BWilcox

Hi All,

Looking for a good high performance TPI street cam.

87 IROC, 5 speed.

Engine Details:

355 CI TPI
AFR 190 Heads, 2.02 /1.60, 58 CC, 10:1 CR
Modified Manifold Base-Plenum-TB, LPE Runners
Headers, CATS, Flowmaster

Presently running a crane 2032. A good Cam. Pulls to mid 5000 range.

Looking for more mid-range to high end power.

Not looking for a race idle sound but a nice street idle sound.

What about the CC502 or CC503.

Not sure how radical these cams are?

Can they be tuned reasonably?

What about emissions?

Kevin91Z

iTrader: (1)

Anything bigger than what you have will require a custom tune. Do you have that ability?

The two cams you mentioned are good. So are the Comp XFI268HR-113 and XFI280HR-113.

All of those will pass emissions easily with a custom chip. Where are you located?

Orr89RocZ

iTrader: (20)

agreed. either of those are nice grinds. i think the XFI280 is abit too large for non siamesed TPI setup but it would run and give a mean idle but not overall racey.

For more topend you'll need slightly moddified TPI setup to get more rpms out of it before power falls off.

CC503 cam tho is a great grind for all kinds of applications. I'd run that or the XFI268. Leaning toward the 503 grind tho over the 268

BWilcox

Thanks Guys.

The knowledge on this board is amazing.

Yes, I have some experience with tuning the 2032 cam.

Althought I would not consider myself to be even an average tuner.

My car is a MAF 165 ECU ($32B) setup.

The intake system is an interesting story.

I bought it from the owner of a racing engine shop in Ohio. My uncle works there.

Back in 88, the owner had a pretty healthy 377 /383 TPI setup.

As far as I understand, the TPI intake systems mods are as follows.

TPI baseplate : Extrude honed and ported.

TPI Runners : LPE Prototype Pieces.

TPI Plenum : Modified for better airflow.

Thottle Body : Also modified for better airflow.

Programming,,,,,

I was thinking about having Scott Hanson or TPIS burn me a starter EEPROM?

I could finish the job in Tunercat or TunerPro.

Big Cam Tuning,,,,,,,,,,,,

Increased Idle Speed?

Slightly Increased Idle Timing?

Increased Top End Fuel Delivery?

O2 Constants for Idle? Not played with these much.

Any other tuning thoughts?

Great news on the CAM selection.

I was very surprised to hear the CC502 and CC503 could pass emissions with tuning? Man they sound good on the video clips!!!

Do cars running these cams normally sound this healthy (good)?

TPI CAM selections seem tough to get my head around.

Talked to Fastchip and they have a very different opinion than the ones on this board. They indicated that the LPR lengh is too long to support intake duration in the 118 to 224 range (@ 0.050)?

Thanks again for the help.

These questions may be old news.

Best Regards,

Bruce

Orr89RocZ

iTrader: (20)

going up to around 220-224 intake duration is fine on a big tube setup. Sure that cam would peak up near 5500-5800 on a LT1 or Stealthram/Miniram car, but on a big tube TPI, it will help push power in the 4500-5000 rpm range and keep it from falling off as bad.

I dont know how tough your emissions testing is, but 503 can be made to pass. Cali smog? i'm not sure but they have gotten the 280xfi to pass there.

teh 218/224 XFI and the 503 would be a close match on your setup. You probly wont notice much of a power difference between the two

Oh and you can get a base tune thru email for 75 bucks from PCMforless. I got a base tune for my 383 there and i'll be noting how well it works in a few weeks

BWilcox

I live in NC.

Presently, my car is not emissions tested. Only a safety inspection is required.

Yes, I have attempted to contact Alvin at PCMforless.

Maybe i will play around with the CAM selection in DynoSim?

What type of induction system would be closest to my setup?

Long Runner Single Plane?

BWilcox

Hi Guys,

What is your opinion on the LPE 219/219?

I talkedto Alvin at PCMforLess and he suggested the CC502 or LPE 219/219 for my setup.

What are the idle differences between the CAMS?

In DynoSim, the LPE 219/219 seems better then the CC502.

Thanks for your opinon.

Bruce

Orr89RocZ

iTrader: (20)

thats a pretty good cam too. Revs alittle higher than the 502 cam tho. LPE does act like a slightly bigger cam than the duration specs show but its a good street cam. Very popular with superam setups and works well in long runner TPI setups too

Kevin91Z

iTrader: (1)

The LPE219 is at least 15 years old and old technology. If you like that one then pick the XFI268HR-113 instead. Its brand new and a much better camshaft, with better ramps and higher lift.

BWilcox

Hi Guys,

Thanks for the information.

The pistons I am using are TRW L2403F-030. These have a 15.2 cc dish and 4 valve reliefs.

At TDC, the pistons are down 0.004" in the bore.

The head gasket thickness is 0.039".

What what are the limits on Total lift and Duration before piston to valve clearance issues exist? When should I get concerned?

Also, I am using stock valve covers and would like to switch over to Roller Rockers (7/16" stud). What are my options?

Thanks Guys,

Bruce

Orr89RocZ

iTrader: (20)

with your setup you have a ways to go My cam is a 230/245 duration cam with abit over .600" lift and i got plenty of clearance on the intake and .120" on the exhaust. So once your in the 240's and near .600 lift i think you have to be concerned with PTV clearances. My setup is a 5cc flattop, zero decked and .041 inch gasket


As far as roller rockers, there are many available for 7/16 studs. I'm using Pro magnums from Comp cams. Steel rocker so they arent as light as a aluminum but they are strong as hell

IF you tuned that cam well... you should beable to handle the 268XFI cam..it should only require abit more fuel and few timing adjustments. It should idle about the same. MAF will compensate alittle

1989GTATransAm

iTrader: (3)

FWIW I had the ZZ9 in my car before I went to the XFI268 cam. The XFI cam idled every bit as well as the smaller ZZ9 cam and driveability is very good.

BWilcox

Hi Guys,

Sorry for the long delay.

Been running many DynoSim simulations.

Considering a custom cam based on the XFI 268 lobes.

Duration @ 0.006" = 268°/276°

Duration @ 0.050" = 218°/224°

Lift = 0.570" / 0.565" : I/E

LSA = 111°

IVO = 26° BTDC, ( LPE219 = 23° BTDC )

IVC = 62° ABDC, ( LPE219 = 67° ABDC )

EVO = 72° BBDC, ( LPE219 = 67° BBDC )

EVC = 24° ATDC, ( LPE219 = 23° ATDC )

To me, the IVC and EVO are very important.

The custom cam has an earlier IVC. Good for low-end torque and less reversion to the MAF sensor.

The custom cam has an earlier EVO. Good for upper mid-range and high end power.

The custom cam overlap is 50°. The LPE219 overlap is 46°.

Seems like this cam will sound fairly good and perform very well.

What is your opinion?

Easy or Hard to tune?

From the simulation viewpoint, the engine should run very well.

Thanks,

Bruce

Orr89RocZ

iTrader: (20)

i like that custom creation on a 111 lsa. will work good i think but will definately favor a heavily ported TPI lower and good runners. Siamesed would be best for more topend where that cam will want to go. Cam will want to peak near 5700-5800 and most TPI setups will flat out at 5200-5500 so the cam is a decent match but the more topend capability you can give it the better

even with tighter lsa, that cam shouldnt be too hard to tune with MAF sensor cars, really easy if you run open loop

BWilcox

Thanks for the comments.

I am presently running a "fresh" set of Comp 977 springs with Titainium retainers.

Installed Height = 1.9".

Seat Pressure = 135 lbs.

Open PRessure = 400 lbs.

Would these springs work with the 268 XFI lobes?

Thanks,

Bruce

BWilcox

Hi Guys,

Any comments on my last question?

The Comp -8 cores are made of austempered ductile iron.

I have read that the Comp specified spring pressures are too low for the XFI 268 cam.

However, I am concerned that the 977 springs have too much open pressure. Worried about long term cam lobe reliability.

Best Regards,

Bruce

Kevin91Z

iTrader: (1)

Why do you have your installed height so high?

And why did you go with 111 LSA? That will make the TPI setup harder to tune. I'd stick with 112 at the least, and 113 would be even easier to tune at the expense of top end, but you'd gain some mid-range torque (3000-4000).

If you already have these springs, 400 lbs is about the max I'd run with a hydraulic roller cam. If you want to change them, I have some Manley springs that are good.

Orr89RocZ

iTrader: (20)

yeah dont wanna go over 400 too much and definately want to keep seat pressure up over 130 for those lobes. I think that spring will work. I'd run LS7 lifters or equivalent. I wouldnt trust old stock lifters with pressure that high. Get some new ones. LS7's are cheap at 110 bucks a set but are good stuff.

BWilcox

Thanks Guys,

Given the Comp 977 springs, I had to set the installed height at 1.9 " to achieve ~ 135 lbs on the seat.

The 111° LSA sounds kind of tight. The seat overlap is around 50°. In my opinion, this is a "good" street overlap range. The Comp CC503 seat overlap is around 54°. To me, I think this custom cam is less radical.

Orr89RocZ thought the car would not be too hard to tune. MAF system.

Any other comments?

Regarding tuning,,,,

What kind of hints are applicable to the idle tuning?

O2 constants at idle ?

Proportional Gain at idle ?

Based on the overlap, I wonder if the WBO2 AFR will indicate the true AFR?

What is the best idle parameter tuning order?

Interesting information from Comp.

Given the -8 Cam cores ( SADI), the maximum open spring pressure should be below 425 lbs. Any comments from actual use?

Lifters,,,

I am using the Comp Pro-Magnum Hydraulic roller (OEM sytle) lifters. Comp indicated that I can run open spring pressures up to 425 lbs. Any actual use comments?

Thanks again and I look forward to your opinions.

Best Regards,

Bruce

BWilcox

Hi Guys,

Attached are the Dynosim results.

Closing the LSA from 113° to 111° helped to improve the overall torque and horsepower. Not great gains (wrt. XFI 268). Both XFI options appear better than the LPE219.

I have both the LPE219 and this Custom Cam. Either one can be installed.

Please help me understand the tuning difference between these options.

I have some experience tuning the Crane 2032. This is a milder cam.

Best Regards,

Bruce

Kevin91Z

iTrader: (1)

Dont touch the LPE219 cam anymore if you have access to the XFI268 or your custom cam. The LPE219 was a good cam 15+ years ago, but its outdated now.

The 111 LSA custom cam will have a choppy idle and you will probably be fighting a perceived lean condition at idle. What that means is the reversion from the choppy idle will flow across the MAF sensor in both directions, into the throttle body, and back out the throttle body. That will confuse the MAF sensor and make it seem like it getting more air than it is. The computer will respond by trying to richen the fuel, and your BLM's will be at 160 at idle. The car could also "surge" a little (plus or minus 150 rpms) at idle, as I have noticed when tuning MAF cars with big cams or tight LSA's (110).

Its all up to you, and how good you think your tuning skills are. The XFI268 with 113 LSA will be easier to tune, and you wont be giving up that much on the top end. You'll gain it in the low end and off-idle instead.

Orr89RocZ

iTrader: (20)

Its only a 50 degree overlap cam. I think there will be little reversion effects. That isnt all that much overlap for a 355. If i recall some of you cali guys are using cams like that, i think Allen is at 50 and his car runs good even tho it has more duration.

I think if you boost idle to 750-800 rpm and see how it idles on the crane 2032 tune, then make decisions on what to do next. I have a feeling that cam will idle fairly good on that 2032 tune with a 750-800 rpm idle speed. give it 22 or so degrees timing at idle and it should be ok.

My 383 is at 78 degrees overlap at idle and although the idle jumps around alittle occassionaly (+-100 rpms or so its pretty good where its at. I run open loop MAF tho so no o2' s to worry about. It did however run decent in closed loop when i played with o2 constants and such. My tune isnt perfect at idle, but its very driveable as is for a mid 11 second car and i dont feel like worrying about it anymore at this time. It gets the job done

I really dont think that 111 lsa with that duration will be too much a problem with MAF

Kevin91Z

iTrader: (1)

Allen and most of us in SoCal are using speed density.

You'll need to talk to Madmax and see how he's using MAF in his car. He's a diehard MAF guy while the rest of us have seen the light and converted.

BadSS

I ran a custom grind flat tappet hydraulic (similar to yours):
268/276
218/228
.308/.316
.493/.505 (1.6 rockers)
110 lobe seperation
108 intake center
112 exhaust center

9.8:1 compression 355, de-screened and ported MAF (helped to lean down the idle with the stock chip), stock chip, at first I only did timing and fuel pressure adjustments and it would idle around 700 rpm and jump up and down fairly regularly about 50 rpm. Once I broke down and finally burned my own custom chip it would idle fairly steady at 650 rpm.

So,, I'd say go with the 111 lobe spread cam you have.

355tpipickup

iTrader: (5)

whats the biggest cam that could pass emmissions "sniffer test" u think?

Kevin91Z

iTrader: (1)

It depends on if you can do your own custom chips or not. I'm running a 226/234 Lunati camshaft that passed CA's test in another engine. I'll test it in my engine next month, but I have no doubt it'll pass.

If you cant do your own chips, I havent gotten anything bigger than a ZZ4 to work with the stock chip.

BWilcox

Hi Kevin91Z,

Would it be possible for you to share your tuning ideas with the forum.

I am very interested in improving my own ability to use larger cams and still have reasonable emmissions.

Best Regards,

Bruce

Kevin91Z

iTrader: (1)

I'm not a written-word teacher, I'm better with hands-on teaching. Try reading the "introduction to PROM burning" tech article. That'll give you a good place to start.

Putting a bigger cam in a TPI engine usually makes it rich at idle, so you'll want to lower the fuel tables. That'd be the lower VE table in a SD car, and the MAF scaler tables in a MAF car.