pressure regulator

i am working on my blow thru setup and was wondering if anyone knows of a valve i could regulate my pressure to "trick " my msd 6btm to think at 5 pounds of boost that it is only seeing 1 pound than from that point it could be 1-1 pressure so it reduces my timing 1-3 degrees per pound of boost ?
thanks

Maybe some kind of pneumatic poppet valve between the BTM set at 4 PSI?

It's not exactly what you are after because when the poppet valve opens at 4 to 5 pounds of boost you will loose 4 to 5 degree's of timing instantly, if set at 1 to 1. It will delay it though, and you can go 1 to 1 or whatever setting you chose.

Maybe you could compensate with a little higher intial timing setting, if you are after lower boost drivability/power?

Just an idea

If you are planning this for the SR-71 deal the upside is your timing widow is likely between 17 and 27 degree's total timing, I would think, so only a 10 degree window to deal with anyway.

https://www.google.com/search?q=adjustabe+air+pressure+poppet+valve&oq=adjustabe+air+pressure+poppet+valve&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIKCAEQABiABBiiBDIKCAIQABiiBBiJBTIKCAMQABiiBBiJBTIKCAQQABiABBiiBNIBCTM5NTM3ajBqN6gCALACAA&sourceid=chrome&ie=UTF-8

why yu say timing window from 17to 27 you think with 20 # boost i only need to retard my timing to 17 max? or even 30 pounds boost ?

supervel45 wrote:Maybe some kind of pneumatic poppet valve between the BTM set at 4 PSI?

It's not exactly what you are after because when the poppet valve opens at 4 to 5 pounds of boost you will loose 4 to 5 degree's of timing instantly, if set at 1 to 1. It will delay it though, and you can go 1 to 1 or whatever setting you chose.

Maybe you could compensate with a little higher intial timing setting, if you are after lower boost drivability/power?

Just an idea

If you are planning this for the SR-71 deal the upside is your timing widow is likely between 17 and 27 degree's total timing, I would think, so only a 10 degree window to deal with anyway.

https://www.google.com/search?q=adjustabe+air+pressure+poppet+valve&oq=adjustabe+air+pressure+poppet+valve&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIKCAEQABiABBiiBDIKCAIQABiiBBiJBTIKCAMQABiiBBiJBTIKCAQQABiABBiiBNIBCTM5NTM3ajBqN6gCALACAA&sourceid=chrome&ie=UTF-8

maverick172 wrote:why yu say timing window from 17to 27 you think with 20 # boost i only need to retard my timing to 17 max? or even 30 pounds boost ?

supervel45 wrote:Maybe some kind of pneumatic poppet valve between the BTM set at 4 PSI?

It's not exactly what you are after because when the poppet valve opens at 4 to 5 pounds of boost you will loose 4 to 5 degree's of timing instantly, if set at 1 to 1. It will delay it though, and you can go 1 to 1 or whatever setting you chose.

Maybe you could compensate with a little higher intial timing setting, if you are after lower boost drivability/power?

Just an idea

If you are planning this for the SR-71 deal the upside is your timing widow is likely between 17 and 27 degree's total timing, I would think, so only a 10 degree window to deal with anyway.

https://www.google.com/search?q=adjustabe+air+pressure+poppet+valve&oq=adjustabe+air+pressure+poppet+valve&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIKCAEQABiABBiiBDIKCAIQABiiBBiJBTIKCAMQABiiBBiJBTIKCAQQABiABBiiBNIBCTM5NTM3ajBqN6gCALACAA&sourceid=chrome&ie=UTF-8

I was using those numbers for a ballpark starting point with 10-12lbs. of boost in mind.

Is there anyway you can engine or chassis dyno your setup with the higher boost you mentioned?

When you say blow through I ass/ume it's carburetored?

ya so i got my car up and running just doing some final jet changes as i do short test hits.right now running just on the street doing 4-5pounds boost and running gulf 112 octane fuel . . car is crazy even with 4-5 pounds boost it spins the 15"wide tires at any speed 70 or even  80 mph . cannot wait to get it to track , but did not some numbers and i feel car is making around 900 hpbut i will be turning up the boost more at the track my plan is too probably go too around 8-9 pounds this season which i think will put me right at 8.5 seconds which is as fast as car is certified for . i am pulling 2 degree's timing right now per pound of boost and have my base timing at 26degree for saftey i am around 10-10.8 air fuel  WOT .but like i said i can only do very short pulls on highway (dont need a speeding ticket )
just thanking for the help as this has been a fun project getting this blow thru setup setup .

supervel45 wrote:

maverick172 wrote:why yu say timing window from 17to 27 you think with 20 # boost i only need to retard my timing to 17 max? or even 30 pounds boost ?

supervel45 wrote:Maybe some kind of pneumatic poppet valve between the BTM set at 4 PSI?

It's not exactly what you are after because when the poppet valve opens at 4 to 5 pounds of boost you will loose 4 to 5 degree's of timing instantly, if set at 1 to 1. It will delay it though, and you can go 1 to 1 or whatever setting you chose.

Maybe you could compensate with a little higher intial timing setting, if you are after lower boost drivability/power?

Just an idea

If you are planning this for the SR-71 deal the upside is your timing widow is likely between 17 and 27 degree's total timing, I would think, so only a 10 degree window to deal with anyway.

https://www.google.com/search?q=adjustabe+air+pressure+poppet+valve&oq=adjustabe+air+pressure+poppet+valve&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIKCAEQABiABBiiBDIKCAIQABiiBBiJBTIKCAMQABiiBBiJBTIKCAQQABiABBiiBNIBCTM5NTM3ajBqN6gCALACAA&sourceid=chrome&ie=UTF-8

I was using those numbers for a ballpark starting point with 10-12lbs. of boost in mind.

Is there anyway you can engine or chassis dyno your setup with the higher boost you mentioned?

When you say blow through I ass/ume it's carburetored?

You're welcome and looks good.
Those numbers seem pretty fat and retarded but, get it to the track, see how it runs and work into your tune from there.
Pull some spark plugs also and make sure you instruments (Timing Light and air fuel gauge) are not lying to you.
Be careful not to put it into the wall, sounds like a pretty hairy ride.

ya thanks .
ya i am working up too a leaner tune and yes with 112 or eventually i will run some 116 maybe around 12 pounds boost. but this short block i dont want to push it too much as it is still just h beam rods lunati steel crank and pistons are just the mahle 4032 pistons . so they are not really built for a real boosted engine i guess you could say i dont want to break the ring lands off the pistons .
ya so i used a pressure regulator to control the max psi that can go to the msd box . i think 10 degree of retarding the timing is all i need under full boost so basically i have the signal line regualted at max 10psi .ya i verified the timing retards under boost by simply hooking my air hose up the the msd box useing a pressure regulater and a timing light and can watch the timing light showing the timing pulling back how ever many pounds of pressure i put to the msd box to a max of 15 degree .ya my guess is on street i will just run t at like 26degree and pull 2 or 3 degrees per pound boost and max 4 pounds boost and should beable to run this on pump gas no problem for street driving than track tune under 112 or 116 will be eventually up too 28 degree and pull 1 degree per pound boost just wish i could figure a way of not allowing the msd to see any boost signal till 4 pounds and have it "trick the system to think it is only 1 pound and start pulling timing there . i probably will eventually get a holley dominator ecu and than i can have everything all in one . would be nice too have the boost controller as well vs just a manual boost control which is not really tunable . but still works great for the time being .ya am looking at plugs and so far i am def on the rich side just taking baby steps first time doing anything boosted and dont want to burn stuff up .

supervel45 wrote:You're welcome and looks good.
Those numbers seem pretty fat and retarded but, get it to the track, see how it runs and work into your tune from there.
Pull some spark plugs also and make sure you instruments (Timing Light and air fuel gauge) are not lying to you.
Be careful not to put it into the wall, sounds like a pretty hairy ride.

Sounds like the car is going to be real fast!!I take it the car is a Maverick if so can you post some pictures of the entire car?

Mark Miller wrote:Sounds like the car is going to be real fast!!I take it the car is a Maverick if so can you post  some pictures of the entire car?

i hope those pics went on.
ya i will only be pushing it to a max 1100 too maybe 1150hp with current short block . i have a a460 block which i will build with a callies crank oliver rods and some custom pistons but . just was not in budget for now

Thanks for the Pictures that's a Bad Ass Looking Car and looks good with the Big Meats on the back,is that Grabber Blue and what size are those Rear Tires?

honestly i am unsure on colour i would say yes grabber blue i did not paint the car . 33x19.5 15" is the tire size mickey tompson

Mark Miller wrote:Thanks for the Pictures that's a Bad Ass Looking Car and looks good with the Big Meats on the back,is that Grabber Blue and what size are those Rear Tires?

man your car is nuts! stock looking body,big tire and twins on a bbf.love it! when you go to track i would not turn it up untill you can get it to hook!

What size and type of turbos are you using?

Mark Miller wrote:Thanks for the Pictures that's a Bad Ass Looking Car and looks good with the Big Meats on the back,is that Grabber Blue and what size are those Rear Tires?

the rear tires are 19.5 wide 33 tall 15" rim .
and thanks

BBFTorino wrote:What size and type of turbos are you using?

they are 76mm on the inlet side and 88mm on the exhaust side . they spool almost instantly . but i am only running 4 pounds boost right now . just working on the transmission now . blew it up last weekend took out rear thrust washer and has a tci valve body in it which is a pos . just working on getting a frank merkle valve body for it now . and going to follow his directions on the full rebuild as well. by the end of the season i iwll be pushing 20# boost at some point in time just too see what it can do .car is only cert too 8.5 so i know if i leave it till end of season i will push but i dont want to get kicked from track either plus i want the engine to live for the season .