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View Full Version : intake port volumn ( turbos vs. blowers)



badbug
01-19-2002, 12:48 PM
I want to know when building a twin turbo 526 c.i. engine for riding around and race use,does the port volumn matter in the same respect when using turbos as when using a blower. I have a ported set of -2 plus heads and was wondering if I should have bought a 2x or larger set of heads. Motor runs up to6800 rpm and quits pulling. Turbos are 60-1 hi-fi turbonetics. Camshaft is full roller 114 l.c.260intake @ .050 and 242 exhaust @ .050. 14 lbs boost

Infomaniac
01-19-2002, 08:18 PM
badbug I have seen lack of fuel flow cause them to quit pulling many times. Take a very close look at the fuel system. Especially the the supply line from the tank.

BOOSTDADDY
01-20-2002, 12:18 PM
badbug-infomaniac is on to something, be sure to check the entire fuel system, including the vents on the tanks.Be sure that you are not trying to run all the fuel through 1 regulator. A single regulator will not support the HP you should be making. As far as the heads they should not be a problem. Do you need more than 6800rpm? Any more RPM and Valve Train issues will turn up!
Good Luck!

schiada96
01-20-2002, 01:08 PM
I don't think you want a tt turbo to spin any more than 6500? I think most of the serious turbo engine guys like to load the motor down. More gear bigger prop

badbug
01-20-2002, 01:57 PM
Fuel system should not the problem. It is a full race mechanical with -12AN inlet and -12 outlet straight to the carburetor fuel manifold. 8 lbs. pressure and never drops. Outlet from tank is coming right off the lowest point of the v and back side of tank. I 'm thinking the turbos might have run out of volumn. Any Turbo Gurus out there?

058
01-20-2002, 06:21 PM
You didn't say if you are running wastegates, if you aren't then what is the exhaust housing A/R ratio? May be too small. What rpm are you looking for?

badbug
01-20-2002, 07:57 PM
I am running wastegates, set at 14 lbs. boost. I would think that at 14lbs. of boost I would be making in the neighborhood of 900-950 horsepower with a 526 c.i. engine.That should be enough to rpm amything I would think. I really need about 7200 rpms to get what I need out of my prop. Im not concerned with top speed as much as I am in e.t.'n in the quarter mile. Yes I am dragracing this 22ft. in-out.. Great fun!!

058
01-20-2002, 08:13 PM
I would check exhaust gas pressure in the manifolds, sounds to me like too much back pressure. Are you running a boost control valve like the Impco boost limiters or exhaust wastegates [where the excess ex. pressure is dumped?]

BOOSTDADDY
01-21-2002, 10:56 AM
BADBUG- CALL THIS GUY, HE IS THE TURBO GURU YOU ARE LOOKING FOR IN A MARINE APPLICATION. CARSON BRUMMETT (626)792-6410. THIS IS THE GENTLEMAN THAT PURCHASED THE GENTRY TURBO SYSTEM AND HAS MADE SOME IMPROVEMENTS ON IT!

VD CRUISER
01-21-2002, 05:48 PM
Badbug,
Drag racing the 22 footer? What hull and drive do you have, and what speed does it go?

badbug
01-21-2002, 09:45 PM
vdcruiser-So far the best speed I have reached with my 22ft. stryker v-hull is 107 mph with two people at 6800rpm's. Bravo -one with 1.5 gears, labbed 28 inch bravo one prop. Not looking for the fastest speed but the absolute quickest e.t. I can obtain in quarter mile. radar and gps accurate. no-bullshit here

HeavyHitter
01-27-2002, 07:25 PM
You're out of turbo. 526 is a big engine to feed with T-4 based turbo. Your exhaust pressure has got to be huge at 6800 rpm. Step up to some TA-45 or TV-71 sized turbos. I need to look at the compressor map but I bet your running way to the right below 60% efficiency.

HeavyHitter
01-27-2002, 07:54 PM
Badbug, looked up the compressor map. Those babies are good for 50 lb/min at a 2:1 pressure ratio. The crank will be seeing 923 hp max but since the turbos are way out at 60% Your available power will be in the 850 hp range. Your spinning those things pretty hard at 105,000 rpm. You can buy the next size up compressor to slow things down some but you'll still end up with high exhaust pressure. Turbonetics take compressor wheel off larger Garret turbos and makes custom housings to fit a small T-4 cartidge. That's great for smaller engines but when you get in the 500+ inch range you really need bigger turbine housings to keep the pressure down. I put together a 540 with Dart 360's and a pair of TV-71 with a 16 injector Hiborn stack manifold. The thing made 1500 ft-lbs and 2000+ hp. Took it to 7200 rpm on the dyno and the hp slope was still heading up. It pulls 7600 rpm in the land speed car it's in. That car made it's class record and has sat since. I'd love to try that engine in a boat.