1" Spacers

[SIXBANGR]

I have one, $75 shipped, has been engraved on the sides.

 

["Reaper"]

1" ?
Got a pic?

 

[SIXBANGR]

yes 1"

 

[1KWIKSIX]

I run a champion spacer with a Hemco and of everything I have tried I believe that works the best. I blocked off the vacuum block with a plate and drilled / tapped the spacer for the vacuum lines. Much cleaner look IMO FYI we have spacers in the building ready to ship

I've got a couple of Hemco Plenums in my garage & have been thinking about installing one of them. Both are stock appearing in 58mm & a 62mm size.
Presently running a stock throttle body (bored out to 62mm) & hogged out plenum (by Steve Munroe) & RJC's plenum air distribution plate.

Mike, If you don't mind me asking, have a few questions that I'm hoping you can answer for me.....
1) what thickness plenum spacer do you run?
2) What size Hemco Plenum...ie 58mm , 62mm, 65mm, 70mm ?
3) is your Hemco Plenum the Stock Appearing style or Hemco's Race Plenum?

Thanks,
dave

 

[tonysmach]

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[TTipe]

I run a champion spacer with a Hemco and of everything I have tried I believe that works the best. I blocked off the vacuum block with a plate and drilled / tapped the spacer for the vacuum lines. Much cleaner look IMO FYI we have spacers in the building ready to ship

What data points or table values do you have which are indicative of such great air balance ?

 

[TTipe]

My car came with a 1" spacer and I was going to try a PP, but have no need as my engine runs like ten good men without one and I run 22/23 lbs. of boost with the alky turned off and 11.2 on the W/B with no KR so I think all cylinders are close enough to not cause a lean condition and KR.

My feelings are if it ain't broke don't fix it, that's when real problems start to rear their ugly heads. When you throw stuff at it just for the sake of trying it and then wonder why the car is getting slower and you realize you could have better spent your money elsewhere.

When running at 22/23 psi with no alky what fuel octane did you have?

 

[robzombie]

I run 93 octane. I also have to say that I can't get away with that when the air temps are in the high 80"s and above.

I start to get about 2/4* of knock in the 90* temp range.

I'm guessing that the 10% ethanol in the fuel helps contribute to that but mostly it's in the tune for sure.

 

[TTipe]

I run 93 octane. I also have to say that I can't get away with that when the air temps are in the high 80"s and above.

I start to get about 2/4* of knock in the 90* temp range.

I'm guessing that the 10% ethanol in the fuel helps contribute to that but mostly it's in the tune for sure.

A legitimate octane additive like maybe 1 full point (to 94 from 93) will get you through the heat.

 

[robzombie]

In theory the octane ratings are supposedly a minimum rating and could be higher.

I buy my fuel at the same station every time just for that reason as my car runs best when I fill up there.

If knock becomes a concern I just turn the alky on and set it to 3 and have no issues at all.

When I turn it up to 26/27 lbs. I turn the alky up accordingly.

 

[earlbrown]

A "point" on those worthless 'octane boosters' are .1 octane. It would take 10 points to go from 93 to 94.

 

[coach]

A little design info about the Hemco plenums. There is no difference between the race and the stock appearing. If you cut them in half...the air flow pattern is the same. They just changed the outside to appear stock.
Next is the air flow design. It does not require a power plate, nor a 1" spacer. If you set it next to a stock plenum...you will see that it was designed about 1" taller then a stock unit. To add another inch of empty plenum volume would actually throw off the air distribution...as it was designed to work. My new stroker runs a 70mm that's been polished and opened up to 72mm.
I personally know 2 cars running mid 9's that run 62mm Hemcos w/ NO spacer. Both are near 700 rwhp.

 

[Mike Licht]

I've got a couple of Hemco Plenums in my garage & have been thinking about installing one of them. Both are stock appearing in 58mm & a 62mm size.
Presently running a stock throttle body (bored out to 62mm) & hogged out plenum (by Steve Munroe) & RJC's plenum air distribution plate.

Mike, If you don't mind me asking, have a few questions that I'm hoping you can answer for me.....
1) what thickness plenum spacer do you run?
2) What size Hemco Plenum...ie 58mm , 62mm, 65mm, 70mm ?
3) is your Hemco Plenum the Stock Appearing style or Hemco's Race Plenum?

Thanks,
dave

the Hemco is stock appearing , both are 62MM it is one of the throttle bodies we bored out many years ago, I use a 1" spacer

 

[Mike Licht]

What data points or table values do you have which are indicative of such great air balance ?

We did extensive flow testing on flow bench and on car with different combos, with and without plates, the hemco / spacer worked best. Most interesting the old phoenlic spacers we sold when the cars were new that had an opening like a Hemco were pretty good too

 

[TTipe]

Thank you for great feedback.

 

[TTipe]

A little design info about the Hemco plenums. There is no difference between the race and the stock appearing. If you cut them in half...the air flow pattern is the same. They just changed the outside to appear stock.
Next is the air flow design. It does not require a power plate, nor a 1" spacer. If you set it next to a stock plenum...you will see that it was designed about 1" taller then a stock unit. To add another inch of empty plenum volume would actually throw off the air distribution...as it was designed to work. My new stroker runs a 70mm that's been polished and opened up to 72mm.
I personally know 2 cars running mid 9's that run 62mm Hemcos w/ NO spacer. Both are near 700 rwhp.
View attachment 223496

I assume that your Hemco was cleaned up internally after the "over bore" but the contour into the lower intake manifold was not touched.

 

[TTipe]

A little design info about the Hemco plenums. There is no difference between the race and the stock appearing. If you cut them in half...the air flow pattern is the same. They just changed the outside to appear stock.
Next is the air flow design. It does not require a power plate, nor a 1" spacer. If you set it next to a stock plenum...you will see that it was designed about 1" taller then a stock unit. To add another inch of empty plenum volume would actually throw off the air distribution...as it was designed to work. My new stroker runs a 70mm that's been polished and opened up to 72mm.
I personally know 2 cars running mid 9's that run 62mm Hemcos w/ NO spacer. Both are near 700 rwhp.
View attachment 223496

Just one more question. Do you have a ported lower intake manifold with the EGR chimney removed? If so does it make sense that the removal of the EGR chimney might improve the flow numbers on cylinders 1 & 2. The flow numbers that I have seen from the Hemco seem to indicate a lot of flow to the middle cylinders, a little less 5 & 6 and the least to 1 & 2. Does this concur with your findings?

 

[87turbot-type]

Thanks Coach. I was wondering if the plenum was higher that the stock unit. I have a hemco waiting to go on but have not compared it to the stock one as it is still on the car. I need the height myself to make the intercooler pipes fit better (Cottons front mount). I know Brian has a cottons front and a hemco and doesn't look like he has a spacer so I am hoping I will be good to go.

Thanks Brandon.

 

[coach]

I assume that your Hemco was cleaned up internally after the "over bore" but the contour into the lower intake manifold was not touched.

Yes. It was polished by Dave Mills. He just removed the rough casting on the inside.

 

[coach]

Thanks Coach. I was wondering if the plenum was higher that the stock unit. I have a hemco waiting to go on but have not compared it to the stock one as it is still on the car. I need the height myself to make the intercooler pipes fit better (Cottons front mount). I know Brian has a cottons front and a hemco and doesn't look like he has a spacer so I am hoping I will be good to go.

Thanks Brandon.

It's higher. You can see in the pic I posted in my first post. It almost has a 1" rise built into it. Brian does not run a spacer. His 4" pipe fits and he also runs a Cottons front mount