Author Topic: max boost 9 psi? (Read 5358 times)

dennis m king · « **on:** May 13, 2006, 03:17:07 pm »

i spent the time to rig a boost guage and i get max of 9psi. what kind of boost do you guys run i am only showing boost staying up around say 40 mph. seems the car does not need boost to drive moderat and unlike my dodge truck the boost does not seem agressive. is this in the ball park for a pump set very close to stock output? i was hoping to see more boost at lower speeds but my pump is not cranked up anymore. it scoots along when above 5 psi. what do you guys think? now i want to see the difference with the turbo that was blowing oil out the exhaust. it made the car sound like there was a turbo on it. this turbo is very quiet.

RabbitJockey · « **Reply #1 on:** May 13, 2006, 08:30:01 pm »

my engine is supposed to be stock, and i can get my boost up to 12psi, so i kind of doubt it's stock. buuuut, like you said, anything past 5psi and really start to notice. 9 psi is more like what stock boost should be.

RabbitJockey · « **Reply #2 on:** May 13, 2006, 08:31:49 pm »

and like you said, under regular driving there usually isn't much boost. but i have noticed on the highway that i usually have a little bit like 3-6 psi, and on the high, it swings over to 12 pretty quickly before my wastegate or bov let's it out.

zagarus · « **Reply #3 on:** May 13, 2006, 08:39:29 pm »

mines still stock and is running 9 psi, no more. But that will change soon.

dennis m king · « **Reply #4 on:** May 13, 2006, 10:00:34 pm »

well i did some driving tonight and at 60 mph on a flat road no more than 2 psi to maintain 60 mph. so i am thinking it runs like the non turbo since they are rated at the same milage in mixed driving i think.but it pulls hills and goes faster when loading the engine.
now how to get 5 psi of boost driving flat at 60 mph? larger compresser spool? i am thinking better milage and performance.around 50 mph it goes to 10 psi fairly quick.
for the record i put on 13 gal of 80 waste veg oil and 20 regular gas and the boost seams to respond like diesel though i got about 4 oz of acitone in the veg oil also.

jtanguay · « **Reply #5 on:** May 13, 2006, 10:43:33 pm »

you actually want lower boost at cruising speeds. boost should only come on when you need it. your car only needs a set amount of HP to travel any given speed. Too much HP and its just unused diesel going out the exhaust. Uphill you just use your foot to increase boost and thus power

SMOKEYDUB · « **Reply #6 on:** May 14, 2006, 10:57:23 am »

according to bently factory max bos can be from 9.4 - 12.6 i believe. It depends on the driving conditions.

745 turbogreasel · « **Reply #7 on:** May 14, 2006, 04:19:21 pm »

I want max boost in all conditions.

Exhaust has to go through the restriction of the turbine wheel anyway.

Energy is lost as exhaust heat, but the turbo can reclaim some of that.

Any increase in inlet manifold pressure helps to overcome pumping losses, increasing efficieny.

More boost pressure will decrease EGT, and enhace the life of your engine.

It does not take more fuel to create boost, it just takes more favorable conditions inside your tubo...better exhaust, optimum tubo choice, and an effective aftercooler. A wastegate that doesn't start to open as you leave idle helps too.

Look at a TD generator or Sawmill, it is spooled up all the time. Why because it is more efficeint.

Wy is your car nnot that way? Because unless it is a hybrid, you must have a broad RPM range.
A smaller turbine will spin it up faster, but at a certain point, the compressor overspeeds and starts to create more heat than boost.
New cars wouldnt come with VNT turbos if we didn't need low end boost right?

My Jetta TD's Caddy made 9, and only in higher gears, trhere wasn't enough load/time in 1st to get things going.
The Volvo D24 hits 10.5 by 2900 RPM, and peaks at 11.5. AllI have done is a litle smoothing of the exhaust manifold. Stupid internal wastegate...
At 60 on flat ground it hovers around 5 PSI, and heads up pretty fast at the slightest hint of a grade.

The Dodge Cummins trucks are soo sweet because with their smaller rev band, the turbo is pretty well spooled up as soon as the torque convertor has stopped slipping, and the rediculous torque more than compensates for the kinda crappy RPM range. I mean no offense here, If I had a Cummins that revved to 5200 like the Volvo, I'd need new undies every day.

dennis m king · « **Reply #8 on:** May 14, 2006, 05:04:52 pm »

i can get max boost about 60% of rev range from third on up easy. at 60mph i run about 1 to 2 psi on flat road stand on it and it maxes out in about 2 seconds. i am use to my dodge responding to very slight throttle changes with instant boost(with in reason) changes but i am only dtiving a 70 hp car to about a 375 hp dodge diesel (39 psi on it hard no cargo) that sounds like the turbo in in the glove box. just wish it was more aggressive stock. i may do what you guys show to adjust the boost higher but that most likly not change the easy driving boost and fuel milage so i am not on a mition to do it .

maddog007 · « **Reply #9 on:** May 15, 2006, 03:49:08 am »

Umm.... My 1.9 TD is maxing at 12psi at the moment, using the make your diesel faster methods in the FAQ.

But im a little worried now after reading this thread.
When crusing on the highway my car runs a constant 9-12psi when traveling at 60mph to 70mph.
I thought this was normal ,but it doesent sound right. plus my fuel consuption is not that great compared to many others on here.

other wise the engine runs great .

?

jtanguay · « **Reply #10 on:** May 15, 2006, 04:54:38 am »

consider that to travel 60 mph your car uses around 20 hp. Good for fuel consumption. Now consider that your car is making full boost and the LDA is maxing out, so your car is pumping out a steady lets say.. 70 hp. Now if only you had higher gear ratio's to take advantage of the extra power, but stay at the same RPM? :shock:

thats why I think its better to just have low boost, but be able to have full boost on demand

also think of the added stress on the motor from running full boost on the highway. The turbo will definitely like working at a constant rate, but what about other engine parts?

RabbitJockey · « **Reply #11 on:** May 15, 2006, 07:09:15 am »

Quote from: maddog007

Umm.... My 1.9 TD is maxing at 12psi at the moment, using the make your diesel faster methods in the FAQ.

But im a little worried now after reading this thread.
When crusing on the highway my car runs a constant 9-12psi when traveling at 60mph to 70mph.
I thought this was normal ,but it doesent sound right. plus my fuel consuption is not that great compared to many others on here.

other wise the engine runs great .

?

1.9s have a smaller turbo and more displacement, i would assume that 9-12 psi is normal.

jwspin · « **Reply #12 on:** May 15, 2006, 11:21:59 am »

Boost comes with heat. if your engine is really hot and your exhaust cold then the heat is going to be drawn out. if you arent pushing your motor vey hard then there isnt any air being moved or heat differences so therefore you wont get boost. set your wastegate at whatever max you please then control the heat with the fuel pump. depending on the engine and turbo combo you will be getting boost at different engine loads and rpms.

-jared

dennis m king · « **Reply #13 on:** May 15, 2006, 03:25:13 pm »

Trev0rbr:
are you smoking like you are actually running high egt to do the speed limit? the 1.9 is bigger but i would think it would have most of the 1.6 traits sort of. more fuel makes more boost which brings down the egt. i think for big trucks 4 psi = 100 degF lower egt. the 1.9s turbin housing maybe smaller for the displacement than our 1.6 housings. anyone got a 1.9 to tell what boost at 60 mph?

RabbitJockey · « **Reply #14 on:** May 15, 2006, 07:48:49 pm »

i quoted what he said, my car has an unmodded 1.6td

Author Topic: max boost 9 psi? (Read 5358 times)

745 turbogreasel