NA build started

[mrvax]

thanks man! Its good to see that you are keeping the car. I read your thread on the upgrades, and I hope it handles well.

The reason why Im worried about going with cams is that I have had bad experiences with them, with the 10.3-10.5:1 compression and spinning the motor over 6k. A lot has changed since the archaic days of regrinds though

I'd be terrified of regrinds. If I was getting cams, I'd only get the ones that people here have successuflly installed with your C/R. Then you can be confident it will be OK.

 

[Winters98GT]

well, after emailing with Bill Putnam today, he advised against me getting a stage 1 cams like the VT. On his car, they made peek hp at 6100rpm, which would require me to shift the car higher than I feel comfortable doing. He said that the ported heads will definetly help out even with stock cams. I guess that if I go with cams, I will be looking at NPI grinds that make peek power under 6000rpm. I think that will benefit the car more since I plan on shifting around 6100-6200rpm. What do you all think?

 

[CobraRed_96_GT]

sound fine to me, im still going to have my shift point at 6/6.1k regardless of where my peak is w/ VT cams. Most modern cars peak power at redline anyways, as more air is comming in and fuel is being sent faster - so this makes sense to me

 

[Winters98GT]

sound fine to me, im still going to have my shift point at 6/6.1k regardless of where my peak is w/ VT cams. Most modern cars peak power at redline anyways, as more air is comming in and fuel is being sent faster - so this makes sense to me

Chris, do you know of anybody that has gone with non pi cams on pi heads?

 

[CobraRed_96_GT]

Chris, do you know of anybody that has gone with non pi cams on pi heads?

none, i see people using 268's on NPI heads - but never a NPI cam on a PI head. You talking reground NPI cams, or just NPI cams?

 

[Winters98GT]

not reground, new cams.

 

[CobraRed_96_GT]

not reground, new cams.

so new cams made for NPI heads? Like the xe268's?

 

[Winters98GT]

so new cams made for NPI heads? Like the xe268's?

thats what Im leaning towards, still unsure about it though

 

[CobraRed_96_GT]

thats what Im leaning towards, still unsure about it though

dont 268's have more duration that ex262's for PI heads just less LSA? High duration makes the powerband move upwards correct?

Bill Putnam:

Personally I believe that if you have good valve springs that you can rev a 2v to 6500-6700 RPM al day long with no issues. Many of the people with failures ran comp cams and that just seems like too much of a coincidence to me. Last night I launched my car 3 times on the 6700 RPM limiter, plus missed a gear and saw the tach rev to 7K twice. I'm pretty close to just moving my limiter to 7K.

 

[TGJ]

The Comp 268's have more duration, less lift and the same LSA when compared to the PI 262...

I do think the 268's will work for you, but I think you would be better off with the PI 262 grind. There was a test of all of comp's cams on the same car. The PI 262 version made more power and had a broader power curve than the 268's. I have an MS Excel file of this comparison.

 

[TGJ]

Here is the data of the PI 262 VS NPI 268: In bold is the max HP and TQ.

RPM 268H-HP 262AH-HP 268H-TQ 262AH-TQ
2500 136 139 285 293
2700 145 149 283 291
2900 160 162 289 294
3100 178 184 301 311
3300 206 210 329 334
3500 220 229 332 343
3700 236 244 334 346
3900 261 266 350 358
4100 278 283 354 362
4300 292 299 354 366
4500 308 321 360 374
4700 331 342 370 382
4900 349 356 374 382
5100 360 364 371 375
5300 366 369 363 366
5500 372 376 355 359
5700 379 383 349 353
5900 381 385 339 343
6100 377 378 325 325
6300 373 370 311 308
6500 364 361 294 292

 

[CobraRed_96_GT]

that looks like it's on a blown application tho - which would always favor more lift

 

[Winters98GT]

Chris, thanks for the info man. This is what he told me today.

Bill Putnam-

I think you could get down to that ET range without cams but it would take a lot of practice to get the most out of the car. You should see gains from the ported heads without cams but obviously aftermarket cams will help out. As to what cams that I really can't say. My only first hand experience was with the VT stage 1's. There are so many new cams out there to choose from and honestly what you would need to do is look at dyno results from them to see how the cams changed the power band. You want something that is going to peak below 6K and from what I've seen most cams peak just over 6k. My stage 1's I believe peaked around 6100 and unless I shifted at 6500-6600 RPM I didn't gain anything at the track.

I think everyone is recommending the cams because if you are doing the headswap now is the time to do the cams while it's all apart. However I also see where you wouldn't want to spin it too high on a high mileage engine that you personally haven't maintained since day 1.

Bill

 

[Winters98GT]

Here is the data of the PI 262 VS NPI 268: In bold is the max HP and TQ.

RPM 268H-HP 262AH-HP 268H-TQ 262AH-TQ
2500 136 139 285 293
2700 145 149 283 291
2900 160 162 289 294
3100 178 184 301 311
3300 206 210 329 334
3500 220 229 332 343
3700 236 244 334 346
3900 261 266 350 358
4100 278 283 354 362
4300 292 299 354 366
4500 308 321 360 374
4700 331 342 370 382
4900 349 356 374 382
5100 360 364 371 375
5300 366 369 363 366
5500 372 376 355 359
5700 379 383 349 353
5900 381 385 339 343
6100 377 378 325 325
6300 373 370 311 308
6500 364 361 294 292

TGJ, thanks for the info on the two cams. However, as CobraRed said, this does look like a blown motor.

 

[CobraRed_96_GT]

Chris, thanks for the info man. This is what he told me today.

Bill Putnam-

yeah, i agree with 6100 although having 10.4:1 or so changes where your main power hits slightly. My guess is that with a stall TC cams really compliment this, and i should put my 1-2 shift around 6k and my 2-3 shift around 6.1K and that's all the shifting i need to do in the 1/4 or 1/8th so im hoping for gains over stock PI cams in the 5200 range too.

 

[Winters98GT]

guys check this out. Look at the numbers with the 268's on stock PI's

http://forums.modulardepot.com/4-6l-2v-tech/48206-96-gt-dyno-after-head-swap-cams.html

these cams are proboly what I want to go with.