NoTread

Hello. After researching specific cams & how cams work for quite a while now, I have decided on the cam I want(unless someone somehow converts me) & that is obviously the Trex(thus the title). But first I have some questions:

1) How come the Trex cam is made for stock heads? Wouldn't it be SEVERELY underflowed on a completely stock lsx head? So how does it make such great power; even though, theoretically, it shouldn't be able to make that power w/o great cfm #'s(which the stock lsx head obviously doesn't have) - Feel free to correct me, as I am limited by ignorance. And what kind of #'s is the Trex putting down in a4's?

2) Combined q's: 2a) The Trex needs high revs. for it's max. power range, so how high should I rev. it safely(of course w/ all aftermarket head equipment installed)? 2b) With the set rev. limit from 2a, how long should my stock bottom end last if I replace certain internals at set yearly intervals on an daily driven a4 w/ 4.10's & a 4400 stall? 2c) What will need to be changed(directed towards the end of q 2b) & how often?

3) Are there any other additional parts that I will need to change out besides those listed above & how often?

Thanks guys for you time & patience. Feel free to enlighten me(& bash my thinking) in any way possible.

orangeapeel

iTrader: (18)

2b) When you say internals... I bet you are referencing to double valve springs?

2a) And it will be more than a stock bottom end can support in most cases. I think safely you could do 6700 or maybe 6800 since you are an A4 and wont be missing shifts like an M6. Probably 4.10's at the highest. Maybe 4.56. and that is a good stall for that cam, considering it really suggests one.

2c) You might want to think about a 12 bolt or 9' if you havent already done so. cause by the sound of it, you are going to be dropping the hammer more or less.

Hope this helps, someone else can probably be more thorough where I beat around the bush on details.

lessmoneymoreHP

What is the basecircle of the T-Rex anyway?

NoTread

Thanks orange for your input. Yes, I am refering to retainers, lifters, valve springs & such. Also, my car is a CORVETTE C5, not an f-body... I can't believe I didn't mention that(It was really late in my defence). So, the fact that I have a different transmission than an f-body , will that effect any of my questions any differently? Sorry bout that... Any additional input?

smithsc

In regards to what you can expect, I have the Trex cam in a 2002 Z06. It's been in a little over a year with maybe 10,000 miles.

You can see my mods in my sig, but it dyno'd 451rwhp and 396rwtq. I had the rev. limiter changed to 6800rpms to try and take advantage of the entire power band. It really hits above 4000-4500.

The sound at idle (especially without cats) is absolutely AWESOME!!!


Steve

nokeman

iTrader: (30)

just a quick question for you smith...sorry to jack your thread notread. you have put 10000 mils on the trex...how is it driving daily...and how was the idle before a tune. i am seriously thinking of installing the trex because those numbers are just amazing.

NoTread

Smith - Good to hear & nice #'s. Also, I don't have any cats either... but then again I also DO have headers & SLP Loudmouths(Straightpipes)... God bless the neighboors

So, can anyone take a shot at question 1? I know there are some techies on here that know the answer. Also, I want to raise the litmiter to 7,200, as I believe that would be the best(feel free to set me straight if anyone thinks otherwise), since this cams range is from 3500-6700, & I believe it will still be pulling even harder, the higher the rev. Plus, I care mostly about how the car performs from a roll, so I want max. acceleration, so I am going w/ 4.10's, but people say it will run out of steam too fast. Well, perphaps it will(Or not? In a C5), but if the limit is set at 7,200, then at 130 that would be equivalent to a 3.15 gear at it's STOCK redline, going into 3rd. So, it's like killing 2 birds w/ 1 stone. Any thoughts on this?

Lady Redhawk

iTrader: (6)

You have essentially the same transmission that an F-body has (4L60), it is just in a different place. There is however a big difference in the rear-ends, but a 12 bolt is still something to think about getting for it.

NoTread

Good to know Lady RH, thanks. I'll keep that in mind. Anyone else?

Lady Redhawk

iTrader: (6)

P to V clearance is pretty tight. So unless you have valve relief cut on your pistons, completely stock unmilled heads with stock gaskets is the safest. There are now some after market heads that might work fine with the T-Rex, like possibly AFR 205. It isn't a question of whether the T-Rex could make better power with heads, you just have to be sure your valve don't kiss the piston
No reason to shift any higher than 6750 rpms with that cam. That will keep you in the power band as you shift as long as you have a good tune for your transmission. You will want to change your valve springs every 15,000 miles

Get Dual Valve springs and spring kit, push rods, You will want to change your valve springs every 15,000 miles

calongo_SS

iTrader: (7)

The people running this cam for real at the track are getting the best times shifting at 7000 - 7200 rpms. Go with some Katech or ARP rod bolts and you should be fine.

NoTread

Lady RH, excellent reply. I have heard of ppl running 5.3heads & 6.0 head, AFR 205's & 225's, & some others. It seems like the most power would come from an AFR 225 combo, BUT... I am not sure what would be required to do this &/or if it would be safe to run an 11:1 compression head w/ this cam & an 150 shot...

Calongo, thanks for your input, that input might help me out when I do the tune. Also, I have looked at other's dyno charts & the pull stays nearly the same past it's peak at 6700+. Also, some setups(same stock heads though) are peaking around 7,000, which makes me wonder even more where I should set it, since it seems the peak fluctuates.

Also, like I said, I am still worried about the gears not pulling hard enough at the top of 2nd & beginning of 3rd(since they are so tall)... Any more opinions?

orangeapeel

iTrader: (18)

I believe that you would be right up in the big power mark with that...But it would be pretty risky too with the nitrous. But you are an A4 so it shouldnt be too big of an issue.

But, do understand that you will most likely be wanting to do the above rod bolt upgrade....Better saf(er) than sorry. especially if you are going to spray it.

orangeapeel

iTrader: (18)

If anyone knows, Im no expert on the T-Rex, but do have almost identical results from my cam. The powerband might extend a little past 6700 realistically, but whenever it hits its peak it will most likely fall off...and pretty hard at that.
Can anyone else lay any truth to that?

alans02z

iTrader: (9)

I have the trex cam, drive it often. Its drivable and decently smooth after about 1700 rpm. It can only get better after Lady redhawk dyno tunes it for me.

NoTread

Didn't realize this thread was still alive, so I hadn't checked it in a while.

Orange: Thanks for the comments. Yeah, I will certainly be looking into rod bolts. As for the power drop... well, I also am no expert(obviously), but from some dynos I have noticed hp barely decrease(if even at all), after you hit it's peak, but torque, on the other hand, does drop & hard. That has to be a run-on sentence...

Alan: Thanks for the input & good luck w/ that tune. I'm sure she'll do a fine job.

SouthFL.02.SS

I've known 2 Trex cam users that have had dual springs fail. Make sure you get Comp 921's or Patriot Gold duals. Check/swap them out every 12-15K as mentioned above.

LIL SS

iTrader: (9)

Hmmm, seems to me every Stock Head Trex cam car I have seen peaks about 6300-6400rpm.

At any rate, Question 1) Think about this a second. A Stock LS1 head stalls about .550 lift right? Well how long is the valve open more than .550? The Trex only lifts to .608, I imagine the time spent from .550-.608 is very little. Even from the .550-.608, your still getting air in to the cyls, just not at the same rate.

The key here is you are getting more air in the cyl's from .006 to .550 with this cam then say a 224, 230, 236 ect. More air in the cyl, generaly means more power.


On to your short block. It is not going to live long shifting a 6800 let alone 7200 with out some upgrades. Rod bolts are key, but since your there, mine as well put some rods and pistons with valve reliefs in it too since to motor will be out. With the potential P/V issues, it's better to be safe. As valve springs start weakening you have a much greater chance taking things out in your short block.


Another thing I don't see mentioned is lifters. Sure the stockers will work, but for how long? A Colapsed lifter sucks as you have to pull a head off the car.

NoTread

Thanks SouthFl, I will be looking for those you mentioned.

Lil SS: I'll relook over those dynos then, b/c I could be wrong. I am sure I saw them peaking at around 6700+, but perphaps they could have aftermarket heads. Thanks for the answer to #1. You'll have to excuse my lack of knowledge, I just recently got cams down, now I am buisy trying to learn about heads. Also, I will be changing everything you mentioned w/ the exception of the pistons & valve reliefs(not enoight money at this time), also possibly not the lifters. How long should the lifters last? If long enough, I'll just wait to change them when I change the dual valve springs 15,000 miles down the road. Thanks for all the info.

LIL SS

iTrader: (9)

No telling how long the lifters will last. Remember, more RPM's takes it's toll on things. Spring pressure will kill the lifters faster than the RPM but the 2 of them together will kill them faster.

My feeling on things is do it right the first time. If you can't affor the good springs and the good lifters, wait. Hell you have to pull the heads off to do the lifters, get your stock pistons fly cut if your not going to put aftermarket ones in. You never know what might happen.