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So I'm stuck of intakes with my project and thinking about making carb like spacers to make the runners 2-3" longer on a stealthram. I found some 3" thick by 5" wide plate aluminum and I'm going to attempt to drill 4 holes and open them up to match the runners. Stock runner is 12.26"+3" spacers is 15.26" vs an accel superram that I have welded and ported the snot out of with the runner walls ported down about 2ish" so 21"-2 they should be about 19" now.... Looking for good TQ and HP into 6k rpm. 356 motor 195afr comp ported heads, xfi custom cam 224-230 .560s lift 112. In a 92 Chevy c1500 2wd truck. Hoping for lots of low end and 370-390+hp. Anyone ever done this before?
Havent seen it done on this intake before but seen it done on ITB intakes. Adjustable runner lengths. It does tune the rpm range. You should see more trq
Wow now that would be perfect! Never knew thay made these! I know it will pull up high but I want to lower the TQ curve some
Dumb question here, why not move to a smaller duration cam to gain power down lower where you want it?
When my LT1 swap was just a bolt-on car I had more than enough torque to satisfy and it was flat as a table top with power extending to 5500rpm on the stock cam.
You want to move more air at the same time as tune for a certain rpm range. Longer runner with good head and longer cam will build more torque overall. What you need is a fast cam lobe and a really good head port to maximize torque output but that hurtsvalvetrain life somewhat
I found some 2 inch spacers on eBay for 210 dollars or is it worth buying block that's three inches tall for $60 and trying to make them myself is the extra inch worth it? The eBay spacers I have been told will fit the stealthram even tho there made for the tunnel ram
I did a quick simulation run on an older setup I had with a flat-top 355 and StealthRam making around the 430HP mark with the stock length HSR. I know that the simulation was very accurate compared to the actual dyno results, so doing nothing more than adding 2” and 3” to the runner length should give you an overall impression if the added costs would be worth it to you.
Here’s what it shows should happen on that engine. While not exact, the percentage increase should hold fairly constant on similar powered engines. So,,, there was an increase of peak torque of around 1.7% (7 lb/ft)with the 2” extension and about 2.4% (10 lb/ft) with the 3” extension.
What the graph shows that the peak and average numbers don’t tell is there is around a 3.8% (14 lb/ft) increase in torque at 4,000 rpm and around 3.5% (13 lb/ft) at 3,400 rpm between the stock and 3” extension. That’s a definite seat in the pants increase concentrated in the “playing around” rpm zone.
I'm liking what I'm seeing! I'll have to double check and see how tall I can make this HSR before it hits my hood....might have to try for 4" spacers. If the TQ curve goes up again with a 4" vs 3" id be happy while keeping peak HP close to 6k with my head/cam choice. I'd like to keep from spinning my short block much past 6k
I was running a set of Gen1 TrickFlows that flowed around 245cfm at intake lift and running a 218/228-110, .493/.501 cam on a 9.8:1 compression 355 – it was making 430-ish FWHP. I was running 1-5/8” “shorties through a single 3” pipe to a welded DynoMax single in dual out muffler. I had to shift it at 6400 rpm to get the best ETs out of the car and like you I didn’t particularly care to run the engine up that high. I would expect your combo would make around 460-480 FWHP (or around 370-385 rwhp with an automatic - depending on runner length and exhaust system). I would also expect you would need to shift around 6600RPM with the stock length StealthRam – maybe a little more with a good exhaust system (better than what I was running on mine).
FYI - I actually pulled off the HSR and put on a box stock FIRST and ran fractionally quicker times, although I did experience a 1.5mph drop at the end of the quarter – shifting at 5800 and 5600 rpm.
Edit - I ran another simulation and going from 3-4" spacers added another 4-5 lb/ft. For what you're wanting, definitely the longer the better.
I have spacers for my stealth ram. I haven't used them due to hood clearance issues at the moment. But I will when I get a new hood. I got them from the guy I bought it from. The larger set seems to machined from someone not bought from a store.
`They don't make spacers for the HSR, the HSR is based on a common Tunnel Ram intake and the pattern is pretty much the same from weiand to holley etc... They make spacers flor those. They fit just fine, just like the gaskets for those tunnel rams fit fine. The lower manifold on a holely stealth ram is a weiand hi ram with injector bosses. nothing more.
Glad to see you adding the extra length to the runners. It looks great and I'm sure you'll be very pleased with the output. The extra midrange will really help move the truck a lot better at the shift recovery point, preventing you from having to run the RPMs up as high as you have to do with the standard length HSR.
Still have yet to get if off Jack stands as I'm working on the exhaust system. Will 3" header collectors off LT headers into a 3" wye and a single 3" magnaflow be choking off this setup? I do have a duel 3" in single 4" out big magnaflow muffler I could use....
Yes, keep us posted. Hey at least it gives more thermostat and fuel rail clearance!
I have considered going the other way, shortening the runners. Mostly to pick up some clearance before the throttle body grinds a hole through my hood. Plus it should help on the top end. Looks like you have lots of room.
It's up and running. The new xfi cam sure sounds healthy and choppy....I love it. It revs to the moon crazy fast with the blurp of the throttle. I have backed it out of the garage to clean up the mess I made over the winter. Other then that I'm thinking I'll need to wait tell spring to take it for a tune. I'm scared to drive it around with the old tune.....how bad is it to run this engine off the old tune i'm running now? Old tune is for old cast heads 212-218 .509lift cam vs AFR heads 224-230 .570s lift setup?
As long as it runs good and doesn't get too lean you should be fine. If this is a speed density system you may need some changes due to the cam and I'm sure there are tweeks for the intake modification. If you are MAF it will be less noticeable.
It's a MAP setup. I'll be running with runner pro rt and a ostrich emulator. I found a local shop that says they have done TPI maf and map tuning. Hope they know what there doing cus I have yet to figure it out. It idles fine and smells stupid rich.....so rich that it burns your eyes and the water that comes out of the tail pipe is dark in color. Just not sure I want to put it under a load driving around. I'm running 24lb injectors from the old setup now but can change to some 30s and or 32s I have.
It's a MAP setup. I'll be running with runner pro rt and a ostrich emulator. I found a local shop that says they have done TPI maf and map tuning. Hope they know what there doing cus I have yet to figure it out. It idles fine and smells stupid rich.....so rich that it burns your eyes and the water that comes out of the tail pipe is dark in color. Just not sure I want to put it under a load driving around. I'm running 24lb injectors from the old setup now but can change to some 30s and or 32s I have.
Probably should put a wide band on it to see what the AFR is (or at least a scanner to see fuel trim values).
Assuming everything is in order from electrical/mechanical perspective, it sounds like your VE tables are so far off that the ECM has run out of adjustment range. Even if the BLM (long term fuel correction indicator) is off from the ideal 128, it'll still idle at the correct fuel mixture. But if it's pegged at 108, then it's out of adjustment and after that point yeah, i'll just keep getting richer.
For a reference, I idle around 13.0:1 AFR and it doesn't smell like anything more than a typical high performance small block. So you must be down around 12:1 or less...
When my LT1 swap was just a bolt-on car I had more than enough torque to satisfy and it was flat as a table top with power extending to 5500rpm on the stock cam.
Agreed. I"m running a Miniram (probably the shortest runners of any aftermarket intake available) and there's absolutely no shortage of low end torque. If I stand on the throttle at any speed in first gear (including from a standstill), it'll literally just spin my 285's the way up to the point that I shift into third. Cam is a little more radical than stock, but is still singing past 6000...
Are the ports on the Intake large enough to cover 220 cc heads.I have wanted to use the Stealth Ram but I don't know if it will work with my heads.I had a built 89 pick up truck and miss it.Keep us informed on your progress 355TPIpickup.
Last edited by Steve Mack; Feb 4, 2016 at 07:49 AM.
Reason: add info
It would be close that's for sure. I have the older HSR base and the 1206 is stupid close but no intake leaks so it sealed up. I'm looking at getting a newer style HSR base for more room to port on the intake /head side....the 1207 might work on that new HSR vs mine
That's good to Know that you are using the old style base and could get the ports out to a 1206 gasket.I think the new base has more meat to port larger.Thanks for the info.
Well bad new.....I was changing oil 30mins of total run time if that since the head/cam/intake swap and found what I think is coolant. So it looks like I get to pull it all apart again. How could I tell if it from the intake or head gasket? It never smoked and seemed to be running good.....other them smelling very rich. <a href="http://s77.photobucket.com/user/moncarr6/media/Mobile%20Uploads/IMG_20160213_172604.jpg.html" target="_blank"><img src="http://i77.photobucket.com/albums/j71/moncarr6/Mobile%20Uploads/IMG_20160213_172604.jpg" border="0" alt=" photo IMG_20160213_172604.jpg"/></a>
Good news is the oil color was just lube and carb cleaner from the build. Bad news is I have alot of ticking noise on the passenger side. I readjusted the rocker arms but still sounds like a header leak. I have checked the header and don't see any black marks showing a leak....maybe a bad lifter? Or a valve not seating? I just finished my exhaust and installed my cats back on and it seems to have made the noise louder. Maybe from more back pressure now? I'm nervous to take this for a drive with this noise....any ideas guys?
It depends on how loud it is if I would drive it or not. My setup is a comp custom cam with 236/242 duration and ~600 lift, with the comp 1.6 full rollers the valve train is loud. There are a couple of rockers that are louder than others. I have thick hood insulation and I can hear it with the hood shut. I adjusted the rockers with different amounts of preload running when up to temp. I have swapped out different length push rods and it is still there. After almost 2 years of daily driving and trying so many different things I have concluded that the noise is something that just is going to be there. It isn't like a sweet sewing machine sound and not quite as bad as a collapsed lifter but it is there and quite frankly I hate it. If I ever change cams I may go with a less intense lobe profile. You may have a problem then again it may just sound that way.
