Hey all,
No real interest in a 350 at this time. I currently drive a 92 Z28 with a 305 tpi of course. As far as im concerned with a 1 piece rear main seal and roller equipped, its not a bad starting place for a strong street car.
Currently have a transgo shift kit, k & n drop ins flow master cat back and a 3.42 gear out back. I have clean used set of 059 vortecs and a b body lt1cam sitting in my garage. Im going to be installling headers and y-pipe and a 2000 - 2200 rpm stall torque converter. With my car being a speed density i was thinking that might be a good time for a tune. Lets call this stage 1.
At some point (funds permitting) ill install those 059's with the b body lt1 cam, the sdpc vortec tpi base and obviously a re-tune. Lets call this stage 2.
Anybody have any thoughts first on the combo of parts for a torquey street car application and secondly what kind of power would i be making after stage 1 and then stage 2 listed above.
Thanks

 

some folks here might have a better thought than me, but i'd say have some head work done if this is as far as youre going (motor wise). since the engine is a very inefficient air pump, i'd say maybe some intake work too. for more torque power, i'd recommend staying with the long tube runner design, but supposedly the holley stealth ram will make +65 hp (on a 350 tpi) out of the box. for a tune, talk to Tuned Performance on here, he does great work with the chips.

 

Thanks for the reply. Id love to go with a vortec hsr. For the money its a great deal, but from what i hear the hsr kills torque on a 305 in favour of higher rpm hp, which is but why i was thinking of sticking with the tpi set up with just a vortec tpi base to accomodate the 059 heads.

 

well the HSR is basically an LT1 manifold as far as i'm concerned, just made to work with these cars. the TPI can only go so high with the HP, and it seems to keep the same torque curve when you keep the LTR's. Could always spend the $600-800 on the Edelbrock intake combo, it leaves room for more porting so you can increase HP with keeping the same torque curve, only problem is that you'll be spending a lot of money between the LTR's and the porting. you can get the Edelbrock in vortec base, check the classifieds, there are sometimes ones going, they dont move as quick cuz they're vortec's.
but like i said, may want to check with a local machine shop on what they can do for how much money to increase power.

 

 

At what point does a sd car need to be tuned? I know cam and heads require tuning for sure, but does a full exhaust upgrade warrant a tune as well? It shouldnt change requirements for fuel and spark although toggling the binary's like turning egr off as im not going to be running headers with AIR tubes and raising max rpm etc couldnt hurt although not likely necessary. Any thoughts?

 

I would say if you delete the egr and air pump yes take them our of the tune. When the egr is commanded on timing advances during this lean condition.
The ecm expects to see air when the diverters opn and ads to the oxygen sensor reading,
A more free flowing exhaust or cai on a stock engine doesnt make much of a difference.

 

Not true at all, and think of what your saying. Installing an HSR allows for a larger volume of air to be drawn from closer to the combustion chambers, but it's still pulling that air through a stock throttle body. Meaning, the orifice of the throttle body bores haven't changed, so how much torque do you think your losing? Your simply running lean at that point, and the only reason you think your losing torque is because your introducing more air down low earlier that the ECM was never tuned for, and simply cannot correct fast enough for unless you tune your fueling. Also remember that horsepower is calculated torque, and if horsepower goes up, then torque must go up too, and if it doesn't, it is because you aren't tuned for it down low. Go with an HSR, and have Brian (Tuned Performance) burn you the right chip...

 

The L30s have the same effect on a 305 as the L31s do on a 350

 

I should have qualified my comment by writing that from what Ive read, the HSR reduces torque and and effictively HP in the lower RPM's in favour of higher RPM HP gains. HP is indeed calculated torque; however, engine speed is also part of that equation. So in theory low rpm torque and HP can decrease yet peak HP can still increase by virtue of the intake allowing the engine to continue to produce torque into higher engine speeds. Apparantly the long runner design of the tpi and the well documented issues with cylinder filling and lower VE of the small bore 305, makes them better suited as a low RP torque machine. Just trying to match my parts so they complement eachother which is why i selected a cam thats mild in both lift and duration.

 

What your reading is wrong, let's discuss it...

Wrong, any intake that effectively increases runner volume, and reduces the amount of time that it takes for the cylinders to pull incoming air into the combustion chambers (meaning shorter runners) allows for a more faster spinning, and a more higher revving engine. This does not reduce torque and horsepower in the lower RPM range, it simply allows for a more broader torque curve leading to a more broader horsepower curve. Again I want you to think, how can an HSR "effectively reduce" when your running the stock heads, the stock cam specs, and the stock throttle body?

It can't. Your only running lean at that point, which you need to compensate for with more fuel. When you alter your cam specs in favor for one that is designed for upper RPM, like the CC306 for instance, then what your saying is correct. Although even then your not losing any down low, your simply not maximizing down low, making the transition into mid and upper horrid. But getting back to the discussion, an HSR on a stock engine will only broaden your power curve, which is a good thing, you just need to tune for it...

With the stock cam? That is completely false, so put aside your theories. The specs of the stock cam have not changed, so no stall speed is needed, and there is no loss of power down low when it is tuned for. In that state you are merely running lean by introducing more air that that ECM is not tuned for, or that a carburetor is simply not jetted for, period. There is no such thing as a "torque motor", so get that idea out of your head, that is old school and ignorant thinking. A "torque motor" is a motor that produces and peaks higher torque values than horspower because the engine is being held back. Uncorking a stock engine allows it to breath, and peak horsepower increases, and torque remains the same but needs to be tuned for. You do not lose torque down low and increase horsepower up top as that is an oxymoron, all that situtation means is that your tuned up top, and not down low...

I am running a 23x/23x cam in my 305, and torque remains the same on the dyno both before, and after I siamesed the entire TPI system. I did not lose torque after opening it up, I gained torque, as well as gained horsepower due to the engine being able to rev higher. Like I said, go with the HSR and have Brian burn you a chip. The only way you'll lose torque down low is if you mismatch your camshaft on a stock engine that can't be tuned for, has nothing to do with putting an HSR on a stock engine that can be tuned for...

 

Thanks for the info. Sounds like Brian and Holley should put you on retainer. Haha just kidding buddy. Thanks again