[DeTomaso] Blow through carb for turbo

[wkooiman at earthlink.net]

I'm still amazed at the power increase with just 7-8psi.

I had a 2.3 Turbo Mustang GT.  It was like a cheap version of the SVO.  It could almost keep up with the 5.0.  My sister had a 2.3 Mustang non-Turbo.  It could almost keep up with my old granny.

I had a 93 Mustang Cobra.  It ran great for an everyday car, but it wasn't overpowering.  I added a Vortech (9psi), and it was like driving on ice.  Okay, maybe not quite that bad, but you get the picture.


-----Original Message-----
>From: Jerry R Knotts <knottsj at galstar.com>
>Sent: Mar 23, 2011 6:39 PM
>To: wkooiman at earthlink.net, detomaso at realbig.com
>Subject: Re: [DeTomaso] Blow through carb for turbo
>
>I have found Barry Grant carbs built specifically for blow through 
>applications.  They ave the sealed butterfly throttle axles and solid floats 
>also changes to handle the differnt pressures in the venturi.  Hopefully 
>they have all that figured out at this point.  I think 10 lbs is all that I 
>am man enough to use.
>
>Thanks
>----- Original Message ----- 
>From: <wkooiman at earthlink.net>
>To: "Jerry R Knotts" <knottsj at galstar.com>; <detomaso at realbig.com>
>Sent: Wednesday, March 23, 2011 5:32 PM
>Subject: Re: [DeTomaso] Blow through carb for turbo
>
>
>> There's a very good site that is dedicated to blow through carb turbos.
>>
>> There are several things to consider.
>>
>> 1.  You need to increase fuel pressure pound-for-pound to compensate, 
>> since you will be pressurizing the floats no matter what you do - with 
>> blow-through.
>> 2.  You need to worry about collapsing the brass floats, depending on the 
>> pressure.  Plastic floats can take more pressure.  I don't know how much.
>> 3.  If you don't use an enclosure, you need to modify the carb, or it will 
>> blow fuel out the throttle shaft.  There are several shops that will do 
>> the mod - they effectively add o-rings and they port unfueled air to 
>> equalize the pressure - so no fueled air escapes.  I'm not sure about the 
>> o-rings, but it makes sense.
>> 4.  If you use an enclosure, you don't need to mod the carb.  You can get 
>> them from Vortech or Paxton.
>> 5.  You'll have issues with fuel enrichment, since carbs are based on 
>> vacuum and not pressure.  I think the carb forum guys simply tune the 
>> secondaries very rich w/out power valves.  The thought being that they 
>> only hit the turbos when they step on it.  Probably close enough, but not 
>> optimal.
>> 6.  If you keep the boost reasonable, you'll have a lot fewer problems. 
>> 10psi should be easy enough.  20psi will break plenty of parts before you 
>> get it right.
>>
>> -----Original Message-----
>>>From: Jerry R Knotts <knottsj at galstar.com>
>>>Sent: Mar 23, 2011 3:41 PM
>>>To: detomaso at realbig.com
>>>Subject: [DeTomaso] Blow through carb for turbo
>>>
>>>For the collective.
>>>
>>>I have done fuel injection on superchargers and turbos using Fuel Metering
>>>Units and Adjustable Regulators.
>>>
>>>I am trying to save about $5000.00 by using a carb on my twin turbo
>>>Cleveland.
>>>
>>>Have a Lance Nist twin turbo set up for a 750cfm suck through that I am
>>>changing to a blow through.
>>>
>>>The carb for the 355 cu in is a 635cfm to 650, so will a 650 still work 
>>>for
>>>additional pressure from 6 to 10 lbs?
>>>Do I use an adjustable regulator so my pressure to the carb will go from 7
>>>to 17 lbs depending on the boost?
>>>
>>>I have blow off valves and exhaust releases controled by the valves.
>>>
>>>Will be running twin intercoiolers and maybe methanol injection.
>>>
>>>Your thoughts on the carb and fuel pressures needed.
>>>
>>>Thanks in advance,
>>>jerry ( my zip is E-I-E-I-O) knotts
>>>knottsj at galstar.com
>>>
>>>
>>>
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>> 
>
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