How about using a plate type nitrous system. They are designed to spray extra fuel in addition to nitrous.You would use it just for the fuel. They are designed for carb applications and would work with low pressure fuel pumps. In its simplest form the solenoid could be set to open at full throttle or a certain rpm. You could also probably set it up to work with a fuel pressure regulator that varies fuel based on manifold pressure. Yes, there is such a thing. Another way to vary fuel output could be to hook it up to one of the nitrous computers that vary output based on rpm

[ 12-14-2001: Message edited by: bck ]

[ 12-14-2001: Message edited by: bck ]

bck - The nitrous solenoids that pulse according to RPM (progressive, soft nitrous) are another good idea. But I like the electric Holley better. Here's why. The carb can be jetted to handle the WOT full boost condition, the problem is part throttle jetting is then too rich and the transition to WOT is bad. To handle this with solenoids they would have to be pulsing at part throttle, which is 95% of the time, and they likely wouldn't last. Get more sophisticated injectors and now you've fuel injection.

The simplest setup is a pressure modulated power valve, but you would have to make it from scratch. The electric Holley was manufactured at one time, and could be modified to vary fuel according to RPM or pressure with fairly simple electronics. Asking around, I'm told that Holley's Mile-a-dial system used a small servo motor that moved a rod in and out of the jets. I don't know how the Quarter mile system altered PVCR size. I'm going to post on the General forum to see if anyone knows or still has one of these systems on the shelf.

Been thinking about this again.

bck - I was too quick to dismiss your idea about using the nitrous plate with a progressive controller. I was thinking of pulsing the solenoids all the time at part throttle and they won't stand up to that.

The best method would be to use the plate as a tertiary system for the top of the boost/RPM range. In this range the fuel flow rate can be varied according to boost/RPM and (I hope) be fairly close to matching the air flow rate. Then the primary and secondary circuits in the carb can be tuned to handle part throttle and medium boost transition without the obscenely rich jetting that is needed now to cover WOT.

NOS has a progressive controller, designed for a throttle position sensor, that will control a single plate and 200 HP solenoid according to a 0-5 voltage signal. At 2.5 V flow starts, max flow is at 4.7 -5.0 V. I assume that this is somewhat adjustable on the controller, probably to match the opening of the secondaries.

The TPS won't work in the blowthrough application since a sudden throttle opening would trigger excessive enrichment, so we need a boost sensor that delivers this voltage range with say 0-7 psi. The low psi in the box at part throttle should not trigger fuel flow. But between 3.5-7 psi - proportional fuel flow.

The primary PVCR and power valve may still have to be adjusted to be able to deliver both a clean, lean low end, and sufficient fuel for the low boost in the box at part throttle. Secondaries could be much leaner than before, but rich enough to handle medium boost transition.

Does anyone know where I can get such a pressure sensor? Does an electric fuel pressure sender deliver a voltage signal to the gauge?

I have been thinking about your pressure sensor/controller issue. There are boost enhancing systems on the market that vary waste gate action by means of an electronic pressure monitor and some type of solenoid in the waste gate line to fool the waste gate into believing there is less manifold pressure than there really is-this allows you to dial the turbo boost higher. They are sold in the aftermarket for Japanese turbo cars and should be pretty easy to find. If they open a solenoid then modifying it to your purpose should be easy. I'll surf around and see if I can come up with a link.

Here is a start:
http://www.racesearch.com/CGI/racese...iption_id=1682

I have a friend, I will try to go over to his house this weekend to verify his setup & take some pictures of it. What he has is a fuel enrichment system that has a hobbs pressure switch in intake. When motor intake goes in boost the pressure switch closes & a solonid valve starts injeting fuel into the carb. He adjusts the fuel by, (1) a holley jet in a machined adapter & (2)by an adjustable pressure regular. I remember when he was testing he would mess with the fuel presssure & sometimes he would open up this adapter in middle of his hose & change jet. I thing the idea of the boost refrence regulator would be a good idea, more intake pressure (boost) more pressure = more fuel in engine.

I think what insptech is talking about is what I had on my turbo motor. I had a pressure regular at the dash & I could raise or lower the max boost the engine would receive. The way it worked is the wastegate had a 5lbs spring pushing closed the valve that would let exhaust bypass. On oposide side of the diaphragm is where the intake boost was plumbed in. Tapping off the intake side, going to a pressure regulartor, then plumbed to the side with the spring. If I had the pressure regulator to zero then the boost would be 5lbs, regulator was letting out 1lbs then boost would be maxed at 6, and so on.

I think this will be the way to go. Carb set on its own to handle midrange, cruse speeds & when going it to boost enrichment system adds the extra fuel needed.

Holley carbs power valves can be made to work by ventingthem to out side the box takessome drilling and plumbing but it works.

PROBLEMS SOLVED!!!!!!!!!!!!!!!!!all you have to do is get rid of the prochargers, blowers and everything that requires a belt to fall off , break, and whine, and put a low profile twin turbo system with draw through carbs and all problems are over for good. They are especially a lot quieter to run . They are really so simple, I dont understand why more people dont run them.

To me, there's nothing like the simplicity of of cubic inches, less wear factor, less stress, easier maintenance, less crud on the engine(s)...i.e. pullies, gadgets, etc. Some of these blowers have up to 7 pullies with the serpentine belt running through them. It really cobbles up the appearance of an engine. With cubic inches you can monitor things much easier without complicating matters with superchargers, and these days the parts for cubic inches are much more available. I believe there's more reliability in cubic inches. Just my .02

Any possibility of connecting an MSD boost retarder up to some type of fuel metering.
The MSD box already measures boost and somehow retards timing on the distributer. Could it be used to do other things?