I have a 87 5.7L Camaro. I had the engine rebuilt. bored 30 over,
put a crane compucam in it,put some 91 vette aluminum heads on it,bought some Accel 24lb injectors(which are a little less than a quarter of an inch shorter than the stock ones. is this a promblem?)for it,Crane aluminum roller rockers, a 58mm throttlebody for it,and ported the plenum.oh yeah, also some Eldebrock TES headers for it. now, the problem is,(if this is a problem.)The runners and intake are the stock ones that came on the car! the engine is still out of the car. should i wait until i can afford to buy a "big mouth" intake &larger runners, or will the stock ones be ok? the car has been sitting for a long time,and i'm really ready to put things back together and drive it! but i want all the punch that i can get out of it. your oppinions are welcomed.
thanks,Big John

 

I also bought a set of accell injectors and yes they are shorter but they will fit but make shure you put the little locks in the correct place so the injectors are held at the right level and not to high to be held in the manifold. make shure you lock them in the rail before shoving them in the manifold.

I have been running my 24LB accels for about a year and no leaks no probs yet.

Also it is very likely that it the performance gain for new runners, plenum, and TB should be statistically insignificant on your engine.

put it together and plant the right foot.

 

You'll be sacrificing maybe 15 hp and tq throughout the powerband, but the real disadvantage is when your powerband ends... it ENDS. The better TPI stuff will lengthen the powerband and when it runs out of breath it doesn't fall on it's face quite as bad.

 

hey, thanks for your input on my situation. so i'd lose about 15hp
without the new runners& intake. wow, that's a lot to lose,but this is going to be a daily driver not just for racing.maybe i can get the new stuff later this summer.
thanks again, Big John

 

I believe the intakes are good for only 4500rpms. Not good for racing anything except wheelbarrows. You need to change the runner/ intake system as it will choke out most of the mods you have. You will not be happy, although you will see some gain, so its deceiving. D Stroy H8 is correct.

 

I have to agree somewhat BigJohn. Yes the LTR style intake will always fallshort up in the high revs, but that doesn;t mean it can't pull SUPER HARD up to 5500 RPM. You need to hog out upper plenum, aftermarket runners, aftermarket base, EVERYTHING PORTED AND PORT MATCHED - should pull great.

 

hey,whats up Capt.Picard & D STROY H8
Thanks for your responses. no i'm not into racing wheelbarrows.
I guess you can tell that i'm new to this making power with TPI stuff. So, it really wouldn't make sense to use the stock runners & base with all the other goodies i've bought huh? okay. know anyone with a performance base and runners lying around?and will sell them for cheap? otherwise i'll have to wait until i can afford new ones. what brand do you suggest? ACCELL,SLP,TPIS,or EDEL.

 

SLPs are the cheapest runners, and have lots of meat for making the inside diameter ALOT larger than stock runners.

The bases are pretty much all the same. You have to port to get the potential out and any aftermarket base will have the meat necessary to port.

 

The SLP and Accel runners are basicaly the same.
SLP: 6.625 long 1.6 round 242.02 cfm
Accel: 6.625 long 1.615 round 245 cfm
stock: 7.25 long 1.47 round 203.17 cfm

bases are pretty close. You do not have to port them or siamese them to make decent power. The flow numbers verify this. A ported, port matched and siamesed aftermarket runners and base can flow in the neighborhood of 217-275 depending on how much you do. This is very good number wise. Stock is 203.17 cfm. HSR flows 275 straight out of the box. SR flow 220. MR flows 265 and 285.

Of course without the right set-up you wont see as good of gains.

The best way to figure out what you need (not the easiest) is the equation for CFM:

CFM= (CID x RPM x Volumetric efficency) / 3456

There are a lot more equations and ways to do things, You can use old dynos that match your set-up and try to use those for RPM and what VE might be. Math is better than just guessing.

 

Are you sure the injectors are shorter? Reason I ask... the only dimension that matters is the distance between the o-rings. I bet thats the same. Some of the injectors have a tip that people mistake as a critical dimension when its not.