Need cam advice as soon as possible

[turboglenn]

As i said in my other thread i ordered 264/272 cam combo today, now I'm 2nd guessing myself. Should i have just gotten the 272/272

My main 2 things are

1.) How much difference is there in the spool of a larger turbo like a 57 trim t3/4 with a stage III turbine?

2.) How much low end torque difference is there?

I just don't want to give up a better top end improvement for a very minimal low end and spool improvement.

I'm trying to get somewhere in between 400-450 (realisticly hoping for 420'ish) daily driven horses with no more loss in bottom end or problems with the cooling system to remain as reliable as possible so i don't mind giving up a little top end if it's made up for in other areas.

If i get an answer tonight i can email before he ships tomorrow.

I've ridden in several cars with 272/272 and even 280's but never the 264/272 combo, and i loved the way those sets of cams seemed to run, but it's hard to tell since most people have such different turbo setups and everything else you can't pinpoint what was actually the cam. That's part of why i wanted to try it, i always try and be a little off from what every one else is doing for the sake of doing my own things and testing other combos.

BTW...I did search, just didn't find answers for them. Most of the threads turned into arguments about what name brand cam is junk or if a stroker motor was better or not and how long they lasted, nothing about spool and low end power

 

[turboglenn]

I just realized when i came back to check for replies that this is in the wrong area. Feel fre to move it if need be mods and admins, sorry!

 

[90laserRSfwd]

depends how you dial the cams in and what kind of tune you set up. I mean obviously the over lap and lift car different for the 264 vs. the 272 cam but if you degree the cams and set up a decent tune you can get the 272/272 combo to make more torque then the 264/272 setup. It's really based on the setup. There is a pretty reasonable difference I'd say between the 264 and 272 cams. The haltech is a good stand alone and I don't see you having too much of a problem getting a respectable tune. I'm not so sure though that the 8:1 pistons are going to help much with the off boost power. Your profile doesn't list very many mods for me to judge what exactly to recommend to you. I'd say try to add some timing pre boost and see what you can make of it. As for the cam choice. I'd say just go with the full 272 set up and get a good set of cam gears (like HKS's or AEM's). Just my 2 cents though. I'm not John Shepard......

 

[turboglenn]

Thanks, that's exactly the kind of input i was hoping for. Do you know anything about the spool characteristics of the 264 over 272?

Also, besides the supporting mods to be where I'm at now, i can't think of much more to list. The one time we pushed my last motor to the limit we hit 468 on 118 octane and about 28-29 psi, there's not too much of a difference in the 2 setups besides the other bottom end was much stronger and the head was ported but it still had stock 1g cams and a few other small goodies i had to sell off when that moor ended up being machined wrong and i needed cash for a short-block fast. People have said that the dyno we were on in KC that day was very "optimistic" though, so it was probably a little less true HP.

 

[90laserRSfwd]

Some how I completely went off the deep end there and didn't answer your questions, ok so here goes...

?1 > If your trying to ask how much of a difference there would be in spool time with the 272 vs 264, I'd say nothing that is going to make you choose one cam over the other. A turbo that size is going to spool, in my opinion, within 50 rpm's with the cams, probably not even that much.

?2> The torque difference can be setup with the tune, the 272 has a little more lift so I'd say you could get just a bit more with the 272 but it would be at a higher RPM then the 264 (again nothing to make you wanna really choose 1 cam over the other).

I'd say for the average person, no offense towards you, that adding cams seems to be described as a "turning the boost up" kind of feeling. I personally would recommend the 272/272 combo, but I like to over build things so don't take my word as gospel here. At the point where other members start adding cams there isn't really going to be much, if any, comparison of the 264/272 vs the 272/272 setup. Because the difference between the 2 setups is so close, many choose to just not go from the 264/272 to the 272/272. Sorry I'm writing a novel here, I just want to try and give you as much information as possible for you to make your decision.

 

[90laserRSfwd]

PM sent

 

[turboglenn]

Well, i'm looking for the most low end and browdest torque curve i can get with the fastest spool possible. Even with the 264 when i get gears (again) I'll still porbably degree it for more spool. i'm even sending the tubo off to have a smaller turbine and hot housing put on it this summer when i have a spare T-3 to throw on it while mine is off being rebuilt, i'll porbabl tet/thrash one of those ebay jobs and just put a screen in one of m IC pipes to catch impeller blades if they fly off (j/k about the screen)

 

[90laserRSfwd]

I was recommending the 272 because I see that your car is fwd. It's really up to you which you decide, since there's always room to improve. I don't think you'd notice much of a difference in bottum end pull. It's really more about the tune. Comparing the 264/272 combo to the 272/272 combo is kind of like comparing a 35psi boost gauge to a 40 psi boost gauge, they both do the same thing, one just does it better up top... Not sure if that's a good comparison... Probably NOT

 

[turboglenn]

I'm only revving to about 7500..the power falls off now at about 6200 or so, but i'll rev it out to 7500 when needed. I really would like the car to pull hard all the way to 7500, That would be perfect, i dont' need every last bit of power, i just want it to pull hard all the way to redline. I'm not looking for any more RPM than that simply because of the tranny and it not likeing to shift past 7k anyway. And i am definately not going so far as to order a shep or jacks tranny for it unless it's a plain rebuild with an LSD. after this my plans are the plain trans rebuild, finish the suspension and interior and have it painted and call it done!

 

[kahl23]

All I can speak to is that when I dyno'd my car over the winter with a 16g (3052 is now waiting to go on ) I got around 15lb-ft more than horsepower, i.e. 374awhp and 389lb-ft. This is on a 264/272 setup. That being said, its a smaller turbo than what you're running, YMMV.

 

[Jst4Cyl]

If you're a member of the DSMLink boards there is some good info on there. 280's have been proven to make more power and have a larger (or at least a higher power band) power band than the 272's. You lose some low end grunt but gain it up top. I guess it is like a stock intake vs. a Magnus. I'm ok with lag and the loss of torque as long as I go somewhere when boost comes on
This isn't the only back to back dyno results of the 264's vs. 272's vs. 280's .

Here is a link to BC's site , there is a dyno graph of the 272's with: T3 turbo (22 psi), BC0100 spring/retainer kit, 4" intake, 38mm ext wastegate, 3" downpipe, RC 850cc, race gas.

And the 280's with: T3 turbo (18 psi), BC0100 spring/retainer kit, 4" intake, 35mm wastegate, 3" downpipe, 93 octane pump gas

I'm unsure if this was on the same car as I doubt it was being that one mentions the inj and a 38mm WG, and the other says that it is a 35mm WG and fails to mention inj. Either way the 280's produced more power on less boost and on pump gas. Is there anything more to ask for? And I do realize that you want the fastest spool but maybe this will actually aid in giving you the extra few mph before the power band.

BTW, nice numbers Kahl23

 

[blcknspo0ln]

I'm only revving to about 7500..the power falls off now at about 6200 or so, but i'll rev it out to 7500 when needed. I really would like the car to pull hard all the way to 7500, That would be perfect, i dont' need every last bit of power, i just want it to pull hard all the way to redline. I'm not looking for any more RPM than that simply because of the tranny and it not likeing to shift past 7k anyway. And i am definately not going so far as to order a shep or jacks tranny for it unless it's a plain rebuild with an LSD. after this my plans are the plain trans rebuild, finish the suspension and interior and have it painted and call it done!

IMO: turbo, cams, and intake manifold are your restrictions if you don't want to flat line up top. It's pretty conclusive that if this is your goal you're going to have to make some sort of compromise. Don't worry though, Although the auto world has been moving towards 'bigger and better' equipment, the 264/272 has long since been a favorite for those that desire exactly what you want. This combo is going to give you nice street grunt with the ability to flow to 8k if you so choose (and support) it. IMO your decision has been an educated one, although having the 'I should have gotten the 272's or 280's' will always loom over your head and it's not worth it to dwell over it. As for your tranny, is it not healthy? I spin my stock 130k mile tranny to 8.5k all the time. As long as I'm not using no-lift-to-shift, she shifts like butter, otherwise a little grind comes out of it. I don't think spinnign a stock trans past 7k is a bad thing, though.

 

[turboglenn]

Blckspo0ln.. You gave me the answers i was looking for. My tranny is fine, just DSM tranies in general don't shift as well as other OEM transmissions do at higher RPM's and the cable shift doesn't help for positive and quik gear changes. It's in great shape according to all tests ( i can go into first at 20 MPH fairly easy and all measuring checkes were within spec)

I feel confident in my choice in cams and since i'd rather have a broader power band than a narrow completely high RPM one, i think i'll be happy. Then i need to send the intake mani off for extrude honing :woot

As long as it will pull strong to 7500 and still perform decently down low where i spend 70-80% of my driving i'll be just fine.

Thanks again everyone on the help..hopefully i'll have dyno sheets up in a week or 2.

 

[dsm-onster]

Glenn, yes, Tom is right. You have the cams you need for what you want. If you feel like you want more later, you only have one cam to buy . But not likely. . . The feel you give for your goal suggests that you want a little overlap and a reason to say in it after 6500rpms. The cams you have ordered fit the bill IDEALLY. Good choice!

One can alter the rpm torque peak and spool of 272s simply by retarding the exhaust cam a few degrees (dialing in more overlap). But enough overlap to yield the "flatter" powerband of 264s will destroy idle friendliness. Considering that a certain duration is ideal for a certain aircharge velocity, a lower duration is reqired for the results of 264s. 272s arn't bad on the street IMHO. I adored my t3 stage3 and fp2s on the street. It took ample self-control. But, 264/272s give you better idle, and will "pump out" at least the exhaust gases better than 264s. Which is very important to maintaining VE to redline and what you're really after. Considering we have faster air velocity than n/a systems, we can get away with not using as much airmass momentum on the intake side to get good cylinder filling. This is why 264 duration intake cams don't kill power up top all too much and work well with 272 exhaust cams.

Consider one 272 intake cam a good upgrade down the road, though. The fp2/fp2x/hks272 cam (and any other 272 cam designed similarly) has an effective valve closing angle that matches a 1G/2G intake runner length at the third harmonic at 4500rpms. The third harmonic seams to be the design goal of Mistu with the stock cams and intake manifold at 6Krpms. Interestingly, the SECOND harmonic is matched right at 7000rpms with 272s. This is also where momentum of the aircharge works best with the duration of 272s. The engine will feel a little more peaky, but would pull VERY much harder at that point with a stock intake manifold if it wern't for that tiny plenum .

Regardless, you'll be very happy, if you've been pushing air through the stock 2g cams for any length of time.

 

[kawboy]

So whats the vote? Combo or straight 272's?

 

[Black_Bullet]

Im going straight 272s. If you feel there will be too much lose down low make up for it with other parts *( cyclone mani ) or something and better tuning to get some of your low end. At least thats my plan.

 

[Black_Bullet]

I spin my stock 130k mile tranny to 8.5k all the time. As long as I'm not using no-lift-to-shift, she shifts like butter, otherwise a little grind comes out of it. I don't think spinnign a stock trans past 7k is a bad thing, though.

No lift shifting actually is suppose to theoretically allow you to get into the next gear easier due to not letting off mommentum by taking your foot of the gas, then slamming back on it into the next gear. Keeps everything in sync better, or so Ive heard...
But of personal experience, i have a beat up 3rd gear syncro thats easy to make grind beyond 7000rpm, so coming out of 2nd into 3rd no lift to shift has made me shift into 3rd so much cleaner. If im doing any type of high rpm spirited driving i wont shift the car without doing a nlts.


And for the OP, this may interest you some.

AMSPerformance.com

 

[turboglenn]

Black bullet that webpage definately re-assured my confidence in desicion of cams

thanks!

 

[kahl23]

BTW, nice numbers Kahl23

Thanks! Actually was hoping for some slightly better #s than those (this was on 116) but for some reason the race gas tune on 'link that had run perfectly all summer ended up producing a lean condition and knock on the dyno. All I can speculate is that the gas, which had been sitting for a few months in a jerry can, had degraded.

 

[Black_Bullet]

Heres a review i just gave on the bc 272s posted in this thread...

http://www.dsmtuners.com/forums/cyl...er-272-combo-post151394216.html#post151394216