Alternative Port EFI IntakesThis board is for tech discussions and questions about aftermarket port EFI such as the HSR, MR, SR, BBK, FIRST, etc.
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I put the engine together ten years ago in my 87 IROC and have always been a little disapointed in the performance of it. The engine consists of - zz4 short block, old school trick flow heads (crap valve springs still on them), CC .498 I, 509E, 218 / 220, SLP T-Ram intake, Crower 1.5 - 1 SS roller rockers, 1 3/4" SLP headers and cat back, Random Tech cat, rebuilt 700R4 with 2800 stall convertor, 56 mm Arizona Speed and Marine TB, stock LS1 injectors and stock 3.42 geared 10 bolt. There are alot of other supporting parts but these are the basics.
I bought a set of AFR 195cc Eliminators this summer along with a set of custom made Cometic head gaskets that should raise the CR to about 9.8 to 1.
I would like to install another cam and was thinking about something in the .560 lift range, 230+/- duration, and 113 LSA. The MAF is a stocker and I dont plan to make the swich to SD.
Would love to get some input from you guys regarding camshafts. Any input will be appreciated.
The goal would be to run in the bottom 12's and still have decent street manners. It isnt a dailey driver (9K miles in ten years) but dont want bad manners in traffic.
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I ran 12.36s around 109mph with a similar set up and a StealthRam intake, 9.8:1 355, old style G1 TFS heads (good valve springs to match the cam), 218/228 - 110, .493/.507, 1 5/8" shorty headman, 3" Dynomax, 3.23 gears, 3000 stall. If you were off that mark by .15 or more (with slicks),, I'd really try and figure out what was "wrong" before moving on,, maybe you have already - the springs that came on those older TFS heads were junk!
Anyway, with the AFR 195s, 350, and your intake and exhaust,,, you're going to want as much lift as you're comfortable in running, but keep the duration in the 224/230 range on a 112 spread. That'll match the intake's power band better and let the MAF system "work" a little better (than a larger cam).
I have only had the car at the track a couple of times, best ET was 13.01 @ 104.? I know the ET could have been wittled down to high 12's with more runs and sticky tires but the MPH seemed off by about 5. It should have run close to what yours did.
I know the valve springs are shot, they are the stock TF's with a hard 9K on them. The engine only had 30 miles on it when the transmission went. On the way home from having the transmission rebuilt I matted it at 50MPH. The tranny downshifted into 1st gear, 7500 RPM. This happened a couple of times. I am sure that finished off the springs.
AFR claims that there springs are good for .600 lift and I am not opposed to getting close to it.
Do you think a 112 LSA and 230 duration cam will still be tunable and have decent street manners? The other thing to consider is that the short block is a stock ZZ4. The rod bolts will be the limiting factor for 6200+ RPMs?
Had to pull out the cam card for what it is in now, sucks to get old! Crane Cam HR 276-2S-12 IG, .488I, .509E, 214 and 222. GMHT magazine featured a GTA that had the same setup as mine back except for ported heads in the late 90's and the guy claimed he ran 12.20s @ 110 MPH with it.
Do you think a 112 LSA and 230 duration cam will still be tunable and have decent street manners? The other thing to consider is that the short block is a stock ZZ4. The rod bolts will be the limiting factor for 6200+ RPMs?
It'll be tunable, but with the AFR heads and lifts in the .570 range it's not going to take much cam to hit 6400 rpm. I mean I was shifting the 350 StealthRam with the 218/228 -110 cam and heads not remotely close to the power and RPM potential of the AFR195s at 6400rpm. Just a swap to AFR heads and it would probably wanted to shift in the 6700 range. Based on the intake shoot-out dynos,,, it looks like the T-Ram would probably shift about 400 rpm less than the StealthRam. So,, I'd keep duration on the intake 218 - 224 and the exhaust 224 - 230 if you want to keep the shift point in the 6300 range with the T-Ram.
Yep,, I can believe 12.20s with a decent port job on the old TFS. Where did your TFS with the 214/222 - 112 shift? Around 5900? It should have if the springs would have let it.
I probly keep duration in the mid 220's and lift near .560-.570's. I'd recommend upgrade to AFR's better 8019 springs but the 8017's will be ok if you stay under 6200 rpm.
230 cam will want to spin over 6500. 220's will give you want you need. I shifted near 6800 with my 230/245 cam but it was on 109lsa and in a 383. No problems tuning with MAF.
It'll be tunable, but with the AFR heads and lifts in the .570 range it's not going to take much cam to hit 6400 rpm. I mean I was shifting the 350 StealthRam with the 218/228 -110 cam and heads not remotely close to the power and RPM potential of the AFR195s at 6400rpm. Just a swap to AFR heads and it would probably wanted to shift in the 6700 range. Based on the intake shoot-out dynos,,, it looks like the T-Ram would probably shift about 400 rpm less than the StealthRam. So,, I'd keep duration on the intake 218 - 224 and the exhaust 224 - 230 if you want to keep the shift point in the 6300 range with the T-Ram.
Yep,, I can believe 12.20s with a decent port job on the old TFS. Where did your TFS with the 214/222 - 112 shift? Around 5900? It should have if the springs would have let it.
I only made a couple of passe at the track with this settup. IMO in highndsite, the valve springs were shot. The first pass was the best, left in drive, shifted at 5600 RPM. Before the transmition blew up it put down 298 rwhp, but was running extremly lean and made the same HP at 5800 as it did at 6400. Then the next day the tranny grenaded. A couple of weeks later the tranny was rebuilt and the shift point problems occured. This wiped out the valve springs. Then I went to the track.
I would like to correct the tuning and hardware parts before stepping up, but I think it now is a mute point. I will install the FAR 195's and a larger cam and have a custom tune.
I trust your opinions and appreciate your input.
With what I have desribed as parameters, what would yo suggest for a cam?
With what I have desribed as parameters, what would yo suggest for a cam?
With your 1.5 rockers, I’d get comp to cut me on a 112 spread, 108 intake centerline:
Intake – Lobe 3192 – 276/224/152 - .567 (1.5s)
Exhaust – Lobe 3194 – 282/230/157 - .584 (1.5s)
Anything smaller on the intake duration and you're going to start flatlining the top end,, just like you saw with the 214/222 cam.
If the T-Ram flows like a superram, that combo should put down 340-350whp I would think. Thats a healthy cam and good heads. Thats good for low 12's all day
Orr, my current set up put down 300 RWHP, I hope that I get more than 30 - 50 RWHP with a .5 bump in CR, bigger cam, good valve springs, and better flowing heads and tune that works. The 300RWHP was with an A/F ratio over 15 to 1.
I rhave run my brothers 6 litre GTO in cool weather, on the low end we were dead even and pulled on the top end, with the wasted valve springs. In 40 degree warmer weather, he pulled 4 cars with my car pinging like a MF.
I hope so, my brother has a .610 lift cam, LS3 heads and Kooks headers on the bench for his GTO. He doesnt think my IROC will be competition for his goat with both of our winter mods. Can you sense the brotherly love? My wallet does.
14psi, street tune 
