TU and F4 Camshaft Follow-on Discussion

[moparzrule]

I thought he had them sent out and done? Or are you saying he gave them that ratio to use?

No he converted that part himself, they only gave him the lobe lift specs. Must have been .001 different than Todd came up with, which is reasonable instrumentation error.

[4 l-bodies]

Ya know I just thought of that after typing my post.

It would surprise me if Todd didn't already have the stock roller done

Although I have ran many camshafts on Cam-Pro machines, I only have installed specs for stock 89 turbo roller from .006 through .050 lift. Wanted to find true valve event #'s at common .050 lift figure. I certainly could run one, but as you know it takes some time to do.
Todd

[4 l-bodies]

I believe chris used 1.78 rocker ratio to figure the actual lift, not 1.75 which Todd is what used to come up with that figure. The lobe lift spec he has was every so slightly different, Todd's specs with 1.78 ratio would give it .498/.509 lift.

I thought he had them sent out and done? Or are you saying he gave them that ratio to use?

No he converted that part himself, they only gave him the lobe lift specs. Must have been .001 different than Todd came up with, which is reasonable instrumentation error.

That is 100% correct. Machining and instrumentation variances can and do happen for sure. The Cam-Pro uses its own follower but you can input a follower ratio in Cam-Pro. 1.75:1 is typical for new aftermarket followers. Mopar used at least two different vendors for the followers. I have measured both 1.75 and 1.77 at some point in time over the years. A used worn follower is usually going to be a bit shy of these marks though. My measurements were at both lobe and at valve retainer. I purposely verify that I am seeing calculated valve lift from lobe lift, at actual valve lift. That lets me know that dial indicator axis is correct and that I am parallel to valve and perpendicular to camshaft, and of course that my follower ratio is correct. You can very easily scrub off some valve lift (which in turn effects actual measured duration) if end of dial indicator is walking around the retainer as it follows valve opening and closing events. That is what takes so long to set up when degreeing these camshafts in.
Todd

[4 l-bodies]

I have second TU camshaft #'s to post. TU's R4+. I measured valve events only through .875" valve lift. Smaller duration than the R5 and F4 and tighter LSA at 112. Lift just under .500 on both intake and exhaust. Contact Chris @ TU to learn more.
Todd

[moparzrule]

Thanks for all your hard work so we can get the true specs!

[twon1977]

All great info. We all appreciate the work put in. Seems like this debate will go on. I have a question and I hope I'm not hijacking. I'm new. My question is, these cams being talked about, can anyone give an ideal rpm range for each. Very general, I understand every build is different but assuming anybody looking at this thread has the general mods needed to support these cams, big valve ported head, ported 2 pc intake, big turbo, supporting electronics ect. Where is the f4 being shifted at? Rpm. How would any of these cams behave in a 2.5. I'm building a 2.5 with all the good stuff. Steve m big valve head ect. I know the 2.5 wont rev much. I appreciate any cam advice. Thanks

[GLHNSLHT2]

bahh won't rev. A built right 2.5 revs just fine.

[bakes]

^

[acannell]

theres a debate? where?

[Shadow]

The F4 makes peak power on a properly built 2.2 between 65-6700RPM depending on specific components. We are installing F4 cams in two 2.5 builds that are going on at the shop right now and I would expect peak power to come in right around 57-5900rpm with a powerband (actual shift point) of just over 6000rpm.

I shift the Charger at 7000+RPM at the track with the F4 cam.

[4 l-bodies]

All great info. We all appreciate the work put in. Seems like this debate will go on. I have a question and I hope I'm not hijacking. I'm new. My question is, these cams being talked about, can anyone give an ideal rpm range for each. Very general, I understand every build is different but assuming anybody looking at this thread has the general mods needed to support these cams, big valve ported head, ported 2 pc intake, big turbo, supporting electronics ect. Where is the f4 being shifted at? Rpm. How would any of these cams behave in a 2.5. I'm building a 2.5 with all the good stuff. Steve m big valve head ect. I know the 2.5 wont rev much. I appreciate any cam advice. Thanks

Welcome to the forum! Good to have new people here. Many people are shifting their F4 cams in 2.2's nearing 7K or maybe slightly past. The R5 is too new to the market for any feedback on RPM powerband, but I believe it will be similar. Obviously any substantially larger duration camshaft than our stock camshaft is going to lose some low end torque. Anybody that tells you differently is well... you know (haha).

Many years ago some chassis dyno tests were done on a well built 2.2. They were testing the predecessors to the F4 and R5. A similar camshaft to the F4 (Taft S3) lost 30 lb-ft torque below 4000 RPM, approached stock around 4500 RPM, and after that demolished the stock torque. In the end the camshaft gained like 60 HP in this application over stock at redline (6700 RPM)! Note this was on a very aggressive engine with lots of supporting mods. This engine was obviously begging for more camshaft than the stock one.

I recently installed a slightly smaller duration camshaft than the R5 and F4 in a very well built 2.2 turbo in L-body and it had a very nice broad powerband. It was still pulling up to 7K when I backed out of throttle. It had about 4-5° less duration on intake and exhaust @.050 than the new R5. Also a bit less overlap too. Idled smooth too at 19 HG with just a hint of hesitation as throttle was first opened. Lift and LSA was close to the R5. It was a very streetable camshaft in a 2.2. In the end I thought I could have even gone a bit more aggressive on the camshaft had something slightly bigger been readily available. I am now building another 2.2 engine with a few more mods and plan on trying both the F4 and R5. I should note I tend to error on the side of conservatism when it comes to camshaft and turbo selection. I just hope the additional duration and overlap won't be too big of hit on mileage and off boost driveability. I will gladly trade some ultimate high HP #'s for broad powerband with good street manners, valvetrain durability, and that won't kill big mileage in the process. My reasoning is because most of these vehicles are dual purpose at best. If I was building a track car only, it sure wouldn't be a FWD 8V 4 cylinder!

I think your question on RPM powerband is a good one esp. when using a 2.5. Bolt on too big of turbo and too big of camshaft and your 2.5 could have a very narrow powerband due to the far less than ideal rod ratio of the 2.5. With that said as a general rule, the bigger the engine the smaller the cam will act. Rob (Shadow) is building a 2.5 currently I believe for a customer. I believe he is planning on using a F4. My advice is when in doubt or having to choose between two candidates, pick the smaller camshaft or turbo for a vehicle used primarily on the street.
Todd

[Shadow]

All great info. We all appreciate the work put in. Seems like this debate will go on.

Agreed, I think it's good that all of this came out, but it really only Proves the F4 and why it works as well as it does. Without the Experience of Knowing what our heads Need as far as cams go, you are only taking a Guess, and that's Exactly what the R5 cam looks like.

Whoever designed that cam obviously believed that the Exhaust side is what Needs Help, so it is "backwards" engineered AFAICS. Anyone who knows anything will see that the efforts made on the exhaust side of that cam will be wasted. (no significant gains)

So the only attraction is the slightly higher intake lift and Faster valve opening, but Less duration.(Tighter LSA could have been interesting, but even that was quite a ways off from advertised and Very close to the F4)

The F4 is a much Better Balanced cam, and I think it will out perform the R5 in all but the strangest of build combo's. Having said that, it could be a wash and both cams found to be very close to equal? Really hard to say until someone actually shows some real results!

[Shadow]

I am now building another 2.2 engine with a few more mods and plan on trying both the F4 and R5. I should note I tend to error on the side of conservatism when it comes to camshaft and turbo selection. I just hope the additional duration and overlap won't be too big of hit on mileage on off boost driveability. I will gladly trade some ultimate high HP #'s for broad powerband with good street manners, valvetrain durability, and that won't kill all mileage in the process.
Todd

Will be interesting to hear the results of a BtB on those two cams for sure!

I was actually more surprised by the R4+, a Better balanced cam than the R5 and much tighter LSA! Looks like a cam that would make good power albeit @ lower RPM than the F4 but the TQ curve Could be interesting.

[bakes]

i want to ask a question looking at from another angle which cam should perform better with high high +30 boost levels ?

[moparzrule]

It's unknown at this point.

I have the R4+ as well to test out, but right now my daytona is buried under a bunch of snow

[4 l-bodies]

So does anyone have a Taft S3 they want #'s ran on? I'll do all the timing events for pro bono if someone wants to send one to me so we have data on that too. BTW- No damage to camshaft will take place. Engine is not run during this procedure.
LMK,
Todd

[acannell]

this is shaping up to be really great as far as getting data together..thank you Todd!!

we should probably also collect known data about how cams ran/dynoed..even if its from ancient threads...

[twon1977]

Thanks for the great info 4 l bodies and everyone else. It seems well have to wait till spring for alot of real world testing info to come out. I have a nice build going on now consisting of 2.5, steve m head, 3076r turbo, tu header, bmf intake, fast xfi ecu, 568 with 3.50 fd. I'm hoping to put down some good power, maybe 400+. I'm thinking maybe a r4+ would be ideal on a 2.5 and a f4-r5 for 2.2. Assuming their both fully built. I'm thinking piston speed limits the 2.5? Once I get it going this spring I will certainly share my findings

[chilort]

For those who have installed these cams, considering they are both ground by Colt, how has the centerline been working out?

[4 l-bodies]

For those who have installed these cams, considering they are both ground by Colt, how has the centerline been working out?

Not sure where it was revealed that both cams were ground by Colt? However looking at the #'s I'd say both are going to be between 110-115 intake centerline will be the sweet spot. I recommended 112 to someone privately for starters for the F4. I would surmise that not many have degreed them in, that is why no one is answering your question. IIRC Rob had his F4 installed at 115. I think Warren said when he ran one it was advanced a bit more than that. That is not to say that they will be even remotely close if you just install them without degreeing them in. The F4 I degreed in was ground pretty retarded. The R5 less retarded but still retarded a bit compared to it's LSA. Hope this info helps. The R4+ appears to be ground WAY retarded.
Todd