Boost Changes Coming
Thread Starter
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
Boost Changes Coming
Well many of you have followed along as I went from the ATI FMIC to the custom Spearco horizontal flow. Back when I made this change, I was running the other head unit, but picked up 2 psi.
Following the change to the D1R, I then built and modified a 5.5" thick core that totally "wraps the radiator and converted to verticle flow. I have been slowly working on this, as time allows. But not yet run.
Well in the interim, last winter I did a test bypassing the Spearco core (still with ducting intact). With the old MRII and 58MM TB, I typically saw ~12 psi at 6200, and 6.5 psi at 4000. During the test, I bounced 9 psi at 4000 before I blew the ducting off the bypass pipe. But man that thing really revved quickly!
Well it was too hot to run without the IC in the Spring and Summer, and you may also recall that at the end of a full pull, I am 228°F IAT.
Well, I finally removed the Spearco and all the associated piping and am making an "S" to route directly from the blower discharge to the TB inlet. I will incorporate the BO valve and twin xxOH injection nozzles.
My most recent pass on the dyno only had 10.5 psi due to the new intake, MB, and the change in head flow. With the loss of the IC and ducting, I have lost (8) 90° bends, (3) 45° bends, and ~9' od ducting. This will be replaced with ~1'1" of gradually increasing area going from 3.25" to 4.25" diameter constantly sloping "S" curve.
Anyone care to guess how much boost I was leaving on the table? I am hoping to see 5 psi plus increase. Possible?
Pics should be posted shortly.
Aaron
Following the change to the D1R, I then built and modified a 5.5" thick core that totally "wraps the radiator and converted to verticle flow. I have been slowly working on this, as time allows. But not yet run.
Well in the interim, last winter I did a test bypassing the Spearco core (still with ducting intact). With the old MRII and 58MM TB, I typically saw ~12 psi at 6200, and 6.5 psi at 4000. During the test, I bounced 9 psi at 4000 before I blew the ducting off the bypass pipe. But man that thing really revved quickly!
Well it was too hot to run without the IC in the Spring and Summer, and you may also recall that at the end of a full pull, I am 228°F IAT.
Well, I finally removed the Spearco and all the associated piping and am making an "S" to route directly from the blower discharge to the TB inlet. I will incorporate the BO valve and twin xxOH injection nozzles.
My most recent pass on the dyno only had 10.5 psi due to the new intake, MB, and the change in head flow. With the loss of the IC and ducting, I have lost (8) 90° bends, (3) 45° bends, and ~9' od ducting. This will be replaced with ~1'1" of gradually increasing area going from 3.25" to 4.25" diameter constantly sloping "S" curve.
Anyone care to guess how much boost I was leaving on the table? I am hoping to see 5 psi plus increase. Possible?
Pics should be posted shortly.
Aaron
Drifting
Joined: Dec 2001
Posts: 1,313
Likes: 1
From: providence ut
Originally Posted by AKS Racing
Well many of you have followed along as I went from the ATI FMIC to the custom Spearco horizontal flow. Back when I made this change, I was running the other head unit, but picked up 2 psi.
Following the change to the D1R, I then built and modified a 5.5" thick core that totally "wraps the radiator and converted to verticle flow. I have been slowly working on this, as time allows. But not yet run.
Well in the interim, last winter I did a test bypassing the Spearco core (still with ducting intact). With the old MRII and 58MM TB, I typically saw ~12 psi at 6200, and 6.5 psi at 4000. During the test, I bounced 9 psi at 4000 before I blew the ducting off the bypass pipe. But man that thing really revved quickly!
Well it was too hot to run without the IC in the Spring and Summer, and you may also recall that at the end of a full pull, I am 228°F IAT.
Well, I finally removed the Spearco and all the associated piping and am making an "S" to route directly from the blower discharge to the TB inlet. I will incorporate the BO valve and twin xxOH injection nozzles.
My most recent pass on the dyno only had 10.5 psi due to the new intake, MB, and the change in head flow. With the loss of the IC and ducting, I have lost (8) 90° bends, (3) 45° bends, and ~9' od ducting. This will be replaced with ~1'1" of gradually increasing area going from 3.25" to 4.25" diameter constantly sloping "S" curve.
Anyone care to guess how much boost I was leaving on the table? I am hoping to see 5 psi plus increase. Possible?
Pics should be posted shortly.
Aaron
Following the change to the D1R, I then built and modified a 5.5" thick core that totally "wraps the radiator and converted to verticle flow. I have been slowly working on this, as time allows. But not yet run.
Well in the interim, last winter I did a test bypassing the Spearco core (still with ducting intact). With the old MRII and 58MM TB, I typically saw ~12 psi at 6200, and 6.5 psi at 4000. During the test, I bounced 9 psi at 4000 before I blew the ducting off the bypass pipe. But man that thing really revved quickly!
Well it was too hot to run without the IC in the Spring and Summer, and you may also recall that at the end of a full pull, I am 228°F IAT.
Well, I finally removed the Spearco and all the associated piping and am making an "S" to route directly from the blower discharge to the TB inlet. I will incorporate the BO valve and twin xxOH injection nozzles.
My most recent pass on the dyno only had 10.5 psi due to the new intake, MB, and the change in head flow. With the loss of the IC and ducting, I have lost (8) 90° bends, (3) 45° bends, and ~9' od ducting. This will be replaced with ~1'1" of gradually increasing area going from 3.25" to 4.25" diameter constantly sloping "S" curve.
Anyone care to guess how much boost I was leaving on the table? I am hoping to see 5 psi plus increase. Possible?
Pics should be posted shortly.
Aaron
Thread Starter
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
I drove it today without the ducting. The blower overpowers the sound of the engine at 1800 RPM. I have no doubt that I will get boost sooner, but I sure hope that I pick up a bit on top. Everyone looks at you as you drive (different sort of whistling sound).
This is the largest blower (most CFM) that I am aware that anyone has installed on a small block C4. I think it is seriously restricted with the ducting for the Spearco IC.
So you are betting 4 psi (that would total 14.5psi). I am hoping for more.
The base and both walls as well as the 3.25" round and 4.5" oval end of the ducting are complete. I am going back to a single BOV (ATI ProRace). I hope to have it finished tomorrow, but have not purchased the xxOH package (still looking).
Aaron
This is the largest blower (most CFM) that I am aware that anyone has installed on a small block C4. I think it is seriously restricted with the ducting for the Spearco IC.
So you are betting 4 psi (that would total 14.5psi). I am hoping for more.
The base and both walls as well as the 3.25" round and 4.5" oval end of the ducting are complete. I am going back to a single BOV (ATI ProRace). I hope to have it finished tomorrow, but have not purchased the xxOH package (still looking).
Aaron
Thread Starter
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
Steven,
I am probably one of the few people who insist that the car be driveable 99% of the time. The car is not down currently. It has been up throughout the total ordeal. Even had to pull the inlet off the TB and the discharge off the blower to get the measurements for the new ducting. I drove it last weekend, and it is still as nasty as ever.
The duct is complete, I just need to do some final fit / finish work, drill and tap for the bypass, and install the xxOH injection. At that time, I will yank all of the remnants of the IC off and put all of the factory radiator ducting along with the secondary fan back in the car. Maybe we will see even better cooling.
BTW, have you seen my new yellow convertible. I have taken it to church a few times. No serious mods yet, but when I do, I do not think I will go SC'ed.
You should drop by the house sometime, and don't be a stranger. You know you are still a vette guy at heart.
Aaron
I am probably one of the few people who insist that the car be driveable 99% of the time. The car is not down currently. It has been up throughout the total ordeal. Even had to pull the inlet off the TB and the discharge off the blower to get the measurements for the new ducting. I drove it last weekend, and it is still as nasty as ever.
The duct is complete, I just need to do some final fit / finish work, drill and tap for the bypass, and install the xxOH injection. At that time, I will yank all of the remnants of the IC off and put all of the factory radiator ducting along with the secondary fan back in the car. Maybe we will see even better cooling.
BTW, have you seen my new yellow convertible. I have taken it to church a few times. No serious mods yet, but when I do, I do not think I will go SC'ed.
You should drop by the house sometime, and don't be a stranger. You know you are still a vette guy at heart.
Aaron
Thread Starter
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
Steven,
And I forgot to mention that we have nearly completed the build on the 4th Gen white SS for Travis. The SS was free, but many of the parts have been a bit more expensive than originally planned.
Aaron
And I forgot to mention that we have nearly completed the build on the 4th Gen white SS for Travis. The SS was free, but many of the parts have been a bit more expensive than originally planned.
Aaron
