gnx7

iTrader: (28)

I have a Turbonetics T-70BB turbo from a previous project (Buick GN) with a 4" compressor inlet and .85 A/R turbine side 3 bolt housing I was thinking of using for a 347ci LS1 buildup to go road racing with next year. Combo would be a stock LS1 block/crank with good rods/pistons/LS6 intake/ported stock TB, and ported stock LS1 or 6.0 heads. It may even be an LS2 block with stock LS1 crank (370ci) and the above combo for the larger bore and more cubes.

The turbo is rated at 785flywheel HP and being a ball bearing turbo I imagine spool would be great especially 347 cubes pushing it. I would be running 3:07 gears (Viper Dana 44)/T56 and should be about 3,000lbs with driver in my '93 RX-7.

Any disadvantages you can think of running this setup? How quickly do you think this would spool up with 9:1 to 9:5:1 compression?

Would this turbo be choking the motor? I wouldn't think so. My goal would be 650rwhp.

Any and all comments would be greatly appreciated. The thing I'm most worried about is keeping the coolant under control. I would be using a horizontally mounted radiator and vertically mounted intercooler with alchy/water injection for extra safety running 100 octane unleaded as well. I'm a fan of low timing big boost like good ol Mr. Duttweiller .

I'm using this year to gain confidence in my car 440rwhp on the road race courses and then next try to step it up a little more.

Thanks in advance,

-Mark

Mark C

That should be a fun ride.

Sorry I can't speak to spool on a single. The two Garrett ball bearing turbos that I have are silly fast spooling.

I would go lower compression, unless this is a pure track car, and you want to put that 100 octane in all the time. You could go 8.25/8.5:1, and have room to grow when you want to upgrade the turbo. I doubt that the spool would be appreciably affected. I'm a big fan of low compression and big boost.

Wow, 3.07....are you only going to use the first 4 gears? Too bad you can't switch it over to a close ratio 6 speed. That would go real well with your car.

JZ 97 SS 1500

iTrader: (2)

The turbo you are using will work just fine. I do recommend swapping the exhaust housing. The GN 3 bolt housings don't flow as well as a standard T4, and you would want a .96A/R anyhow. It will spool very nicely and will make the power #'s you want, not ideal, but it will most definitely work.

Jose

TTSSZ

iTrader: (8)

Is the turbo water-cooled?
The few turbo setups I’ve seen on road courses have been water cooled, BB turbos. TT Porsche’s ect.
You might want to go with the truck manifold setup. The cast manifolds will take more heating and cooling cycles then a welded set of headers.
Also might think about placement of the setup, try to get fresh air always hitting the turbo, and directing hot air from the engine compartment

1point3liter

the truck manifolds won't fit between the frame rails.

gnx7

iTrader: (28)

Thanks for the input.... I would go with twins... but that is more weight and more complexity with the downpipe routing and intercooler piping. I have (2) stock GN turbos that would maybe work well... but I'd rather go single I think. 3:07 gears to mainly keep the tires planted under boost in the lower gears. Turbos like engine load and with my light car I don't think I need as much gear out back to help with torque multiplication. 5th is a waste of time anyway on most road courses due to the huge drop in ratio from 1:1.

Depending upon boost/timing 9:1 compression would easily work on 91 octane for the street. It would also help to get the turbos to spool quicker and not make the motor such a dog when not under boost. 1 point in compression is worth probably 25rwhp.

If it is recommended to replace the housing to a 4 bolt and Q-trim housing higher flowing unit with larger A/R..... I may as well just get another turbo from the get go. Size the turbo to the combination a little better vs. band aid.

Water cooled is probably a better idea as well since it will be tortured for 20 minutes at a time. More plumbing! Great......

1.3liter.... the truck manifolds won't fit between the stock framerails.... but boxing them for more clearance could be the trick. Cheap and effective.... but heavy as a SOB. Wonder what it does to chassis rigidity?!?!

Plans are in the works.....

1point3liter

Let me know if you need truck manifolds, i have a pair hanging out in the garage.

It doesn't sound like you the right turbo for how much power you want to make. I have a PT74 .85 A/R i'm planning to use on my setup. It has a Q trim wheel and the PT turbine housings flow a bit better from what i've heard.
The static compression is sitting at 8.2:1 so i could probably use a bit more bottom end anyway. I'm really looking to use the car for more than just drag racing. Worst case, i'll swap if for a .96 housing if i'm not happy with the results.

Also, remember our cars are a good bit lighter than a fbody or vette so it's not as much of an issue if you fall short of meeting your power goals. Dyno numbers are just numbers. It'll haul ***.

I agree with you on the twins. The extra weight and plumbing is not optimal for our cars.

Got Me SOM

iTrader: (2)

ls1 turbo in a lightweight great handling rx7, WHAT! You will own that roadcourse! The only thing I would be concerned with is heat. In addition to water cooling the turbo's, I'd add an oil cooler too.

If you have vids of this ride please post up!

Drewman

iTrader: (10)

Yes it will.

Now, That's an understatement. I'm still scratching my head trying to figure out where I'm going to put one wastegate.

Drewman

iTrader: (10)

The passenger side isn't even close, and of course, you'd have to relocate the alternator to use the driver's.

I'm going to end up having to notch mine a little, or I might dent it with a hammer. Cutting and rewelding is probably a better idea though.
You just can't leave well enough alone can you Mark?

1point3liter

exactly what he said.

I could be wrong, but for some reason im remember hearing that the frame rail having some sort of honey comb structure inside.




i want mine to run, i haven't touched it in about 3 weeks.

Drewman

iTrader: (10)

I'll have to poke around a bit and see. I only need two 1"x1" squares of clearance to give me no issues.

I hear you. If everything falls into place mine should be ready next month. September is likely more reasonable target.

gnx7

iTrader: (28)

You guys know we can't just leave these LS1/FD's alone....

I'm pretty used to the power driving the car every day to/from work. I did manage to get the tingly feeling romping on it in 2nd around a corner and staying in it a little too long sideways the entire time....

Overall once in 3rd/4th I just want it to pull harder. This should be the ticket and if I need more power... just dump in some 116 race fuel and turn up the timing/boost for another 100hp. Or slap on a larger turbo.

Boost is good.... But I like how linear n/a engine power delivery is... I'll let you guys be the guinea pigs to see how realistic these setups would be for racing/daily driving.

I'm a little worried about cooling with 20 minute WOT sessions on road race course during the summer.

Oil cooler is in the works for sure.

Got me some- I should have some road racing vid from Aug. 6th when I'm at Sears Point (Infineon) in Northen California. It won't be as exciting as LG Motorsports footage... but should be cool.