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LOOKING FOR SOME HELP
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jeep_406
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Joined: 12 Sep 2002
Posts: 1661
Location: Tewksbury, Mass 01876
53123.48 points


1972 Chevrolet Nova

PostPosted: Wed Nov 18, 2009 3:06 pm    Post subject: LOOKING FOR SOME HELP Reply with quote

I've got the engine out of the Nova. We're going to dyno it and then change camshafts and then re dyno it. Switching to an Ultradyne Hydraulic Roller. 245/249 @.050
.612/.612 lift with 1.6 rocker arms
Separation 109 degrees.
Installed @ 105 degrees.

The cam being replaced is a Comp Hydraulic Roller.
236/242 @ .050
555/576 lift with 1.6 rocker arms
Separation 110 degrees
Installed @ 106 degrees

I'm looking for 25-30 horses as I continue the quest for high 10's next year.

If I don't get the number with the cam change and tuning I'll probably see if I can increase the flow on the intake side of my Sportsman II heads. I was thinking of changing over to aluminum heads but I don't really have the money to make that move. And I'd like to see if I can find an increase in the heads I have. Won't cost anything but my time and some gaskets to work on the heads. Last time I went through the heads the intakes were increased to 2.055 valves but I didn't see any appreciable increase in flow over the 2.20's. The flow figures on the intake are 250 @ 28 inches. The exhaust flow quite well at 212. These readings are at .600 lift. They originally flowed 237/143. I use a Superflow 110 which is probably older than a lot of SMOKESTERS but it works within the specs it's supposed to. I'm figuring that an increase to 260 or so on the intake would bring me about 10 ponies. Any thoughts would be appreciated.
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squeeezer
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Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Wed Nov 18, 2009 4:53 pm    Post subject: Reply with quote

will you expect to get more rpm out of this motor with the cam change????

id say cylinder headswill be the big change

what kind of power are ya getting right now????

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jeep_406
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Joined: 12 Sep 2002
Posts: 1661
Location: Tewksbury, Mass 01876
53123.48 points


1972 Chevrolet Nova

PostPosted: Wed Nov 18, 2009 6:45 pm    Post subject: Reply with quote

The old cam would go to 7k feeling seat of the pants strong but the timeslip never lie and the car goes just as quick shifting at 6000-6100 RPM. This new cam should bring me closer to the 7k. The new cam will take away some lower end. Losing lower end may help keep me from blowing the tires away when launching.
The difference in cams is 9 degrees duration. I'm told that I should see a gain of 8-12 HP for each 4 degrees.
I only have a Dyno 2000 program. Using it shows me losing a ton of torque and only marginal HP increase in upper rpm numbers.
With the new Ultrdyne cam Dyno 2000 figures show 530 HP @ 6000rpm with the Sportsman II heads. For comparison the same cam with the new 220 Comp AFR Aluminum heads show a maximum HP of 586 @ 6500rpm. They would definitely get me into the 10's but I just don't have the cake for that now.
I could lose some weight by getting rid of the working AC and put on fiberglass bumpers but the AC makes it different and it's a great feature in the dead of summer.

I figure the engine is putting out around 520-525 HP as it sits.
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squeeezer
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Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Thu Nov 19, 2009 12:39 am    Post subject: Reply with quote

i cant help but to think you may be disapointed by only changing these cams

your so close though maybe on a good day youll get your 10
but whos to say you wouldnt have done so with the old one?

if your powerband goes up 500rpm or so how will you take advantage of this as far as gearing and or shifting goes
i suppose tnt ultimately will decide
hope you dont go slower from the loss of low/mid range tq

i say solid roller swap
head swap
or both really

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SMOKEmUP
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Joined: 30 May 2002
Posts: 3169

65093.54 points


1979 Chevrolet Camaro

PostPosted: Thu Nov 19, 2009 10:38 am    Post subject: Reply with quote

Since the engine is going on the dyno what about playing with carb spacers and/or turtle inside the intake.

Another option for 10's is weight reduction.

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Paul P
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Joined: 15 Aug 2002
Posts: 2393
Location: Townsend, Mass.
81240.86 points


1971 Chevrolet Chevelle

PostPosted: Thu Nov 19, 2009 11:05 am    Post subject: Reply with quote

Hey Jeep,
My sportsman aluminums in their current state are flowing 260 on the intake. Kenny ported these at the old shop in Westford.
I am using a bit more cam as well and the car is lighter at 3500 with me in it. On a good DA day was the only time I was able to get in the 10's. 11.0's on other days.....
You will get there with the cam I think and a bit of weight reduction would not hurt being as close as you are.

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2001 Focus 2.0 Zetec
15.63@87 MPH 1/4mi
1971 - Chevelle 408 SBC N.A.
6.95@98.6 MPH 1/8mi
10.97@121 MPH 1/4mi
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jeep_406
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Joined: 12 Sep 2002
Posts: 1661
Location: Tewksbury, Mass 01876
53123.48 points


1972 Chevrolet Nova

PostPosted: Thu Nov 19, 2009 1:12 pm    Post subject: Reply with quote

I plan on dynoing the 408 as it sits with the same jetting, timing etc as the last time it ran to get a base number. We're going to dyno it with my headers although it won't have my exhaust on it.
I ran the 408 with 2 one inch spacers, a 4 hole and an open spacer. I also tried 3 different carburetors and various degrees of timing. I didn't try a turtle. To be honest I didn't even think of it.
When we make the cam change I plan on making a number of pulls trying various jetting, timing, etc and probably a few different carbs.
I'd like to find 30 horses. If I don't find 25 then I'm figuring on playing with the heads. Another thought is to try a vacuum pump.

Paul,
Kenny and Paul Rinaldi are certainly a little higher on the food chain than I am. Maybe I'm asking for too much from my cast Sportsman II's. I've got the average flow up to 250 @ .600 lift. Paul R. installed 2.055 valves. When I flowed them I didn't pick up any more flow. I spent a few hours on them and didn't get any increase. I figured it's something I'm missing. I picked up a ton on the exhaust side but a much smaller margin on the intakes.

Brain,
The only day I got up to the track this year with really exceptional DA there was a stiff head wind.
I know if I switch to a good set of aluminum heads I'll pick up a enough to get into the 10's easily. Maybe my stubbornness as well as the lack of cash keeping me from making the move. I'm retired so I'm only out my time and the cost of some gaskets, oil, etc.

Thanks for the thought. I'll keep you posted. Hope to make the changes next month. Depends on when I can sneak the 408 onto the dyno.

Right now they are dynoing LS combinations. Saw one carbureted LS with 454 cubes if I remember correctly. It cranked out 721 HP with 606 foot pounds of torque. That was without any spacers under the carb. Most of the engines they build are Injected. I was suprised to see a carb on it.
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Knarley Darley
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Joined: 22 Apr 2004
Posts: 1247

540230.26 points



PostPosted: Thu Nov 19, 2009 3:05 pm    Post subject: Reply with quote

Did you do a valve job for the increase in valve size, or just try putting a bigger valve in on the flow bench. The larger diameter valve will increase flow if the seat is opened up to take advantage of it. I too am skeptical about the cam change. I think it probably will increase power a little, but trade a lot of streetability which may be worth it to you. I dont think torque will be a problem because of your engine size. Keep us posted
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jeep_406
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Joined: 12 Sep 2002
Posts: 1661
Location: Tewksbury, Mass 01876
53123.48 points


1972 Chevrolet Nova

PostPosted: Thu Nov 19, 2009 3:38 pm    Post subject: Reply with quote

I opened below the seat for the bigger valve. Don't remember off hand but I believe I cut it to somewhere between 85 & 90% of the valve size.

I can probably stand to lose a little lower end. I run a 700R4 with a Precision Industries lock up converter that flashed to around 4000 RPM. With a 3.06 first gear and a 4.10 gear with 28 inch tall tires it launches very well as long as I keep the rpm under 2000 at the line. Above that it unloads the rear tires. During a pass down the quarter mile the engine comes back to 51-5200 when it shifts. I lock up the converter in 3rd gear at 5800 RPM. I usually pick up 1.5 to 2mph by doing this. If I lock it up at the beginning of 3rd gear it slows the car down. If I mistakenly let it go into 4th gear it slows the car by at least half a second. Embarassed

I run Mickey Thompson 275/60R/15 drag radials. They are the biggest tire I can fit under the car.
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Paul P
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Joined: 15 Aug 2002
Posts: 2393
Location: Townsend, Mass.
81240.86 points


1971 Chevrolet Chevelle

PostPosted: Thu Nov 19, 2009 4:10 pm    Post subject: Reply with quote

Kenny was telling me back then that he lowered the floor on the intake and it kept picking up flow. Might be worth a try if you have time to put it on the bench.
_________________
2001 Focus 2.0 Zetec
15.63@87 MPH 1/4mi
1971 - Chevelle 408 SBC N.A.
6.95@98.6 MPH 1/8mi
10.97@121 MPH 1/4mi
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Skunkworkx
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Joined: 02 Sep 2007
Posts: 352
Location: Harford Co. Maryland
10318.16 points


1968 Chevrolet Camaro

PostPosted: Thu Nov 19, 2009 7:26 pm    Post subject: Reply with quote

I would think a little clean up in the runners,a gasket match,with a bit of chamber work would be better than the cam swap and a lot cheaper than AFR's.
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af2
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Joined: 01 Sep 2003
Posts: 5557
Location: grassvalley, ca
71191.50 points


1933 Willys Coupe

PostPosted: Thu Nov 19, 2009 7:42 pm    Post subject: Re: LOOKING FOR SOME HELP Reply with quote

[quote="jeep_406"]
I use a Superflow 110 which is probably older than a lot of SMOKESTERS but it works within the specs it's supposed to.
quote]

Jeep, I still have the SF110 I bought in 1991 for doing Outlaw cart cylinders. I haven't tried to use it on bigger stuff because of the low(10") water column involved vs 28" on the smaller ports. If you can flow at 28" and above you can find a whole bunch of weired crap going on with a port.

I would agree a Hydro cam change won't do it (30 hp).
A solid will keep the power longer though and probably net that much above 5000.

The pushrod pinch is narrow in those heads. That would be the first place I would spend time measuring as not to break through.

I would also forget the exhaust flow. I really means nothing when mufflers are used as far as I have read and with proof.
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jeep_406
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Joined: 12 Sep 2002
Posts: 1661
Location: Tewksbury, Mass 01876
53123.48 points


1972 Chevrolet Nova

PostPosted: Fri Nov 20, 2009 12:49 am    Post subject: Reply with quote

I've lost track on the number of hours I have in these heads.
When I first worked on them in 2000 they started with 228/148 @.550
Last time I checked them the average was 246.5/206.2 @ .550 and 250/212 @ .600 lift. Obviously I did a ton of bowl work, back cut the valves, did a 5 angle seat, etc.
I've done all the work on the Superflow 110 at 10 inches and used the formula for the 28 inch readings taking into conditions the change in temp.
I got most of the improvement in the exhaust working with the short side radius.
If I go into the heads, and I'm pretty sure I will, I'll try taking out some more floor on the intake side.

Thanks for the suggestions
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Paul P
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Joined: 15 Aug 2002
Posts: 2393
Location: Townsend, Mass.
81240.86 points


1971 Chevrolet Chevelle

PostPosted: Fri Nov 20, 2009 12:01 pm    Post subject: Reply with quote

Jeep,
I'm pretty sure that it was the middle of the port floor on the intake that he was working. This would I guess thinking about it make the short turn longer as air would hit the floor as it was being drawn into it.

_________________
2001 Focus 2.0 Zetec
15.63@87 MPH 1/4mi
1971 - Chevelle 408 SBC N.A.
6.95@98.6 MPH 1/8mi
10.97@121 MPH 1/4mi
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af2
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Joined: 01 Sep 2003
Posts: 5557
Location: grassvalley, ca
71191.50 points


1933 Willys Coupe

PostPosted: Sat Nov 28, 2009 10:40 pm    Post subject: Reply with quote

Jeep,
Shoot me an E-mail with you're phone #.
I have a set of new heads you might want.
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