squalor

iTrader: (3)

I have a 93 RX7 with a '01 F-Body LS1 and M6 installed. It weighs 2800 lbs. I recently got a tune and made 321 hp. The tuner thought I could get close to 400 with a cam & headers. My car has TBSS manifolds and a mess of stock size piping to a 3.5" cat back. 1 7/8" headers for my car are $1000. I'm on a tight budget so I'm going to try to use BBK Fox body headers with LS1 flanges. 1 3/4" primary with a 2.5" collector - 2x2.5 into single 3.5.
The engine has LS6 intake and 78mm TB and MAF with a tight 90* turn. I'd like to take out the turn but keep the rest. LS6 block but 241 heads. -10% SFI pulley (more about clearing the sway bar than any HP gain). 12" Texas Driveline clutch and 15lb steel flywheel. Stock F-body ratios to the stock 4.10 Torson rear (which is said to hold 450tq).
I'd like to use the Comp 918 springs with stock retainers and push rods, new seals. I will be installing dot to dot with stock gears and oil pump.
Most of my driving is 45mph to 55mph, around 1000rpm in 6th. It has to have a little pull here and squeeze some gas mileage. There are some twisty roads here so I'd like a broad/flat predictable power band from 4500 to 6000. Occasionally I will go from a dig to 4th but have never been to a strip.
I know you guys get this question all the time; I read them but they don't seem to apply to my situation. What is the right cam for me ? If you can, suggest a common grind so I have a chance of picking up a used one from the classifieds here. Thanx in advance for any replies.

PREDATOR-Z

With headers:
224/230 111+1 LSA

squalor

iTrader: (3)

around .560 - .575 lift ? Would my stock parts and beehives live with that ? How does the greater overlap of a 111 LSA help my cause over a 114. The tuner suggested a 232 duration, did I not explain my driving habits well enough to him ? What is a common grind that is close to your recommendation ?

PREDATOR-Z

For push=rods you really should use at least .080 5/16 hardened.
lifts are .581/.590
more overlap = more power

Close would be TR224/112 LSA

squalor

iTrader: (3)

It's been almost 2 years since I asked this question. Predator-Z isn't around anymore but the more I learned, the more I saw the wisdom of his suggestion.
I have been gathering parts and making some changes. I do have headers and exhaust installed now. Spoolin 1 7/8" with merge collectors and 3" outlets. 28" average primary length with a large spread between shortest and longest but that's what it takes to fit this chassis. From the collector merge to a Flowmaster 2x3"/1x4" merge is 28" also. The 4" mid pipe is 30" , 4" to 3.5" transition 4.5" , 3.5" to muffler 23" , OBX muffler 18" , 4.5" Muffler tip 8"
All that should equate to some rpm that the exhaust boosts but damn if I know what that rpm is.
Parts I have so far for my upgrade:
PSI 1511ml valve springs w/ new oem retainers & locks
Morel 5315 lifters
Progear PG4210 with TrickFlow TFS-K30675600 dampener adapter
BTR basic cam instalation kit
Bare 243 heads cleaned and pressure tested
LS6 hollow stem valves
SCE .041" graphite head gaskets
BTR tty head bolts
A few odds & ends like head dowels, oil pickup O-ring, etc.

Before buying anything else I want to settle on a cam. As some of you know, I've been asking alot of questions. Learned some things and even tried to help some others. I have a text file where I keep some of my cam ideas, give them little names and try to compare. Here are some:
Custom cams
2 down 222/226 .612CMo/.603CMo 113+1 LSA/ 112 ICL -1>IVO 43>IVC 47>EVO -1>EVC 114>ECL -2 overlap
0 out 222/226 .607XFI/.600XFI 112+1 LSA/ 111 ICL 0>IVO 42>IVC 46>EVO 0>EVC 113>ECL 0* overlap
Ace 223/227 .610LSL/.571RPR 112+1 LSA/ 111 ICL 0.5>IVO 42.5>IVC 46.5>EVO 0.5>EVC 113>ECL 1* overlap
1 up 222/228 .602LXL/.573XE 112+1 LSA/ 111 ICL 0>IVO 42>IVC 47>EVO 1>EVC 113>ECL 1* overlap
Fracker 223/228 .603CMo/.586CMo 112+.5 LSA/ 111.5 0>IVO 43>IVC 46.5>EVO 1.5>EVC 112.5 1.5* overlap

Twister 223/230 .595CMo/.578CMo 112.5 LSA/ 111.5 0>IVO 43>IVC 48.5>EVO 1.5>EVC 113.5 1.5* overlap

lil duece 224/228 .603CMo/.587CMo 112+1 LSA/ 111 ICL 1>IVO 43>IVC 47>EVO 1>EVC 113>ECL 2* overlap
HalfSpec 223/229 .603CMo/.587CMo 112+.5 LSA/ 111.5 0>IVO 43>IVC 47>EVO 2>EVC 112.5 2* overlap
MiniPred 223/231 .610LSL/.598HUC 112.5 LSA/ 111 ICL 0.5>IVO 42.5>IVC 49.5>EVO 1.5>EVC 114>ECL 2* overlap
lil Motion 225/229 .603CMo/.587CM0 112+1 LSA/ 111 ICL 1.5>IVO 43.5>IVC 47.5>EVO 1.>EVC113>ECL 3* overlap
lil demon 226/228 .605LXL/.571XE 112+2 LSA/ 110 ICL 3>IVO 43>IVC 48>EVO 0>EVC 114>ECL 3* overlap
lil devil 224/230 .612LSL/.571RPR 112+1 LSA/ 111 ICL 1>IVO 43>IVC 48>EVO 2>EVC 113>ECL 3* overlap
Mini Torro 226/230 .600XFI/,573XE 112+1 LSA/ 111 ICL 2>IVO 44>IVC 48>EVO 2>EVC 113>ECL 4* overlap
P-Z 243 224/234 .609XFI/.605XFI 112+2 LSA/ 110 ICL 2>IVO 42>IVC 51>EVO 3>EVC 114>ECL 5* overlap
Toro Motion 230/230 .355CMo/.603CMo 112+3 LSA/ 109 ICL 6>IVO 44>IVC 50>EVO 0>EVC 115>ECL 6* overlap
6 pack 226/230 .612CMo/.595CMo 111+1 LSA/ 110 ICL 3>IVO 43>IVC 47>EVO 3>EVC 112>ECL 6* overlap
(I bet that didn't format right, nope) I believe I want to go with the one I names the Twister. I think if I ask for a 223 on a 111 ICL and 230 on a 114 ECL the initial timing chain stretch will get me there.
The question I have for you all is will this cam give me what I want ? My driving habits have not changed. This is not a drag racer. It's a DD / canyon carver. 46 miles round trip for work with 10 miles of it on the sweetest twisty piece of asphalt you've ever seen.

whatsa347

iTrader: (6)

I don't have anything to add, but LS FD's are the ******* ****. Also, I've often wondered if people with lighter cars can go with bigger cams because they don't need as much torque to get going, or if it's the opposite that because they're so light they don't need a big cam to be quick.

squalor

iTrader: (3)

I have a LS6 cam in it now, not sure which one, but it's like a theme park ride. Here is a pic of my exhaust before welding and paint. It has a ladder bar going to the M6, a bad way to support the diff because launching is hard. Bad wheelhop. I have to get it rolling and then pour into it. Because it's light, when it bucks, it bucks bad. I might try to chassis mount the bar after the engine work or buy the Samberg diff mount.
I'm hoping for the latter. A 223/230 112.5+1 is not a big cam, softer than what Pred-Z suggested. I think he was saying to use XE-R lobes but EPS has a 224/230 111 called the truck torque 3. I think the advance is +2. I just think the one I came up with would have better off-idle torque but still be able to carry rpm up to 6800.

crozhuyou

What is a common grind that is close to your recommendation ?

Exidous

iTrader: (11)

Camming an RX-7 is just like any other. Bigger cam means more power. However, the lighter weight means less cam needed for a given goal compared to a heavier car. (obviously)

When I had an all stock LS1 and iron manifolds on shitty sumitomo 225 tires I pulled a 12.1 in the 1/4 with a 2.0 60ft. The only thing stock left in my motor is the short block and I'm running a "baby" cam. 225/227ish. I've not had the car to the track since but I can promise on good tires it's a VERY low 11 car. Certainly enough to get kicked out. No cage.

As you are after good lower to mid tq and some mpg I'd stick to the mid 220's on the cam. That's exactly what I was after. Something like my cam would work well. 225/227 LSL lobes on a 114+3. Mine was specced for the Mamo 220 heads which are a huge difference from stock 243's. However the AFR's like low split(great exh port). The stock heads and stock port would probably benefit from a little more exhaust duration. Like 225/229. Either way, you should talk to a pro about cam spec. Just make sure you are absolutely clear about what you want out of the car. I've found if you are a little vague the cam guru's will usually spec a little bigger.

With that much DD you'll want smaller. Maybe even in the high teens to low 220's. Later on you can throw on some used AFR 205's(~1600) and up the CR. Will be a very fun car. The only thing the smaller cam will cost you is peak power and a little mid range. But there are big benefits to the low end. Incase you have not noticed, I don't like big lumpy idles and poor off idle acceleration. :-) I like between -4* and 0* overlap.

usdmholden

Light car with a low rear gear can get away with a bigger cam. It will respond just like any other car if a baby cam is used, but a light car will spin tires more often than a heavy car.

ahritchie

iTrader: (1)

Exactly.....I'd IMO put a bigger cam in it, it would have more character like the original rotary....a higher RPM screamer that still make double the torque of the wee little rotary regardless of the bigger cam. Those 4.10's and light weight don't need high tq to get moving fast unless you just want to burn tires, too much torque can make it harder to launch....needs HP and high RPM!

squalor

iTrader: (3)

Exidous, usdmholden , I remember you guys from norotors. Thanx for your opinions. " I don't like big lumpy idles and poor off idle acceleration. :-) ", I feel the same way. If I'm in a turn a little hot I want to know the power will be linear and predictable. I want throttle response across a wide rpm band. Not really concerned about what the dyno says.
I should say that the 243's will not be stock. I intend to size the bowls and thin the guide boss. Probably leave the rocker boss and shoot for 210 /215 cc . Probably do more work on the exhaust side. Un-shroud the chambers. Then send them to TEA for a valve job and mill. I need to settle on a cam before TEA does my heads so I know how much to have them mill.
crozhuyou , the EPS truck torque 3 or the Tick sns1 would fall above and below my idea.
ahritchie, what would you put in if this was your car ?

dr_whigham

iTrader: (49)

I'd put a StreetSweeper HT... But that's me

Darth_V8r

iTrader: (4)

Squalor, check out the Titan 3 at cam motion. 224/228 113+4. Has exactly zero degrees overlap. on 243 heads with 040 cometics, DCR (if that matters to you) would be about 8.4 Valve Events at 050:

IVO - 3 BTDC
IVC - 41 ABDC
EVO - 51 BBDC
EVC - 3 BTDC

Effectively, this would carry power a bit better than a comp XER273 (-1 overlap at 050 vs zero), but the lobes are gentler, so the 918's are fine - even at 0.610 lift. This should get you killer power under the curve, have good initial torque (41 IVC), not too lumpy on the idle, will still rev nicely. Should be a very well-balanced cam and make for a daily driveable, very fun ride.

To be honest, with your gears and headers, I would suggest going into the higher 220's on intake and the low 230's on exhaust. For example, the Titan 4 at 227/232 113+4. Still only has 3.5 degrees overlap at 050, and IVC is "delayed" to 42.5, so still good torque, but will have a slightly higher rpm range, which could better match your gears and would definitely rev to 6800.

squalor

iTrader: (3)

The HT is a great street/strip cam but with my beehives, I think I would need a smoother lobe to get the reliability I want. With all the spintron testing done on the LSL and LXL lobes, I think they are close to the best on the market. If only Comp's manufacturing was as good.
I'm going to try to get Cam Motion to grind with a .006 to .050 difference of 53. My hollow valves and PSI's should be happy with that for a long time, maybe 50K before they go soft. Also, I want to be under .600 lift.

squalor

iTrader: (3)

I already have SCE .041 graphite head gaskets and PSI 1511ml beehives. I do want a Cam Motion cam and plan to order through Colorado Speed.
Have you ever read the "Torque coming out of My Ears" thread ? PatG had a 224/228 110+0 cam that pulled to 7k without dropping off. EVO > 44
What I got from the post was there are 2 ways to get a cam to carry rpm. Spill exhaust early with a EVO of 50 or more and loose some low rpm torque or place your overlap center after TDC. PZ's suggestion was 2/42/47/3 so it followed that example. My idea is 0/43/48.5/1.5 for more off-idle TQ and less chop, better throttle response. The trade-off is my intake valve is not at a high lift point when the piston starts CFM demand. I considered going the other way, see the cam I named the Toro Motion. It would limit how much I can mill but work with a quiet exhaust.
I appreciate all of your replies, please keep them coming. There is always more for me to learn.

Darth_V8r

iTrader: (4)

I STUDIED that thread. I still don't understand some of the discussion on it. I wanted to try a cam like that at one point, but backed out, because I daily drive, and springs would have been an issue on that cam.

I suggest you call Kip direct if you haven't. He's a cool guy to talk to.

squalor

iTrader: (3)

I studied it too and shook my head alot. LSK lobes on LS7 lifters and 5/16 pushrods. 2/42/44/4 were the events. I don't think it was the huge lift that let it carry but the fact it had 4 degrees of overlap after TDC. I think he did break a spring.
I have never called anyone without buying something. The only pro I asked for a cam spec was Brian Tooley. I bought over $300 but he never replied to the Email. When someone asks me who spec'd my cam, It would feel good to say, "I did". (with a little help from my friends) If I were going to ask a pro to crunch my numbers and spec the perfect cam for me, it would be Martin Smallwood. I've learned so much from reading that guy.

Darth_V8r

iTrader: (4)

Martin has done quite a lot for LS1Tech community to be sure. It might be worth noting that Pat G tends to spec EPS (endurance) lobes now more often than not. I only mention it, because for a while I fell prey to the thinking that "more faster ramp rates means a more better cam", and I've come around the other direction now to thinking that it is best to pick the lobes you want for your driving habits first and then look at the 050 valve events. And you seem to be taking that approach.

And you've done a pretty good job at picking up on the theory. I still struggle with the IVO and EVC events and how they affect power (other than creating overlap - or not), and why intake biased vs exhaust biased overlap makes a difference.

Another cam to throw at you for consideration - Cam Motion LS1 stage 4 drop-in cam. 228/232 114+4 at .550/.540 lift. You could install that with LS6 springs. Pretty close to that Toro Motion and designed for higher gears in the rear. IVO=4 BTDC, IVO=44 ABDC, EVO=54BBDC, EVC=2BTDC. 2 degrees overlap. That should make some good power and be easy on the valves.

squalor

iTrader: (3)

It sounds a lot like your cam. Your thinking about changing, what's your favorite spec for your application ?