Like a pseudo tunnel ram.  Use four!

https://help.summitracing.com/app/answers/detail/a_id/5266/~/what-is-a-tunnel-ram%3F

20 hours ago, siteunseen said:

Double stack carb spacers? Never heard that but I'm no racer.

2 x these with longer bolts will add power? With a mechanical pump or would you need the electric like you have?

 

Well it is more complicated that simply adding a couple of spacers and longer studs.

The extra 12 or 14 millimeters the added spacer give is only part of the whole package. As I mentioned, the entire intake and exhaust stream was included in the flow bench testing, before and after the work. Port matching, smoothing everything along the way, work done around the valve guide bosses, three angle valve seat cutting, etc.

Also note the short exhaust system after the exhaust manifold. There is a relationship between the length of the intake runners and the exhaust, including the headpipes and muffler. The rules require the exhaust exits aft of the steering wheel hub, and meets the maximum decibel limits. I used the largest primary pipes, joined at the elbow just before it exits from under the car, and the muffler is a Lowbak used in circle track racing. Looks like a glasspack, but it isn't. A 3/4" length of tubing runs down the middle, wrapped with a piece of flat stock wrapped in a spiral around it, inserted into the larger tubing, welded in, and then the ends are swedged down to create what looks like a glasspack. There is no fiberglass packing in the muffler. It works very well, and my car never even came close to the decibel limits.

So, yes, it does add some power, and it is measurable on a flowbench. The carbs have had extensive work done too, to increase and enhance airflow through them, resulting in more fuel being drawn from the float chambers.

I also cheat the cam lift some by running tighter valve lash, which gives another couple of thousandths of an inch of valve lift, and effectively more duration.

A comprehensive package that results in more power output.

 

Oh, and I don;t run a mechanical fuel pump. I have never been a fan of them. When the diaphragm fails, fuel gets dumped into the crankcase, diluting the engine oil, which is not a good thing.

Edited December 22, 20204 yr by Racer X

So I assume the OE airbox wouldn't be viable?

Hell it's a pain to get it off there now with the one insulator.

Thank you Racer X. I love learning stuff. Maybe I can figure out something useful from your info.

7 minutes ago, siteunseen said:

So I assume the OE airbox wouldn't be viable?

Hell it's a pain to get it off there now with the one insulator.

Thank you Racer X. I love learning stuff. Maybe I can figure out something useful from your info.

I removed the velocity stacks from the airbox and mounted them to the carbs, and use a pair of Uni foam motorcycle air filter socks. No trouble fussing with a bulky airbox.

so @AK260 did you figure out fuel pump you are going to do with?

What about this NISMO one?  Any thoughts, opinions, or experiences with these?

 

https://www.ebay.com/itm/660122143-NISMO-High-Flow-Volume-Fuel-Pump-Electromagnetic-Piston-Type/133371205206?fbclid=IwAR0s4RwbojHnmGp909LiAy0DsYpQ1Uf2GGgz6GwwNcQZj0h-MCvJy-0O7YQ

Bump...

Looking for input on the above mentioned NISMO electronic fuel pump please.

so [mention=32052]AK260[/mention] did you figure out fuel pump you are going to do with?

Hey big boy, apologies for the delayed response, I’ve been off planet for a while, but now that I’m back on earth ...

I didn’t decide in the end but I am very tempted by the NISMO pump and a fuel regulator / filter like the one linked below which takes it down to 2.5-3.0 psi.

Having said all that, we went from torrential rain to prong for one day and I took the Z out for the first time in months and no longer had the issue. So I really have to investigate what in the tank is causing the issue.

@AK260 I gave up on the p4070, it was too loud and really annoying to drive with. Swapped it out with an Airtex 8016S,  this past Monday. Have a track event on Sunday so we will see how it holds. So far it’s much more quiet in the car, very faint at idle, but still can hear it when the car is off. Hopefully it works out for my use. Shame the p4070 was too loud, never had any issues with it.

[mention=32052]AK260[/mention] I gave up on the p4070, it was too loud and really annoying to drive with. Swapped it out with an Airtex 8016S,  this past Monday. Have a track event on Sunday so we will see how it holds. So far it’s much more quiet in the car, very faint at idle, but still can hear it when the car is off. Hopefully it works out for my use. Shame the p4070 was too loud, never had any issues with it.

Sorry to hear that dude! Good luck with the new one!

I haven’t yet heard a totally silent one on any classic car but then I don’t have any real experience of them other than being an observer ;)

Looks like a nice pump.  Everything is "stock", and it comes with fittings, straps and insulation.  4.5 psi at 30 gph.

https://www.summitracing.com/parts/atx-e8016s