[DeTomaso] Questions on 4v heads

Thomas Tornblom Thomas.Tornblom at hax.se
Wed Oct 27 02:25:08 EDT 2010


The compressor in my 10 kW heat pump draws around 2.5 - 3.5 kW input 
power, depending on condensation temperature. That provides heating for 
my entire house, including the garage, down to about -25 °C outside temp.

I don't see how you could move any more heat than that through the 
whimpy evaporator and condensor in a car AC system. And if you don't 
move the heat through these devices, the compressor would somehow have 
to emit the heat, and it would quickly melt IMHO.

A car cruising at steady highway speeds draws only a few tens of 
kilowatts for propulsion. Adding 5 extra kilowatts will definitely be 
noticeable. Had you added 25 extra kilowatts it would have been like 
someone suddenly hooking up a trailer.

Cheers,
Thomas


2010-10-27 00:44, wkooiman at earthlink.net skrev:
> Are they really that efficient?
>
> All I know is on the tired 3-cylinder 1-liter engine, you notice it.   It drains 5-10mpg, and slows the car down enough that I turn the turbo on (turn the a/c off) when I enter the freeway.
>
> -----Original Message-----
>> From: Tomas Gunnarsson<guson at home.se>
>> Sent: Oct 26, 2010 12:39 PM
>> To: wkooiman at earthlink.net, detomaso at realbig.com
>> Subject: RE: [DeTomaso] Questions on 4v heads
>>
>> I'd be surprised if the AC used as much as 25 hp. 5 hp maybe.
>>
>> Tomas
>>
>> -----Original Message-----
>> From: detomaso-bounces at realbig.com
>> [mailto:detomaso-bounces at realbig.com]On Behalf Of wkooiman at earthlink.net
>> Sent: den 26 oktober 2010 19:10
>> To: Rob Dumoulin
>> Cc: JDeRyke at aol.com; detomaso at realbig.com
>> Subject: Re: [DeTomaso] Questions on 4v heads
>>
>>
>> You can't use a fixed number like that.  The impact is a percentage, and
>> you'd have to be in an extreme case for those numbers.
>>
>> Case in point:  I also drive a Honda Insight (don't rub it in - i'm sick of
>> it).  It makes about 60hp and weighs under 2,000 lbs.  You can barely feel a
>> difference when you turn the A/C off, and that's probably a 25hp drain.  So,
>> effectively, increasing HP by almost 50% is noticeable - in the Insight.
>>
>> My experience has been that it takes about 50hp to feel a difference in an
>> average performance car.  The upgrades that are definitely worth it are, cam
>> change, tuneup, gears, blower, and anything that makes it more reliable.
>>
>> And, once you get to about 450hp, you can't enjoy the extra power on the
>> street w/out getting in trouble (with the law).  Once you get to about
>> 550hp, you can't use the power safely without slicks.
>>
>>
>> -----Original Message-----
>>> From: Rob Dumoulin<rob at dumoulins.net>
>>> Sent: Oct 26, 2010 5:49 AM
>>> To: wkooiman at earthlink.net
>>> Cc: JDeRyke at aol.com, detomaso at realbig.com
>>> Subject: Re: [DeTomaso] Questions on 4v heads
>>>
>>> My intake stuffers are one piece, so no risk of becoming loose.  I have not
>>> installed them yet, but think I remember reading that they act as gaskets.
>>> The exhaust are mounted with a regular exhaust gasket on each side of the
>>> plate.  Last weekend, I had to add three new exhaust manifold bolts to
>>> replace the ones that went AWOL.  I'll admit it was probably my fault for
>>> not going back and re-tightening them a few weeks after I initially
>>> installed the headers.
>>>
>>> I've heard people say that 10HP is like removing 100 lbs of dead weight.
>> If
>>> you could remove 200 lbs from your car, would you do it?
>>>
>>> Rob
>>>
>>> On Mon, Oct 25, 2010 at 9:00 PM,<wkooiman at earthlink.net>  wrote:
>>>
>>>> You guys didn't mention the negatives.
>>>>
>>>> The intake port stuffers can come lose and cause damage or at a minimum,
>>>> block flow and cause you to have to take it apart to fix.  Is it likely?
>>>>   Probably not, but it's something to worry about.
>>>>
>>>> What about leaks?  I don't know how well these things fit.  Can they
>> cause
>>>> intake manifold or header leaks?  I don't know.  Maybe.
>>>>
>>>> What about hurting performance?  It's possible that these devices will
>> hurt
>>>> performance.
>>>>
>>>> I honestly don't know if these are valid concerns.  If it were me,
>> though,
>>>> I'd focus on the easy/proven horsepower techniques.  You will never feel
>>>> 10-20hp with your butt-o-meter.  You WILL feel pain if a 20hp gadget
>> fails.
>>>>
>>>>
>>>> -----Original Message-----
>>>>> From: cengles at cox.net
>>>>> Sent: Oct 25, 2010 1:07 PM
>>>>> To: JDeRyke at aol.com
>>>>> Cc: detomaso at realbig.com
>>>>> Subject: Re: [DeTomaso] Questions on 4v heads
>>>>>
>>>>>
>>>>> Dear Jack,
>>>>>
>>>>> About twenty years ago I used MPG intake and exhaust port plates. While
>> I
>>>> thought that they made more power, that was mostly a hope and a guess and
>> it
>>>> was never measured. In my review of exhaust port plates, they are usually
>>>> described as improving exhaust flow and they usually *imply* improved
>> power,
>>>> but I could never find any dyno evidence of actual benefit.
>>>>>
>>>>> Recently Dan Jones' Great 351C Dyno project actually tested the MPG
>>>> Stinger Port "plates". They are bronze and have a solid tongue or stinger
>> of
>>>> brass that sits low on the floor of the exhaust port. Dan's dyno testing
>>>> showed (I am going on memory here and I have slept since he posted it)
>> only
>>>> about 5 horsepower improvement. It was way less than 20 hp.
>>>>>
>>>>> I think that properly used with a complimentary intake manifold and cam,
>>>> intake port stuffers can give an honest 20-30 hp. I think that the HP
>>>> benefits with the exhaust port stuffers is much more modest. [....but
>> five
>>>> hp *is* hp....]. Cost per the MPG website is $90 for a set of
>> intake&exhaust
>>>> stainless steel port plates and $175 for a set of Exhaust Stinger Port
>>>> Plates. Again, as I glanced at the website they allege 20 hp and 20
>> ft-lbs
>>>> improvement with their steel set, but not dyno sheets are shown nor
>>>> provided...........
>>>>>
>>>>> Warmest regards, Chuck Engles
>>>>>
>>>>>
>>>>> ---- JDeRyke at aol.com wrote:
>>>>>> In a message dated 10/25/10 7:19:04 AM, dave at damardirect.com writes:
>>>>>>
>>>>>>> Hi Jack,
>>>>>>> What is your opinion on exhaust port plates? W/o intake port
>> stuffers?
>>>>>>>
>>>>>> Never actually used either; I got lucky in 1990 and found a lightly
>> used
>>>>>> pair of SVO aluminum heads that already had closed chambers,
>> adjustable
>>>>>> valvetrain and raised ports. Generalizations are worth what you pay
>> for
>>>> them ($0
>>>>>> here), but my understanding on 351-Cs is,
>>>>>> 1)- intake port stuffers can make maybe 20-30 bhp extra (~10%) on a
>> real
>>>>>> 350+bhp engine, at some rpm levels, depending on the intake&  carb
>>>> they're
>>>>>> paired with.
>>>>>> 2)- Exhaust plates do less than intakes but can pick up maybe 10-20
>> more
>>>>>> bhp (~3-5%) on a real 350+ horse engine, again over certain rpm
>> levels.
>>>> Lots
>>>>>> of caveats- including starting with closed-chamber iron heads,
>>>> semi-equal
>>>>>> length headers and more open exhausts than stock Ansas. There are 2
>>>> designs I'm
>>>>>> aware of: cast-stainless or cast-bronze to take the heat, and are
>>>> bolt-ons
>>>>>> between the heads and header flanges, not welded, pinned or glued.
>>>>>> Port plates are Band-Aids for head design problems. Both intake or
>>>> exhaust
>>>>>> plates need replacement or at least tuning of other engine parts for
>>>> most
>>>>>> drivers to even notice them except that they may change the exhaust
>>>> note. A
>>>>>> couple of vendors sell these; I'd call around and ask them what effect
>>>> they've
>>>>>> seen on something like your engine- and have a parts list handy 'cause
>>>> they
>>>>>> will ask whats in there. FWIW- J DeRyke
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>>> --
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>>> 904.476.8744
>>> rob at dumoulins.net
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Real life:   Thomas Törnblom             Email:  Thomas.Tornblom at Hax.SE
Snail mail:  Banvallsvägen 14            Phone:    +46 18 32 31 18
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