vettereddie

I'm working on a new project and trying to find the cheapest turbo kit available that's not complete eBay junk. Intercooler would be nice but hopefully not neccessary since it will be under low boost.

What I am looking to do is finally follow through on a twincharging project. I currently have a Greddy supercharger (uninstalled). I will be building the engine with 10:1 Wiseco pistons, crower rods, Toga bearings, port and polish on the head (free to me). The Greddy is a helical-screw positive displacement compressor, so feeding it 5-psi instead of ambient should be an additive effect. I plan on using the eManage blue and tC injectors unless bigger are needed. The Greddy s/c kit keeps the throttle body in the stock location, so any xB kit should mate fine if there is clearance on the rest of the charger.

The cheapest route would be to get a bigger pulley machined, and the next to run NOS. I am not doing this to stay low budget, just within it, and to have a unique, functional F/I system for next show year. So far I have found the Greddy without intercooler for $2245. I was hoping to stay under 2k, possibly 1500 for used. I'm just looking for 5psi out of the box. Last look customs had their barebones at $2650. If I can find someone local who can do the piping I might just go all custom w/ the OBX manifold and Garrett turbine.

equinox2355

hmm just my $0.02, but setup that way will be really inefficient due to the screw-type manifold supercharger. From a performance stand point (which you may or may not care about) when you do twin-charging with a supercharger and turbo, you typically want the supercharger to feed the air to the turbo, since the turbo experiences lag compared to the supercharger.

vettereddie

True, that's the way Eaton did it for VW on the Golf TSI. Unfortunately, I'd need to make an entirely new manifold, mounts, etc. to go that route. They also use aclutch drive to cut out the supercharger above 3500 RPM since above that the turbo is more efficient to get the same pressure.

Keep in mind that I'm not looking to do what VW did though. They wanted a stable pressure differential across the RPM band, so they start with just the blower under 1500, run both to 3500 and just the turbo above. I'm looking for an additive, not cumulative effect.

I'm not sure though if in a serial configuration loss would be greater than running just the supercharger though. It wouldn't be spinning faster and is still just compressing the same delta, the inlet air will just happen to be denser. What's the workload difference to compress from 5 to 12 psi (do not read as 0 to 12) vs. going from 0 to 7, it's still a 7 psi delta? I'd worry more about the inlet temperature since the turbo will heat it without an intercooler.

blown_xa

I would buy the greddy turbo kit and intercooler upgrade kit as well. You can always sell the e-manage that comes in the kit as brand new.

vettereddie

Yeah, but at $2300 I'd just sell the s/c and go all turbo with a bigger spring. It's looking like I probably won't be able to do this configuration within budget, though the "engine bling" would be off the charts with it.

I still want more power with the Greddy s/c, any suggestions. It A/FR was around 11.6 all the way across, I think I can bump it up a little bit on 93 octane. For pulleys, I could get a smaller one machined for the blower but then have a worse chance of belt slippage, or a bigger one for the secondary pulley on the alternator, but they would need to cut two radii (is that how you spell it), and I'm not sure of the cost. Also, the Eaton blower tops out at 14k RPM, not sure what the ratio is at right now but don't want to sieze the blower from thermal expansion. I've got digital calipers at work to try and figure out the final pulley ratio and derive RPM.

Of course, right now I'm leaning toward just a wet shot of nitrous. With tC injectors and forged internals, it should take it without issue, especially just using it at the track. just got to figure out if I want it running through the blower or tap the manifold after.

vettereddie

Just another thought, with an air intercooler on the s/c not really a possibility has anyone used meth injection? Especially if I go with a bigger pulley, I'd like to get the intake charge temperature down. Using it as a daily driver, I'm also wondering what consumption would be per 300 miles or so between fill-ups.

arizonaturbo

iTrader: (1)

If you want cheap.... I would go with a Revhard cast iron manifold (I purchased one for under $150.00 on eBay) and try finding a used Nissan SR20DET T25 turbo. You can usually pick one up for $100.00 - $150.00 on eBay, and maybe another $200.00 to get it rebuilt if it is in bad condition. This turbo will easily support 250 whp and will be a pretty good match to our smaller 1.5L motor. You can easily get turbine housing outlet flanges, oil inlet/outlet flanges and any associated T25 gaskets online pretty easily.

vettereddie

Yeah, I've been looking on eBay for components. Problem is I don't have a shop hookup to fabricate the downpipe, intake, intercooler, and all the other piping needed to do a turbo setup. I'd rather avoid the silicone couplers as much as possible, it's just another spot for a leak. Plus, I'd need to find a boost controller and other non-optional parts to run higer boost levels, and after adding in the cost of all the piece parts and labor to fabricate piping, I'm not sure it would come out any cheaper, and may be less reliable or lower performing.

I'm pretty capable after doing the supercharger install and a subsequent teardown and reinstall of the 1NZ-FE, but haven't messed with a turbo before and am just learning as I go. I'd rather not make some costly mistakes doing a homebuild if a kit has already adressed them. I'm assuming that's partly why you went with the Greddy kit instead of homebrew.

I'd love to find a used complete xB kit cheap but noone seems to want to let their turbo go.

vettereddie

Apparently the cheapest is a used Greddy turbo kit w/ eManage. Finally got one for near my target price of $1500.