ok i was reading around about perfomance parts, and i cam accross edelbrocks heads and cam for the LT1

and edlebrock said "On the dyno, the head/cam matched duo out-performed the stock Corvette LT1 by 73.1 hp and 36 ft./lbs. torque, as well as raising the peak power level by 500 rpm!"

which proposed a question do me, What determins the red line, like mine is stock now at 5700 or so. Are they claiming my hp curve will go another 500 rpms? or are they claiming that i can rev 500 more rpms going to 6200? and if thats true what has to be done for my tranny to shift at that instead of 5700?

i know some of u guys can rev to like 6600 rpms or even more.

with these claiming to raise peak power by 500 rpm, i donno if that is even good isnt it better to have the power in lower rpms?

 

I dunno about that..I read about those on paceparts.com and those heads only make 24 more hp then regular LT1 heads acording the edlebrock, thats crappy for a set of heads...thats the reason there so cheap

 

I would say you would be much better off porting your heads or buy some LT4 heads. For the price don't think it's worth it.

 

im not really interested in the heads or cam just the info in my first post

"What determins the red line, like mine is stock now at 5700 or so. Are they claiming my hp curve will go another 500 rpms? or are they claiming that i can rev 500 more rpms going to 6200? and if thats true what has to be done for my tranny to shift at that instead of 5700?

i know some of u guys can rev to like 6600 rpms or even more.

with these claiming to raise peak power by 500 rpm, i donno if that is even good isnt it better to have the power in lower rpms? "

 

Ok, he said "head and cam" package from Edlebrock.

The rpm redline gets moved up due to the flow characteristics of the heads and the profile of the cam.

 

what kinda flow do u need to get an lt1 up to 7600 rpms?

or someplace high up like that?

and if u were to do that would it still be streetable?

and how do u determin the redline, like ive read many topics on here after people get down w/ there cam they go dyno it, and stop with the accelorator after a certain rpms (like 6600 or something) due to uncertainty, but yet there horsepower curve isnt finnished pulling.

when u do such a procedure how do u alter your tranny to allow for the higher shifting.? (a4 of course)

 

"On the dyno..." leave alot to be open imo.

Marketing=stretching the true. They have thier own engine dyno which I am sure is the type of dyno they were using. They make no mention that they did or did not use other aftermarket components to compare thier combo to a stock LT1 dynoed I am sure with all the accessories and the stock exhaust. I would bet you that they did the dyno with open LT headers on an engine dyno. Its too much trouble fixing up a stock exhaust in house on an engine dyno. Most just slap LTs on. They are not telling the whole true unless they say "with no other modifications"
A good example is th LT4 hotcam kit advertised at 425hp

Jeff D.

 

but what about the people on here?

ive seem many topics where people get nervous and kill the throttle at high rpms... it seems they donno the max of the cam and head combo... so how would u determine it? via mathmatically or what not?

 

You can set the redline to anything you want it to be via programming. If the cam makes peak hp at 6200rpm then why rev past that? Longer duration cams power peak comes on later in the rpm range. Most cam manufactures have the rpm ranges posted on thier wbsites that thier perticular duartion cams make peak power. You need a dyno graph to see where the rpm peak really is for your personal setup.

Jeff D.

 

whats the value of having the gearing going past the hp peak?

wouldnt it be more useful to setup the gears to bounce from hp peak down to torque peak and pull back up to hp peak and then back again?

 

Ok, HP is HP is HP. It doesn't matter what RPM it is happening at. HP is a function of tq and rpm, the three are mathmatically related. So the fact that the HP peak is 500 rpm higher doesn't really mean anything except that you will need lower gears to make use of it. It's not better up at a higher rpm.

Your right, it's better to make the same power at lower RPM. Now more tq at a higher rpm is good, because more tq anywhere implies more HP. But HP already includes rpm in it so 500hp@5k rpms is just as good as 500hp@6k rpms. There is a limit to the amount of tq you can make from a certain displacement. Therefore, the typical way to make more HP is to maintain the torque at higher rpms, which causes the hp peak to be higher in the rpms. In this case they claim they increased tq by 36 ft lbs. But they were able to achieve a larger HP increase by maintaining the tq at higher rpms.

Typically a decent motor will have the HP peak equal to the tq peak. A higher rpm motor will have the HP value much larger then the tq value. This is because they are maintaining the tq at a higher rpm and can therefore use lower gearing.

With lower rpm hp there is a lot less stress on your bottom end and on your vavletrain. There will be less wear on your other accesories and transmission too.

Redline is wherever the person decides it is. Most often the redline is determined by the valvetrain although it can also be limited by the bottom end. It's whatever the person who is driving is comfortable with. The GM engineers decided the stock valvetrain was limited at ~5800. I have a cam and upgraded valvesprings which gave me the confidence to raise the 'redline'. I feel the redline of the stock bottom end is 6500. That is just my opinion. Therefore i selected a cam that would peak around 5800 and allow me to shift around 6200, giving me a comfortable buffer zone before the stock bottom end redline. My vavletrain revline is also probably around 65-6600 rpms. That is where the ramp rate of the cam lobes i selected would become to aggressive and cause vavle float (the lifter to come off of the cam at the inflection point) and possibly valve bounce (the vavle bouncing on the seat). If i were to upgrade to lighter valves, lifters, a cam with lower ramp rates, better springs, then the vavletrain may safely support 7500 rpms. I'd still be limited by what i'm comfortable with on the stock bottom end. Some guys rev the stock bottom end to 6800 regularly and have not had problems. Others have revved to 6300 1 time and spun bearings. It depends if you have money for a rebuild how far your comfortable pushing it.

When GM made the LT4 with the higher ~6200 rpm redline, and LS6 which also peaks and redlines at higher rpm then the LS1, in both cases they used lighter valves and better valvesprings. That is consistend with how people raise their redline.

Your shift point should be when your tq@ the rear wheels in first gear is equal to your tq@ the rear wheels in 2nd gear and so on. This is typically ~400 rpms after the HP peak, but varies by the combination. Another way to estimate your shiftpoint is to select it so that the HP before the shift equals the HP after the shift, this maximizes the area under the hp curve. This will give very similiar results to calculating the actual rwtq in the different gears and finding where they intersect.

Your transmission needs to be reprogramed via the PCM. Any major mods that will significantly raise your redline and HP peak will require your PCM to be reprogrammed anyways.

I talk a lot.
-brent

 

torque has rpm's measured into it too doesnt it?

300 torque@ B rpms is the same as 300 torque at A rpms

and how do u know if a cam or a head is gonna be a steet or strip?

 

You need to start doing searches on this stuff. You had fairly specific questions so i tried to answer them. There are more gracefull explanations out there though.