Twin turbo big block first test drive...YES!!

[M&W's72vette]

I finally got to drive my twin turbo project I have been working on every spare second since last november and its great!! I still have some carb tuning to do but it runs pretty good so far. I got it running and cruised around some to check out the fuel system, cooling system, ignition ect. Everything was good so I had it in second gear about 2000 rpm and floored it, at about 3500 the vac/boost guage jumped up to ten lbs boost and at 40 mph or so it totally roasted the tires, drifted sideways and promptly hit the 5400 rev limit. What a rush! This thing never had enough power to even come close to doing that in first gear before. As soon as it hit the rev limiter I let off the gas and heard this wierd whooshing noise and I shut off the key thinking that I had damaged somthing...coasted to a stop and looked everything over and couildnt find anything wrong. Turns out it was the blow off valve on the intake pipe...wierd sounding thing. I made a few more runs after some carb jetting and it pulled even harder. I made a few runs in third gear cruising at 2000 and stomping on it, when the boost comes up it feels like a rocket! You can feel the tires shudder but they dont break loose. I have 7 lb springs in the wastegates so I turned the boost control valve down to see if it was working right and went the wrong way and actually turned it up instead....(still learning how it all works). I had it in third gear again and floored it from about 2000 rpm....when the boost came up, the guage showed 15 lbs and at about 70 mph it roasted the tires again and started drifting sideways and immidately hit the 5400 rev limiter again which allowed it to get traction again. My friend and looked at each other in disbelief....we tried it one more time with the same results. What an animal! I have basically a stock 72 454 engine with a mild comp cam and torker intake, it also has stock pistons, rods, crank ect so I made sure I turned the boost controller the right way this time and am going to keep it under 10 lbs so hopefully the motor will last awhile. I got it back on blocks again fixing a couple of oil leaks and I just recieved the fiberglass sidepipe covers so I can see if I can make the 3 inch exhaust fit under them. I had straight pipes on it so far but its too loud for the street and I got to get some mufflers on it. Here is a pic of it, I used late model ford pickup panel air filters. and a friend made some stainless steel airboxes to fit them. I still have to get the hood on it and build some ducting to feed the filters fresh air from the windshield area. Sure is fun!

Mike

 

[Stallion]

WOW!!! :eek

Do you have more details on this project? Like pictures of the buildup? I would love to do the same thing with my 350. Did you have any space issues with the big block? Was it a lot of fabrication to get the turbos in there?

 

[M&W's72vette]

I didnt take very many pics of it till I was pretty much finished with it. On the drivers side I had to remove the vacuum tank to make room for the turbo, on the passengers side I had to take all the stock heater and a/c system out for that turbo to fit. I am going to use a vintage air system and it all fits under the dash anyway. After removing those things there was plenty of room for the turbos. I used heddman block hugger headers and hooked onto them with a 3 inch pipe that runs under the frame then turns up into the space between the firewall and inner fender where the turbos sit. The pipes are about one inch higher than the bottom of the oil pan so there is no problem with clearance underneath. From the turbo I ran a 3 inch pipe down and out under the fender then along the side of the car as sidepipes. For the intake system I used the panel filters mounted on either side of the carb feeding the turbos. From the turbos I used 2.25 pipes going foreward in front of the radiator then up over the radiator to the carb hat. I used mandrel bent u bends from summit, 7 three inch ones for the exhaust and 7 two and one half inchers for the intake and one three and one half elbow to hook to the carb hat. It all fit in the car very well and I can still have all the acessories on the motor too. With a small block it would be easy to do, but it would just take lots of time to fit everything. There is room to run the exhaust pipe from the turbo back under the car and hook up to the stock exhaust system if you wanted but I decided to try the sidepipe thing to see how much cooler the car be inside with it out from under the car.


Mike

 

[WayneLBurnham]

Outstanding!!!!

You even kept it carbbed!!! I hope to put an axial blower on the real engine, whenever I can even start on that Holy Grail, but never considered the effort to do turbos, let alone TWINS!!!

Incredible guy!!!

 

[SurfnSun]

Id turn the boost down some more....that stock motor won't hold up long at 10psi. Id shoot for about 5-7 or so, til youre forged...then go for 15-17!!!!!!

Nice work on the project that sounds awesome!

 

[SPANISHVETTS]

WOW

More pics please

 

[M&W's72vette]

I am redoing the exhaust to fit under my newly aquired fiberglass sidepipe covers, then I gotta rework the hood to get it to clear the carb hat, I am using a daytona style hood and am going to cut the raised center section and lift it from zero on the front to about 1 inch where the carb sits then reglass it back together and throw some red paint on it. It will be awhile before its back on the road again.