, ls engine or not. Other than eBay turbo sizing, info about cheaper ways to get any of the things listed that I still need is definitely appreciated.

I also just read about sts claiming a patent to all remote mount turbo systems, will be interesting to see if that claim comes up in this discussion or otherwise.

001pewter

alxltd1

Inexpensive is a subjective term, given what may be inexpensive to one is life changing to another. Budget is what you decide not others. That aside I am subscribing to see how you make out. Sorry, I have no experience to lend to the discussion but very interested. I don't think you will run into a patent issue unless you plan to market and sell what you finally put together, but that is an entirely different conversation. I have always been curious on how to avoid the lag from the rear location to the intake, but STS seems to have enjoyed major success with their systems so there must be some mitigating engineering to make it work well. Good luck and keep us updated.

Vetteman Jack

Good luck with your project. Will be interesting to see how it turns out.

1966ponyguy

The issue with this approach is boost itch. You say you would control the hp using a boost controller, however, a simple touch of the button "just to see" is too easy. You will soon be making 600, 700, 800, 900, ---- and parts will launch from under your car. I would either bite the bullet and build to the numbers I wanted or wait. If you are looking for 500 hp, you can get there cheaper without the turbos.

Just my 2 cents.

knewblewkorvette

I'm confused, you ask what size turbochargers you need then a few post down you say you already have two ebay turbos.

StatmanRN

I run a STS kit w upgraded turbos that I bought used.
There are advantages and disadvantages to the rearmount setup that Im sure you are already aware of.
STS does not have a patent on the concept of rearmount turbocharging as it was done before them
STS went **** up some time back. Turbo sizing/brand seemed to be dependant on what was on hand. THeir tunes were aslso suspect.
You will need a BOV IMO. Also I highly recommend an upgraded return pump such as TurboWerx
Even if you have fabrication skills and tools, if you factor in your time and frustration factor, I think you would be better off buying a used STS system.

zeevette

Totally agree. For one thing, the LS7 clutch is known to do the same thing as the LS6; pedal stick to the floor. Changing a clutch out is a really big PITA, so I would recommend something better. That's just one of many things you need to beef up to run over 500. You'll find out the hard way, or buy quality parts when you save up the money.

alxltd1

No it says "I need" then the list includes the turbos he is asking about. right after the melling oil pump

Velocity_Vette

My all time favorite rear-mount setup. I believe the car made in the neighborhood of 650-690~ HP. Owner sold the setup for a relatively small amount of coin all things considered.

ArmchairArchitect

These two forums may be of help:
https://www.homemadeturbo.com/
https://www.theturboforums.com/forum...urbo-tech.224/

Sounds like a fun project...I looked into it for my Mustang at one point.

The one thing I've heard about rear-mounted turbos is that they can lag, not sure if this is true or just theory though.

You may be able to figure out creative ways to free up room in the engine bay...eg. by removing the wiper fluid reservoir which really isn't needed.

bikeriderga

Speed always costs. How fast do you want to go?

Not trying to discourage you, but you really need to define your end goal before figuring up how much it is going to cost. 500 HP on stock internals boosted is possible and safe with the right tune and the right fuel. You will need to make sure you have the cooling nailed as forced induction produces heat (I only say this because you are looking at used plus potentially not buying a complete kit).

Once you start climbing into the above 500 RWHP club, you are going to need all of the supporting mods. You have a clutch that is safe to around 650 already installed. Not sure that includes new clutch master cylinder and slave, but let's assume it does. So now you are good to say 650 on the clutch.

Now you have to look at potential torque tube reinforcement, transmission reinforcement, and differential issues. Will a simple trans/diff brace suffice or is something else going to be required? What about torque tube? How many miles on her and what shape is she in?

650 RWHP is also going to put stress on your bottom end. especially on hard launches. Again cooling and fuel delivery are key here. How much of a gamble are you willing to take with stock engine and internals?

Over 650 HP you had better go forged bottom end, plus address all of the other weak areas. Realistically, even with you doing all of the work, you had better plan for no less than 15 K by the time all is said and done. If you do not spend it all , great! But if you are under that amount, you might be walking for a while.

Best of luck to you whatever you decide and let us all know. Experience is always the best teachers and I am sure all of us Vette fanatics are waiting to learn!

LoganExplosion

FAST. RELIABLE. CHEAP. <--Pick two.
I've seen cheap kits on trucks with great success. But never on a C5. Not saying it's impossible. But you'd be the first! Looking forward to your build thread.

MY03C5Z

My first thought as well. If the op wants a rear mounted turbo set up don't try and reinvent the wheel, go with an STS system new or used if you're on a budget.