Compound boost - blower + turbos

[ayousef]

Originally Posted by jessrayo

Thanks for the encouragement Robert, unless I try to get compound boost before October, my car will only have minor tweaks. I know my car can do it with my current power level... it just need everything to come together....

how about this, instead of going compound boost and adding a lot of complexity and a lot of weight, switch the PD blower to an F1X and nice intake manifold...

[mylftft]

I was there when Robert went 183 in the half, I jumped in the air & yelled YES while swinging my fist in the air, I knew he was about to crush the record, then the chute came out & I knew the car was hurt, sucked to see that chute come out early.
Jess your car will do it at the power level your at, your making more power than when my car did it, get that throttle body issue worked out & your good to go. I know you know that but I want to see my ADM brother be the only other ZL1 to be in the 200 mph club.
If I don't bring my car to the event I will still come to watch you guys go for it & help anyway I can, even if its pushing the car to the line to keep the heat out of it.
If I decide to invest in a set of 19" wheels & Hoosiers or Toyo's I might turn the boost up & see if I can go faster & extend the ZL1 time. I can't picture going any faster on the Good Years due to traction issues we fought with the 1st time.

[jessrayo]

Originally Posted by ayousef

how about this, instead of going compound boost and adding a lot of complexity and a lot of weight, switch the PD blower to an F1X and nice intake manifold...

In my opinion the certrifical's have the exact same power band as the turbos with little torque on the bottom and a very big head of steam at the top. I would rather go straight turbos than swap to a centri because I think they work more efficiently. I do not want to lose the mountain of torque I currently have when I'm road racing. Straight centri's or turbos are out on this car.

Originally Posted by mylftft

I was there when Robert went 183 in the half, I jumped in the air & yelled YES while swinging my fist in the air, I knew he was about to crush the record, then the chute came out & I knew the car was hurt, sucked to see that chute come out early.
Jess your car will do it at the power level your at, your making more power than when my car did it, get that throttle body issue worked out & your good to go. I know you know that but I want to see my ADM brother be the only other ZL1 to be in the 200 mph club.
If I don't bring my car to the event I will still come to watch you guys go for it & help anyway I can, even if its pushing the car to the line to keep the heat out of it.
If I decide to invest in a set of 19" wheels & Hoosiers or Toyo's I might turn the boost up & see if I can go faster & extend the ZL1 time. I can't picture going any faster on the Good Years due to traction issues we fought with the 1st time.

You need to come back and push the record with your car a little. If you go to 19"s the tires are much shorter and you may need another gear. I think you would do the best with the 20" toyo's on the stock rims.....much, much better traction than the goodyears and close to the same tire height. Plus if you don't come out there is a good chance I'm going to beat your record....I just can't see you standing for that....lol.

[SSE 4 2SS]

Originally Posted by ayousef

interesting so how heavy will your car be when its all said and done?

It's been right at 4600 lbs with me in the car, but it may be a bit lighter come October... I'm thinking about the chrom-moly tube for the cage... And we are going to remove some un-needed items... A/C for one... Extra airbags etc...

Originally Posted by jessrayo

In my opinion the certrifical's have the exact same power band as the turbos with little torque on the bottom and a very big head of steam at the top. I would rather go straight turbos than swap to a centri because I think they work more efficiently. I do not want to lose the mountain of torque I currently have when I'm road racing. Straight centri's or turbos are out on this car.
You need to come back and push the record with your car a little. If you go to 19"s the tires are much shorter and you may need another gear. I think you would do the best with the 20" toyo's on the stock rims.....much, much better traction than the goodyears and close to the same tire height. Plus if you don't come out there is a good chance I'm going to beat your record....I just can't see you standing for that....lol.

Hoosier has a new DOT road racing slick out... 315/xx/19 that is 28.9 inches tall... Same tire I'll be running... .4 inches taller than factory...

[jessrayo]

Originally Posted by SSE 4 2SS

It's been right at 4600 lbs with me in the car, but it may be a bit lighter come October... I'm thinking about the chrom-moly tube for the cage... And we are going to remove some un-needed items... A/C for one... Extra airbags etc...


Hoosier has a new DOT road racing slick out... 315/xx/19 that is 28.9 inches tall... Same tire I'll be running... .4 inches taller than factory...

That looks like a very good choice........its a 315/40/19, the 315/30/19 is only 26.1 almost 3 inches shorter and that used to be the only choice. The shorty is great for road racing if you want your car down on the pavement.....

I think if Josh got on those and could keep his foot in it he might see 210, Robert, I'm pretty sure you will have the Gen5 record..... I was wondering what tire you were using to give you those speeds on your gearing chart....lol. Thanks for the update.

[jessrayo]

Okay, back to the original topic, compound boost. I have been reading a bunch of technical crap in other forums and this is a hodgepodge of what I think I have figured out. I probably should have linked them and made more detailed notes but for the most part I was just reading. A lot of this is from forums where people just tried stuff and then explained what happened. Really don't know how good they were at troubleshooting. Here goes anyway.

1. When it comes to peak power, the turbocharger portion of every compound boost system could make more power all by itself because at some point near the top of the powerband the blower basically becomes a restriction.
2. Some people have measured boost pressure before and after the supercharger and found much more boost in front of the supercharger than after. A lot of this is attributed to the intercooler bricks used in the supercharger restricting flow.
3. In some supercharger systems the supercharger bypass can be manually overridden to help push more turbo boosted air at higher pressure into the engine without passing the intercooler brick restriction. (of course my LS9 blower routes all bypass air through the intercooler bricks)
4. Even in superchargers with a bypass that diverts around the brick, the supercharger bypass opening is always too small to handle the full volume of air produced by high flow/ high boost turbochargers.
5. The biggest key to the max potential power available seems to be the blower, you can have 35 pounds of boost in front of the blower and only 18 that can pass to the intake manifold. So bigger turbos doesn't necessarily mean more boost, just a bigger bottleneck.
6. The end result generally equates to approximately a 10-25% gain over the supercharger at it's maximum stand alone capability with less overall heat and much more weight and complexity.

After all of this I'm thinking someone needs to design a supercharger with a huge bypass valve for the sole purpose of allowing unlimited compound boost.

So.... for me this comes down to... would it be worthwhile to add all the turbo equipment and gain 80-200 whp while keeping all the torque I have now.... or do I sell the blower and install just the turbos.....or do I need to put on a 4L Kenney Bell blower....

Ayousef... I'll bet your 4.0 whipple would work pretty well....

[ayousef]

well Kennebells are shit, Whipples are awesome but its a lot of work to get a PD blower to flow all that air which is why I recommended an F1X, you will make craploads of power and enough torque everywhere, you could be easily making 400 more rwhp vs your current set-up!!

if I learned one thing its, the less complex the better.

Also, I don't understand how a blower bypass valve would help anything? Assume the bypass valve is open and can flow enough air, how will the air from the turbos get into the motor if it keeps on escaping through the bypass valve, doesn't make sense UNLESS you can tap into the lower intake manifold of the blower and boost that area using the turbos, then again this itself has its own issues. This is what im talking about:



If for some odd reason you don't want to go the centrifugal route (which is the best in your case) then a plain twin turbo setup would be the best. Get some proper turbos with dual scroll housings and install quick spool valves on each one. This way you have half of the turbine housing shut until say 10psi so it spools up really quick, then the valve opens up and you get the full high-rpm potential of a big turbine housing turbo. You can also use a PROPER boost controller to keep the wastegates fully shut until you hit a pre-defined boost number instead of having them creep open as the turbos build boost.

I really think the centri is your best option minus the fact that you will essentially have a "hot air intake" with the direction the centrifugals face on Gen 5 platforms.

Now if you still wanna experiment with compound boost goto ls1tech into the advanced tech forum and look for the granatelli compound boost thread.

[ayousef]

also I just read your response above on not wanting a centri or turbo, not sure how I missed it. You will still have craploads of torque with an F1X, unless you're road racing below 3000rpms lol.

[Unreal]

Bypass valve just bypasses the blower and goes right into the intake/intercooler of the blower.

[jessrayo]

Originally Posted by ayousef

well Kennebells are shit, Whipples are awesome but its a lot of work to get a PD blower to flow all that air which is why I recommended an F1X, you will make craploads of power and enough torque everywhere, you could be easily making 400 more rwhp vs your current set-up!!

if I learned one thing its, the less complex the better.

Also, I don't understand how a blower bypass valve would help anything? Assume the bypass valve is open and can flow enough air, how will the air from the turbos get into the motor if it keeps on escaping through the bypass valve, doesn't make sense UNLESS you can tap into the lower intake manifold of the blower and boost that area using the turbos, then again this itself has its own issues. This is what im talking about:



If for some odd reason you don't want to go the centrifugal route (which is the best in your case) then a plain twin turbo setup would be the best. Get some proper turbos with dual scroll housings and install quick spool valves on each one. This way you have half of the turbine housing shut until say 10psi so it spools up really quick, then the valve opens up and you get the full high-rpm potential of a big turbine housing turbo. You can also use a PROPER boost controller to keep the wastegates fully shut until you hit a pre-defined boost number instead of having them creep open as the turbos build boost.

I really think the centri is your best option minus the fact that you will essentially have a "hot air intake" with the direction the centrifugals face on Gen 5 platforms.

Now if you still wanna experiment with compound boost goto ls1tech into the advanced tech forum and look for the granatelli compound boost thread.

Okay, first if you look at the granatelli system, I will link a picture if I can, the turbos feed unto the blower. So air in front of the throttle body is pressureized by turbos and then that pressurized air enters the supercharger. The bypass in these systems open the "pressurized area of the manifold under the supercharger" to the intake tube. In all the systems I have seen before your pic the supercharger intake tube is pressureized by the turbos so opening the bypass will let turbo pressurized air go under the supercharger rotors. I've never seen anything like that banks monstrosity....lol.

[SSE 4 2SS]

Originally Posted by jessrayo

Okay, first if you look at the granatelli system, I will link a picture if I can, the turbos feed unto the blower. So air in front of the throttle body is pressureized by turbos and then that pressurized air enters the supercharger. The bypass in these systems open the "pressurized area of the manifold under the supercharger" to the intake tube. In all the systems I have seen before your pic the supercharger intake tube is pressureized by the turbos so opening the bypass will let turbo pressurized air go under the supercharger rotors. I've never seen anything like that banks monstrosity....lol.

My only issue with this is I wouldn't buy a life preserver from Granatelli if I was tied to the screw on the Titanic...


To my knowledge that was a show mock up that has never progressed any further... I actually pulled the pictured turbos off that very motor and put them in on my car in Phoenix after my first set of turbos blew up in less than a week... And my only chance to get back on the road was those two... He made me buy them as well.

He "offered" to ship my original two back to precision for a rebuild... Upgrade... They were mine, bought and paid for.. He wanted something to put on his display motor... So I agreed... He then had them shipped back to him rather than allowing me to pay the upgrade cost and refunded me less than half what I paid him for the two new ones... He is a thief and worthless person in my book...

Off my soapbox... Sorry...

[jessrayo]

Originally Posted by SSE 4 2SS

My only issue with this is I wouldn't buy a life preserver from Granatelli if I was tied to the screw on the Titanic...


To my knowledge that was a show mock up that has never progressed any further... I actually pulled the pictured turbos off that very motor and put them in on my car in Phoenix after my first set of turbos blew up in less than a week... And my only chance to get back on the road was those two... He made me buy them as well.

He "offered" to ship my original two back to precision for a rebuild... Upgrade... They were mine, bought and paid for.. He wanted something to put on his display motor... So I agreed... He then had them shipped back to him rather than allowing me to pay the upgrade cost and refunded me less than half what I paid him for the two new ones... He is a thief and worthless person in my book...

Off my soapbox... Sorry...

I just put up their pics because they seem to be well known as far as this concept goes and ayousef mentioned them. I must admit the concept sure looks simple and workable in their little mock-up.

I think my current LS9 blower is probably the worst blower to use for this concept because the intercooler bricks cannot be bypassed and they are realitively small and restrictive. I like the idea of cooling all of the intake charge through the supercharger bricks but the LS9 bricks have a pretty significant pressure drop across the brick when you get above 12 pounds of boost. I don't think I could push more than 17 pounds through my current blower. I have made some inquiries and it seems that no one has a Heartbeat available right now and Magnuson seems to be pretty well sold out. I think I might be able to get 20 pounds of cooled charge through those Heartbeat bricks....

[Trackman]

[smokum]

+1