Inliners International Forums General Discussion Hi Performance Lump kit results/gains?

Hi,

I'm getting started installing intake lumps in my 230, and someone asked me "Why". I told him "Because I CAN, and I'm curious". Then he asked how much more power do you gain. I couldn't tell him.

So.... does anyone have dyno results or even seat of the pants or 1/4 mile times that show the difference before and after lumps?
I would love to see what they ALONE can do. Zero other mods.

Failing that, any feedback (with measurable results) on any street engine combo would be welcome.

Failing that... just tell me your seat of the pants experiences.
How does it FEEL compared to no lumps.

Forever curious

jan

How is dyno testing results for you? If OK, , ask Tlowe.

MBHD

Thanks Hank. I found some dyno numbers but other mods were done too, like bigger valves. I would like to know the effect of one component alone, and at the end doing several measurable mods to an engine, it would be interesting to see if the sum of mods is greater than the individual power-adders alone. Which it should be. The lump mod is one of the most discussed one, but I am having hard time finding measurable gains from that one mod alone.

Since you asked what the "lumps" gained with no other mods done, that was one of the first tests performed, and the result was zero gain. Its not until you start to increase the cam and valve sizes that you will begin to get any increase from the "lumps".

Thank you!! Any unmeasurable benefits like better throttle response?


this engine has a mild cam, zero deck, 9.5:1 CR or so, and minor tweaks here and there. I kept the stock valve size it's a 230 and I was hoping it would have better low end that way. It won't be a high rpm build. I guess more of an "optimized", efficient little motor.

Since you do have a larger cam along with the "lumps", they will compliment each other and you will get some gain for them in that case.

In dynoing, Scott is right. First test done was exactly what your are asking. Do the lumps help in a otherwise stock head. The short answer was no.
Starting with larger valves and porting was done next. Major HP and tq was found, even with the stock cam.

Lastly, changing the cam compounded the power gains a equal amount as the performance head.

P.S. Heard from a customer tonight. He ran a PES intake on a Dyno and witnessed a 7% gain over a Clifford. Take it or leave it. This was a circle track setup with a 2BBL.

Suggestion:
If you have a way to do it, get the car out to the strip and get some timeslips before & after. Might be a bit too late in the year though for that. Or with a Gtech or something like that. Its not going to be a world of difference, something you might feel or think you feel but could see it in the times and G's recorded.

Thats how I did the carb/intake shootout, "seat of the pants" doesnt work for me - it always feels faster if I spent time or Money on it, but that doesnt mean its really so!

Thanks again guys.

I meant to to a baseline "before" run on the 1/4 mile but never got around to it due to wiped out stock cam lobe. (That's how I got the car, plus a chunk missing from one piston... but it ran) It would have been pointless. The engine is getting close to being done. Need the lumps done and studs and push rods, little bits and pieces like that.

This car will likely never see a track, it's just a weekend cruiser, 4 door grandma car.

My Gtech is 6000-7000 miles away. Not even sure where, probably in the same box with a Crane CDI box

And yea, if I spent money or time on a mod, damn right its gotta be faster Just like louder exhaust makes it go faster. And Moon eyes/thrush woodpecker stickers are worth 10hp each.

Edit: radiused sharp edges, blended seats, light port work (no polish, surface cleanup, coned guide bosses) unshrouded the valves but kept the tub well defined and close to original, deep and narrow with plenty of quench plane), gasket match (head, intake, exhaust)

70Nova, You may have posted this before but can you please post what camshaft will be put in the 230. I am going through the cam selection prosses and would like to know as much info as possible. Thanks. Jay

Comp Cams 240H - the mildest one on the list (Tech Tips link from the main page here). I ended up doing more mods than I intended and now I would probably choose a step or two hotter cam and high performance springs to go with it, which I may still do. But it sucks because I already have the brand new cam, lifters, stock type springs, ready to go on the engine. Argh. The 240H is the only grind from Comp Cams that works with stock springs, no $$ hi-po springs needed, no need to modify rocker studs, no need for higher compression ratio, etc. etc. etc... it is a cam designed to run in an otherwise stock engine with stock or slightly higher Compression Ratio. It keeps the build cost lower while optimizing what you have making it run more efficiently.

My plans have evolved and I have put some more labor and money into the project, and the engine could now support a bigger cam, with just a spring change.

I can't say how well this cam works, zero experience since it hasn't even been installed yet. The engine is still in pieces, more machine work to follow before assembly. So all info I have on that grind is from others, on this forum and elsewhere online. It is supposed to have a noticeable improvement in the stock rpm range, just slightly deeper idle sound but smooth like stock.


Cam and lifter combo ordered in 2012 was just under $200, free shipping. Buy a matching set, not just the cam.

Jan

Thanks for the reply. I will be looking forward to learning how the nova runs with this cam or whatever one that you choose to run. My only experence with aftermarket cams for a chevy 250 was a Crane 203901 in a 79 gmc half ton p/u that I bought new. I replaced the head with a brand new one because of cracks and burnt ex valves. Other than standard sbc valve springs the head was stock. I also adapted an autolite 2100 carb with dual exhausts. The truck went from being out of breath at 45-50 mph in 2nd gear to pulling hard all the way to 65mph. Ch465muncie,3.40 gears 27.8 in tires. But gas milage was down and I lost some low speed Torque. Knowing what I know now I should have done something to up my compression. Hope this helps. Jay

well the 240H is as close to direct bolt on as you can get, designed to run well with EVERYTHING else being factory stock, even compression ratio and springs. That was my plan, a stock rebuild with an efficiency increasing cam.
I have SBC springs btw.
Anything beyond this necessitates aftermarket springs. And that in turn requires changing rocker studs from press-in type to threaded type (another $120 trip to the machine shop). The hotter comp cams high/extreme energy cams are also designed to run stock compression (8.5:1) or up to 9.25:1 but you will need other mods to make them work properly. The 268H is the biggest of the series that can still use a stock torque converter, although I saw some people disagreeing. That's why it would be my choice for an actual performance cam without having to spend even more money on other junk just to be able to run it.

I am almost certain I will never install the 240H and just go straight to the bigger 268H. I can then fall back on the smaller cam if I don't like it, but I will need to get a new lifter set for it to break it in right and I will need to set the valve/rocker geometry again.

70Nova, Changing from a 240h to a 268h seems like a HUGE jump up in cam size to me. I looked in the Comp catalog and they list the same spring for a 240,252,260h cams and also for a 252 in a sbc. IIRC this is a 230 right? If so the same cam will act bigger than in a 250. If you were to pick a 252 or 260 cam it would be at least worth the trouble to check for coil bind clearance with the sbc springs that you have. If this works it could save some money at the machine shop. The lumps in the head will let you get away with a smaller cam and have the same performance as a non lump with a bigger cam. There are LOTS of people with WAAAY more knowledge than me. There are also other cams. SCRAPIRON,#4711 ran a mercruiser cam that he liked. I don't know the specs maybe he will chime in. Can you also post what trans and axle that will be used? Jay

Jay, the 268H is a big jump, but an intentional one.

Let me explain.

This build was originally supposed to be just a stock rebuild, while I look for a 292 core to start a big build on. My intention was to kind of keep costs reasonable, but optimize what this engine has as much as I can. When it became obvious that the old cam had a badly worn lobe I knew I was going to put an "optimized" cam in. Whenever I have to pull a stock cam out, I don't put another stock cam in, makes no sense to me. So I was happy to find the mildest Comp cam that was designed to run well with EVERYTHING ELSE being bone stock. Just what my original plan called for.

I had a few self-imposed constraints to work with: time and money mostly. I wanted to get the car back on the road this summer (2013). It's been parked for 2 years now and I'm dying to drive it. Well that schedule set certain budget limits for the build.

Fast forward to today: due to several minor things working against me, and a surprise addition to the family that needed a partial motor rebuild (Chevy Aveo, don't laugh), I gave up on my target date of this summer. So that automatically buys me at least the whole winter time wise, and this means I have time to save more money for the build too. Plus driving the Aveo vs. my Jeep saves me a TON of gas money that I can now redirect to the engine build! So I optimize things a little further. I managed to find more compression by zero decking the block in addition to milling the head, I originally thought I would have to settle to something less than 9:1. But now I have 9.5:1 which could support a bigger cam. Again for the sake of optimization I decide to do the lump port modification, especially after running into a cheap set of lumps on Ebay. I do most of my metal work and engine building myself, only farming out some milling. So it's "free" labor.

As my plans evolve and I am able to throw more money at this project, and especially after spending more money to build an engine that COULD make more power... I'm now asking myself, "So why don't you LET it make more power?"

So the almost-stock 240H cam will need to be replaced with something MUCH more performance oriented, that would still work with my compression, carburetion and exhaust options and stock torque converter. So I would not want "the next" little cam, but a clearly hotter one.
I am not afraid of BIG cams, I have built engines with cams so big they had to be custom made, you couldn't buy those numbers off the shelf. They just require high CR to make them run right.
My cam grinder showed me profiles that he had designed, that require 20:1 compression ratio. Gasoline, not diesel. "Can't be done" is the first thing that comes to most peoples mind. But that's another story.

This means stepping up my game and spending even MORE on the build, not just switch the cam out at the last minute. I'll have to make the valve train stronger. Simple stuff really but another 300-400 bucks more. I can justify it because it would make all my other optimization work more meaningful. I was doing a lot of high performance tricks for a stock rebuild. Makes no sense to most folks but that's how I build them. But it IS kind of a waste. Now it won't be. With the bigger cam and higher state of tune, it is all well justified and fits the changed build plan just fine. AND I can still go back to the smaller cam later if I feel like it, without making changes to the engine.

About the SBC springs, from what I have learned, they won't work with the 268H. So be it.

Can't wait to get my head back from the shop to start measuring and mocking things up for .499 lift instead. Sometimes the journey is at least as exciting as the destination, if not more so for me.

Not %100 sure on the cam choice yet.

As for trans and axle, I will be killing all the fun with the stock 2sp powerglide and stock rear for now. First the engine, then body work and interior, and then maybe trans and rear. Being an automatic, I don't care what it is, it'll always be a buzzkill. For me, a performance car has a manual transmission. And they can corner. And they are light and nimble. THIS car is a heavy 4 door ocean liner.

Edit: my weekend warrior is a stroker big cam custom 68 VW beetle convertible. I just need to ship it from my parents house to me, some 6000 miles. It has maybe 1500 miles on the engine and it will run circles around any Nova.