Installed Stinker's 7" Lower Pully Today...

[blackviper]

Prof, did you lower your compression ratio? I'm thinking the majority of the lost boost on all these builds is mostly due to compression ratios. Yes, ported heads will affect the overall number but it should be no more than 2 to 4 pounds.

By the way, these blowers are good for 18,000 rpms. Stinker mentioned the blower will run out of air. I'd rather say, it will become inefficient because of the heat build up without an intercooler.

 

[Prof]

I did nothing to the compression ratio.

But maybe I overlooked an opportunity...to be honest I did not even consider the compression options...

 

[Yellow venom]

Prof, did you lower your compression ratio? I'm thinking the majority of the lost boost on all these builds is mostly due to compression ratios. Yes, ported heads will affect the overall number but it should be no more than 2 to 4 pounds.

By the way, these blowers are good for 18,000 rpms. Stinker mentioned the blower will run out of air. I'd rather say, it will become inefficient because of the heat build up without an intercooler.

Speaking of "compression ratio" I'm doing a build right now,forged pistons,rods and some head work,not going super crazy on the porting and polishing,light massage on intake side mostly working on the exhaust side and a little work in the combustion chamber,I am putting a ROE on it also. And I was woundering what CR to run? My builder recommends between 9:0:1 to 9:5:1 What do you figure and whats the differences? (pros and cons)
I am going to run the stock ROE pully to start but eventually going to run Stinkers 7" and a 10# ROE, with the the possabilty of maybe spraying 150shot max!

 

[TNVIPER]

My CR is 9.2 (stock is 9.6).....I did not lower it based on any direct facts based on a Viper engine with a Roe....rather just the fact that engines designed with blowers have low CR...and at the time could not find a piston that would produce a CR between 9.2 and 10.X (my engine is forged with GM type rods & pistons)....

 

[Manic]

I agree the calculation is difficult due to the differences between engines.

When Sean tuned my engine in the fall with the 10 lb pulley, he had difficulty getting the boost to where he thought it should be. Then he asked if I had any head work done, and I said no...but that my builder had done a little cleaning up and port matching last spring...and his eyes popped! Evidently the "clean-up" head work was some pretty extensive clean up and really increased the flow to the point that boost would not go past about 8 lbs due to increased flow...my error in not telling him...but very educational.

Roy,

With the clean up of the heads, does that mean you would be allowed to run a larger pulley if available, or have you reached the maximum flow for the Roe?

Wil

 

[Prof]

I don't think we have even approached the end point for the compressor in the Roe...there is a lot of potential there and BlackViper is beginning to explore those outer limits...he will be the prototype big Roe blower...

If someone really wants to see what one will do they will do all the flow work (intake and exhaust) and push with a 12 lb blower pulley and a seven inch lower...

14 or 15 lbs of boost on a clean flowing engine may be a beast to behold!

 

[Manic]

Sorry Roy, I forgot that Sean is working on a revised intake for the ROE SC in a different thread. Have you heard anything more about it?

Wil

 

[blackviper]

Speaking of "compression ratio" I'm doing a build right now,forged pistons,rods and some head work,not going super crazy on the porting and polishing,light massage on intake side mostly working on the exhaust side and a little work in the combustion chamber,I am putting a ROE on it also. And I was woundering what CR to run? My builder recommends between 9:0:1 to 9:5:1 What do you figure and whats the differences? (pros and cons)
I am going to run the stock ROE pully to start but eventually going to run Stinkers 7" and a 10# ROE, with the the possabilty of maybe spraying 150shot max!

Stay as close to 9.5 to 1 compression.

 

[Prof]

Sorry Roy, I forgot that Sean is working on a revised intake for the ROE SC in a different thread. Have you heard anything more about it?

Wil

Last I heard from him was that it was not on the top of his todo list...there is a lot of thinking and engineering to do before he jumps...and then there is the marketing reality...what good would it do to spend 100k in development and end up selling one for 100K or four for 25k...I don't think the return on the investment is making the grade.

 

[Yellow venom]

Stay as close to 9.5 to 1 compression.

OK, I was talking with my builder and he would like to run between 9:0:1 and 9:5:1,meeting with him on Sat to go over everything that he is doing,its gonna be good!:burnout:

 

[Bone]

Roy,

With the clean up of the heads, does that mean you would be allowed to run a larger pulley if available, or have you reached the maximum flow for the Roe?

Wil

You still have to port the tray and manifold to the heads, along with the heads.

The tray you have to be careful with. That is what Sean used to keep the A/F ratio even across the cylinders.

 

[Prof]

I totally agree with Bone.

There was a lot of magic and engineering in the tray. It is one of the complicating issues in the development of an intercooler that might be positioned there.

 

[Yellow venom]

What ever happen with the tread on porting the tray and enlarging the slots?

 

[Bone]

What ever happen with the tread on porting the tray and enlarging the slots?

I posted awhile ago on that, maybe it got deleted?

 

[blackviper]

If you space the intercooler 1/2 inch from the S/C plate, the blower will fill that area across the entire length of the intercooler before it travels through it. In theory, the air should find the path of least resistance first. This should allow the air to be distributed evenly to all the cylinders. The key is having the core run the length of the manifold. I will also be installing widebands on the headers for the front, middle and back cylinders in case we need to tune by cylinder.

 

[TNVIPER]

BTW..if you go with this pulley and have the Roe SC with the STANDARD Roe 5.6LB pulley (PSI with 7" pulley will be 11LB+) you will need this belt...

..

Encountered a small problem witn the belt...dang thing evidently jumped a pulley and shredded into a hundred pieces...:argh: ..........we thought the belt was tight enough but after replacing the shredded one we determined it was not.

I have a slighly larger idler pulley that I had installed with the smaller 10LB pulley on the Roe before the 7" crank pulley (I now have the original Roe 5.6LB pulley installed). I replaced the OEM idler the larger idler pulley and the belt now seems tight enough..

Idler pulley came from NAPA...Gates 38042 Backside Idler Pulley...

 

[Prof]

Is there a way to accurately measure before purchasing pulley belts?

 

[DevilDawg3097]

Is there a way to accurately measure before purchasing pulley belts?

you can use a piece of string as a guide,it will get you pretty darn close