91_z28_guy

InfernalVortex

iTrader: (4)

Probably around 250hp. Just a guess... seems like not much has changed on teh top end except for the cam. Depends on how much bigger that cam is than the stock L98 cam, but it's a pretty mild cam. Which is good for TPI...

91_z28_guy

WELL WHEN I ORDERED THE CAM I TOLD THEM THAT I WANTED THE BIGGEST CAM THAT I COULD INSTALL WITHOUT HAVING TO CHANGE ANY COMPUTER STUFF. SO N E BIGGER COULD HAVE CREATED SOME SMALL PROBLEMS.

sofakingdom

iTrader: (1)

Looks to me like pretty much a stock rebuild, except the pistons are probably .020" lower in the block than they were like almost all SpeedPro or other "rebuilder" pistons, which lowers the compression a few tenths of a point.

TPI imposes fairly strict requirements on the cam design. It uses the pulse of pressure in the intake created by the closing of one intake valve and the air rushing down the runner suddenly slamming into the closed valve, to reinforce later cyl fill events. The cam has to be compatible with this "tuning" (the "T" in "TPI" stands for "tuned") in order for it to work; it's VERY easy to put in an otherwise perfectly "good" cam, but it react negatively instead of positively to TPI's specific behavior.

So whatever it had stock, that's what it's got now, minus the loss from the reduced CR, and the loss from whatever mismatch the cam creates, if any. Without knowing that, it's impossible to guess how much lower than stock you're getting from it.

Lose the all-caps. It's extremely rude, because it's very hard to read, and it makes it look like YOU'RE SCREAMING AT US. We don't like that out here. Trust me, we'll hear you just fine if you use proper writing technique.

91_z28_guy

Sorry about the caps.... well i had installed the cam before i rebuilt my motor and everything was fine. So hopefully with the fresh rebuild it will all work out, i just didnt know what i was looking at with the horsepower range which probably isnt going to move much over stock huh??

sofakingdom

iTrader: (1)

Yup; probably not much over, and more likely, slightly under.

91_z28_guy

Why slightly under??

sofakingdom

iTrader: (1)

Because, as you no doubt already have read:and

Air_Adam

If you can find out specifically what cam you have (part number is best) then we could much more accurately tell you if its helping/hurting performance. Lift numbers don't mean much - its the duration thats important.

Saculia

iTrader: (1)

I don't know how it is for the 350 rebuild pistons, but for the 305 the speed pro rebuild pistons do come with the correct compression distance of 0.0560 inches. The ones from federal mogul come with the 0.020 lower compression distance. So I think that speed pro should be OK, but if you have the part number you can verify that.

As far as the cam is concerned, comp cams makes a good cam for the 350 and 305 TPI engines. It is the 08-501-8. I am currently running the 8-500-8 in my freshly rebuilt 305 TPI. I was guaranteed by comp cam that this cam would work with the TPI intake and not send the speed density computer into a frenzy. both of these cams have a shorter duration than what he has chosen.

sofakingdom

iTrader: (1)

SpeedPro = Federal-Mogul

Go visit www.federalmogul.com and take a look at their brand names across the bottom of the page.

Virtually ALL SpeedPro/TRW pistons are an extra .020" lower than stock; they give the "nominal" 1.56" (not 0.0560") compression height spec in their cataolg, but if you measure 350 or 305 ones, you'll discover they're almost all 1.54". The only ones that aren't, are a few of the high-domed ones. BTDT.

But all of that is really just monkey-spank and running off at the mouth and drivel. If it really matters to you how much power it's putting out, go hit the chassis dyno. Stock, those cars did around 195 HP to the wheels; easy to get them to 215 or so without major parts changes. The biggest improvement you can make to a stock one is headers, which will take it right directly to 215ish. The rest of that stuff you see people talk about like porting the plenum and airfoils, makes less of an increase than the normal produtcion tolerance variation from one car to another. So take it to the dyno; if your RWHP is much above 200 with manifolds or 220 with headers, then you improved it; if it's much below 210 with headers or 190 with manifolds, then it's weaker than it was.

Talking about it won't get you any closer to knowing what it is, or to improving it.

91_z28_guy

WELL IF IM WRONG JUST TELL MY BUT IN THE FORUM FOR "MY" CAR. 1991 Z28 IT'S SUPOSED TO HAVE 245RWP FROM THE FACTORY NOT 190. SO DO YOU HAVE THE CORRECT NUMBERS, OR IS THIS TAKING THE CAM INTO CONSIDERATION(IF ITS DECREASING POWER)

ALSO CAM NUMBERS: 262/264 DURATION

sofakingdom

iTrader: (1)

Please lose the EXTREMELY RUDE ALL-CAPS. We can hear you just fine without you SHOUTING at us. It is very difficult to read that.

Yes I have the correct numbers. I've stood beside enough dynos watching enough of those cars run, to have a pretty good idea of what they do.

TPI 350 motors have 240ish at the flywheel from the factory depending on year and car (Camaros have a few more than Birds because of the terrible Bird air intake, for example), which ends up being about 190-195 at the wheels.

To really guess at whether the cam is really right for TPI or not, we'd need the cam part #; or the FULL specs ("advertised" duration, .050" duration, & lift on both lobes, lobe separation, ICL).

91_z28_guy

Sorry about the all caps i work with them on all day and somtimes forget to turn them off somtimes.

DJP87Z28

No 350TPI came from the factory stock with 245 RWHP they were rated at the flywheel and NOT the rear wheels. And my guess you are making about 225 hp.

91_z28_guy

Well D*#$ that just flat out sucks.......

sofakingdom

iTrader: (1)

How do you know?

Go get it dyno'ed, and see.

Maybe you'll get a pleasant surprise. Maybe not. Only one way to find out. Sitting here talking about it, isn't going to reveal the ultimate truth.

Although I will tell you, a trip to the dyno can be a TRULY humbling experience. Usually is, more often than the other way. But, reality is reality; mouth racing is .... runing off at the mouth; which one REALLY matters?

Air_Adam

It depends - what cam do you have? Those duration numbers were 'advertised' duration (I hope) which really doesn't mean anything (don't make me explain why, it takes too long lol).

Do you have a part number for that cam?

91_z28_guy

08-300-8

sofakingdom

iTrader: (1)

OK: that's a decent cam for TPI, although a bit in the small side... it's 206°/210° @ .050", .450"/.480" lift, on a 112° LSA.

Here's your stock cam... https://www.thirdgen.org/mods3 down at the very bottom of the page.

The "300" grind is basically a slightly better than stock replacement for a L98, although it would be an upgrade for a TBI motor (those came with that pathetic 155 cam in the list there).

No massive difference in power from it, compared to stock, I wouldn't say. Maybe a hair more, but mostly, pretty comparable.

Time for a trip to the dyno.

DJP87Z28

[QUOTE=91_z28_guy;3683542]08-300-8[/QUOTE


Don't go into shock when you dyno your car and your RWHP numbers are in the 190/200 range. You just don't have the mods for major increases over stock.

Go to www.dynojet.com and plug in your Zip code the Dynojet location near you. Average cost is $75 for three pulls.
Good Luck

Air_Adam

Thats a decent cam for a mostly stock rebuild, you should see a bit of a gain with a cam like that. Not a huge gain, but some. Its pretty similar to the LT1 camshaft actually, just a smaller LSA (that cam is 112*, stock is 114*, LT1 is 117*). The smaller LSA may give it a slight bit more 'bump' at idle too, but maybe not - hard to say.

InfernalVortex

iTrader: (4)

I thought they stopped rating at the flywheel and started using numbers closer to real world rwhp?

Interesting to know, either way. So my L03 put down a staggering 130 or so hp to the rear wheels?

sofakingdom

iTrader: (1)

Right: the factory's "ratings" are at the flywheel, but with a representative production-line motor as installed in the particular chassis, with the stock exhaust, stock air intake system, stock accessories all installed and operating (not things like power seats or A/C, but rather, the AIR, EGR, water pump, alternator, etc., whatever HAD TO BE on the car in question for it to be old), no special tuning or programming. As opposed to the 60s method where a bunch of marketing guys sat around in a smoke-filled room and made up something that sounded good that the liability insurance carrier was willing to go along with; or like eBay ads, on an engine stand, with a dyno carb, dyno headers, no alt, no water pump, no PS, no emissions, no air cleaner, no mufflers, hand selected off the production line for stringent quality control, tweeeeked to the 9s, etc.

Power at the wheels is usually 20-25% less than power at the flywheel. Manuals lose less than automatics, and since there are certain losses that are independent of power and others that are proportional to it, the "percentage" of loss tends to be lower the higher the HP is.

But yeah, a 170 HP L03 typically does 130ish to mid 130s at the wheels, in absolutely stock trim. Maybe 140 for a 5-speed.