Who's run a tunnel ram and propane?

Propane, Butane, LPG, GPL, C3H8, C4H10
User avatar
kikkegek
Posts: 371
Joined: Thu Nov 17, 2011 2:12 pm
Location: Netherlands, The Hague

Re: Who's run a tunnel ram and propane?

Post by kikkegek » Tue Oct 06, 2015 2:46 am

I am currently running a Edelbrock Torker II on my freshly rebuild SBC350 with a IMPCO425 on top.

Runs sweet. power through the whole range and no lag.

Image

I am in the proces of adding a 2 inch phenolic open spacer to see if it will add any moer torque to the setup.

Image
daily: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.1 end gears - IMPCO425 mixer - IMPCO model E vaporizer
project: 1977 GMC C15 Suburban - 454 big block - TH400 - gasoline
sold: 1986 Chevrolet Suburban K20 Silverado


gottago
Posts: 200
Joined: Thu May 24, 2012 7:39 pm
Location: British Columbia Canada

Re: Who's run a tunnel ram and propane?

Post by gottago » Wed Oct 07, 2015 8:37 pm

Lousy pics but the one I have is an efi manifold, just modified a bit. Was originally going to be dual fuel, gasoline through injectors, propane through two side draft mixers. Haven't run it enough to see all it is capable of yet. Currently has two gra mixers but have been making adapters to try other mixers on it as well.

Its a tunnel ram base, short runners with a common top plenum. So can run progressive linkage without any difficulty. Maybe not really a true tunnel ram, guess that's why they call it a mini ram.
Attachments
100_3705 small.jpg
100_3708 small.jpg
100_3706 small.jpg

User avatar
kikkegek
Posts: 371
Joined: Thu Nov 17, 2011 2:12 pm
Location: Netherlands, The Hague

Re: Who's run a tunnel ram and propane?

Post by kikkegek » Thu Oct 08, 2015 1:39 am

Looks cool. Did you weld the aluminum yourself?

I have been thinking about putting on a tpi intake and adding the 425impco on the front. But can't weld aluminum yet.

They are supposed to be good for bottom end torque....and look cool I think

Image
Last edited by kikkegek on Thu Oct 08, 2015 6:14 am, edited 1 time in total.
daily: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.1 end gears - IMPCO425 mixer - IMPCO model E vaporizer
project: 1977 GMC C15 Suburban - 454 big block - TH400 - gasoline
sold: 1986 Chevrolet Suburban K20 Silverado

storm
Posts: 565
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: Who's run a tunnel ram and propane?

Post by storm » Thu Oct 08, 2015 4:07 am

That is similar to GRA's Tornado setup which is a knock off of the external look of Holden's Group A EFI manifold http://www.ls1.com.au/forum/showthread. ... ost1843571 which was allegedly a knock off of Rover's Motorsport inlet manifold (Tom Walkinshaw was involved in both the Rover and Holden manifold).
Attachments
g004.jpg
GRA Tornado Topbox
Every job is a self-portrait of the person who did it. Autograph your work with excellence.

Fuel flow requirements calculations viewtopic.php?f=5&t=1638

gottago
Posts: 200
Joined: Thu May 24, 2012 7:39 pm
Location: British Columbia Canada

Re: Who's run a tunnel ram and propane?

Post by gottago » Thu Oct 08, 2015 1:23 pm

I'm probably going to run this manifold again soon on a motor that I have already tested out for power and mileage with a dual plane manifold and single ohg. So will have a pretty good comparison someday, same compression heads and cam for both. I quit on this manifold before due to the carb throttle actuation system not being so compatible with the 700r4 transmission actuation requirements. Suited the turbo 400 trans linkage but not the od trans without some more work. Also a fair bit more to setting up and coordinating those gras compared to the others.

The tpi would be an interesting unit to try out. Franz says it isn't really suitable due to distribution issues. If you can solve that with some custom diffuser tubes or something along that line, would be one of the best for a torkey propane motor imo. Turbo-d may work real well too.

Good to hear you got your motor running nicely kikka.. I use a 2 inch spacer on most of the single mixer setups if there is hood clearance.

User avatar
kikkegek
Posts: 371
Joined: Thu Nov 17, 2011 2:12 pm
Location: Netherlands, The Hague

Re: Who's run a tunnel ram and propane?

Post by kikkegek » Thu Oct 08, 2015 1:31 pm

gottago wrote:
Good to hear you got your motor running nicely kikka.. I use a 2 inch spacer on most of the single mixer setups if there is hood clearance.
thanks man. I borrowed LM-2 dataloger and will do a baseline test to check difference in AFR before and after adding the spacer. I read everywhere that a Spacer will lean out the mixture and people add bigger nozzles (is that the correct word?) to their carbs.

I think the Edelbrock RPM Air Gap might be a good replacement for the TPI intake when combined with 2 inch open spacer. it has thin runners and spacer will add the advantage of open plenum. They arent even that expensive on Ebay... about $150,- including shipping

Image
daily: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.1 end gears - IMPCO425 mixer - IMPCO model E vaporizer
project: 1977 GMC C15 Suburban - 454 big block - TH400 - gasoline
sold: 1986 Chevrolet Suburban K20 Silverado

User avatar
kikkegek
Posts: 371
Joined: Thu Nov 17, 2011 2:12 pm
Location: Netherlands, The Hague

Re: Who's run a tunnel ram and propane?

Post by kikkegek » Thu Oct 22, 2015 2:14 am

wel, I added the 2 inch open spacer this week and its running fine.

Image

Image

Image

why did I do it? well I read on a couple opf forums that propane loves big open spaces, because it expands a lot when it warms up. And I read that small blocks might respond better, because the pulse in the runnes would be better when a 1.5 or 2 inch spacer is added.

And I was just curious...

The O2 sensor shows no difference in AFR before or after...maybe a slight little bit leaner...but it wens maybe only from .82 to .85 on WOT and .92 to .95 on cruise and idle. I know, these are not optimal values, but for now they are fine and I wanted to know before and after values.

I think I ontice a little more torque on low end and it seems to rev up higher when doing WOT runs...from what I can hear...did log it and its hard to keep my eye on the tach when doing WOT runs, hahaha
daily: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.1 end gears - IMPCO425 mixer - IMPCO model E vaporizer
project: 1977 GMC C15 Suburban - 454 big block - TH400 - gasoline
sold: 1986 Chevrolet Suburban K20 Silverado

gottago
Posts: 200
Joined: Thu May 24, 2012 7:39 pm
Location: British Columbia Canada

Re: Who's run a tunnel ram and propane?

Post by gottago » Wed Jul 19, 2017 4:25 pm

Tunnel ram has been run for awhile now so have a few results and comments. Same test engine, 3rd cam, 3rd intake .. This is the best way to go on this engine by far. (high compression 377 cu. in. sbc) Excellent broad range of power and great fuel mileage. I even retarded the cam. 112 lsa 234@50 in/ex 480 lift. Now running two impco 425 off of two ohg x1 vapourizers. Changed to the blue springs in the x1. One glitch, not as smooth at low rpm as the orange springs. It has a rich spot afr 14 at idle that then goes right lean, 17.5 + at a light crack of the throttle. If I adjust the idle afr leaner, it goes too lean off the scale when the throttle is cracked open. Otherwise I am very impressed with what the tunnel ram does. Would like to straighten the idle situation out and keep this combo as is. Suggestions?

User avatar
kikkegek
Posts: 371
Joined: Thu Nov 17, 2011 2:12 pm
Location: Netherlands, The Hague

Re: Who's run a tunnel ram and propane?

Post by kikkegek » Wed Jul 19, 2017 5:00 pm

cool feedback. photos?

and how is it better then your previous setup?
daily: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.1 end gears - IMPCO425 mixer - IMPCO model E vaporizer
project: 1977 GMC C15 Suburban - 454 big block - TH400 - gasoline
sold: 1986 Chevrolet Suburban K20 Silverado

gottago
Posts: 200
Joined: Thu May 24, 2012 7:39 pm
Location: British Columbia Canada

Re: Who's run a tunnel ram and propane?

Post by gottago » Fri Jul 21, 2017 4:03 pm

The surprising part to me was the low end torque. I expected more up high and it did that too but it was spread through the entire rpm band right from idle to 6000 rpm + . The mid range is phenomenal, extremely responsive. The last setup was more peaky. I haven't done an exact mileage test but it is very good. Last setup was about 16 mpg, just judging by that I'm nearer twenty now. Costs me about 25% less to drive the same distance. ( I did retard the cam a few degrees too so not sure what that contributed) I'll try to get a few pictures next while.

User avatar
kikkegek
Posts: 371
Joined: Thu Nov 17, 2011 2:12 pm
Location: Netherlands, The Hague

Re: Who's run a tunnel ram and propane?

Post by kikkegek » Fri Jul 21, 2017 5:36 pm

cool!

and is it the tunnelram you modified and shared in october 2015?
daily: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.1 end gears - IMPCO425 mixer - IMPCO model E vaporizer
project: 1977 GMC C15 Suburban - 454 big block - TH400 - gasoline
sold: 1986 Chevrolet Suburban K20 Silverado

gottago
Posts: 200
Joined: Thu May 24, 2012 7:39 pm
Location: British Columbia Canada

Re: Who's run a tunnel ram and propane?

Post by gottago » Sat Jul 22, 2017 3:09 am

Its the weiand mini ram with an adapter on top now that replaces the box the gra's were mounted to and mounts two carbs straight up instead. . You can get that base alone to fit most any application. I'll get a photo in the near future.

User avatar
kikkegek
Posts: 371
Joined: Thu Nov 17, 2011 2:12 pm
Location: Netherlands, The Hague

Re: Who's run a tunnel ram and propane?

Post by kikkegek » Sat Jul 22, 2017 11:28 am

gottago wrote:Its the weiand mini ram with an adapter on top now that replaces the box the gra's were mounted to and mounts two carbs straight up instead. . You can get that base alone to fit most any application. I'll get a photo in the near future.
dont make us waite..... ;-) :shock: :lol:
daily: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.1 end gears - IMPCO425 mixer - IMPCO model E vaporizer
project: 1977 GMC C15 Suburban - 454 big block - TH400 - gasoline
sold: 1986 Chevrolet Suburban K20 Silverado

gottago
Posts: 200
Joined: Thu May 24, 2012 7:39 pm
Location: British Columbia Canada

Re: Who's run a tunnel ram and propane?

Post by gottago » Sat Jul 22, 2017 3:35 pm

Ha, for those who can't wait, this is a picture of how it began ...
https://www.holley.com/products/intakes ... parts/7540

and this is what you end up with after replacing the top box with the adapter piece...
http://www.superchevy.com/how-to/projec ... all-block/

Post Reply