gtb/gts turbo engine sounds and video

Her'es a 308 with a blower
http://mywebpages.comcast.net/markeberhardt/MarkFerrari.mpg

 

Coool video! Sounds awesome, what is the power of that car?

 

Thanks. It made 304 rwhp that day, so maybe 350-360 crank hp. It was at 10psi, manifold air temp of +260F (that's as high as the gage went), custom intake, eaton mp90 blower (roots type), no intercooler.

It has since been upgraded with a larger lysholm 2300 blower (screw type), water/air intercooler, 22 psi @ 125F. I plan to get to the dyno in a month or 2 when the weather improves, but the math says it shoyuld be at about 525 rwhp/620 crank.

 

Hello I am curious how I go about adding a blower to my 308GTSi. I've been taking care of it for a while and tried doing some digging around for a blower and was not able to find much so I never followed through. Thanks for any tips.

 

Coolyo, You have mail (I don't want to hijack Ricardo's thread).

 

That sounds sweet!

 

As a point of reference, Ive found my car to make about 13-15 whp per psi of boost (intercooled). (I am not sure of the blower efficiency vs my turbo, but they might be fairly close and with the air to water IC you have, it wont make much difference. The other wildcard is blower drive power, but for fun lets just say that has the same effect on whp as the exhaust backpressure increase with a turbo does.) So, with your extra 12 psi, theres over 150 whp right there.

The dropping of intake charge 150 or so degrees will add another nice healthy lump of power, probably gettting you close to your guesstimate.

Good luck!

 

I did the calculation base on air density in the manifold. I plugged in the 10 psi and 260F for 304 hp, then just used the idle gas law to calculate the change new density. Then assumed the % increase in hp was equal to the % increase in air density. I checked the calculation by plugging in 0 psi @ 80F and it predicted 240 rwhp, a stock QV is 200 and removing the CIS injection is supposed to add 35-40. So, I think it’s close to right.

I’m pretty sure blowers do better than turbos on a psi basis. A drive belt is about 90% efficient, a turbine is only about 65% and reduces flow which increases manifold pressure. The numbers I’ve seen make me think that 20 psi from a blower is about 24 from a turbo. We’ll see soon enough

The hp/psi thing will change with displacement too, what size engine are you talking about?

 

Interesting. Sadly the video, nor sound for that matter, works on my crummy computer... but your car looks great! Is that stock, or atleast a factory color paint, what about the wheels? Again a stunning car.

About blowers, it doesn't supprise me that they are more efficient... but how much power does it take to run one? Thats the only down side I've really heard about them. (That's what some ricer friends of mine say, their cars take so much power to run them that they see better results with turbos... what do you think of this argument or do you think they are just trying to put the wrong supercharger on?) Thanks for any input on this, I know little to nothing about blowers.

 

The color is stock, the wheels are from a ferrari 550.

The world of blower change significantly about 10-15 years ago with several key advances. The bypass valve was invented to unload the blower when power is not needed, like cruising. Very tight tolerance machining eliminated the need seals on the rotor and dramatically reduced friction and just as dramatically increased life. And the invention of the screw type blower increase the maximum practical boost without an intercooler from about 6 psi to about 12 psi and with an intercooler from about 12 to about 30 psi. There are a lot of systems that still use old technology, so not all blower systems are created equal.

The efficiency question is a tough one, it really depends on how you define it. Normally people talk about the compressor efficiency. In that case a turbo is about 65%, a screw type blower about 60%. But that is only part of the story. For a turbo charger, the total efficiency is the compressor times the turbine, so .65 x .65 = 42% For a blower you need to include the drive belt, so .60 x .9 = 54%, so it uses less power to get the same boost from a blower. The turbine losses for a turbocharger are often neglected because it’s harder to see where they come from. The turbine increases the back pressure in the exhaust and the pistons have to push against that pressure. The increased back pressure also means that the manifold pressure needs to go up by the same amount to keep the flow going, which means the compressor works harder. When sizing fuel injectors, you use about .45 lb/hp for naturally aspirated, .55 lb/hr for a blower, .65 lb/hr for a turbo. All three engines run about the same mixture, but the turbo’d engine needs more fuel because spinning the turbo eats more hp than spinning the blower and they are both worse than natural aspiration. 20 years ago, a blower system could only hit about 25-30%, but those days are gone. There is a reason that a lot of factories are now choosing to install superchargers, and 20 years ago none were.