Dyno Test: Mod Progression

[LGAFF]

Results from Dyno Jet test.....VETTE December 1997
Test of 91 with stock tune and stock exhaust manifolds....

Stock 305hp@5600 304ftlbs@4400

KN 310@ 5650 303@4400

+Borla 327@5750 314@5000

+EH Porting 345@5850 339@5150
**Porting was extrude hone ...28hp/29ftlbs increase at 5100

[tomtom72]

Just curious, did they say if they port matched the I/H's to the head ports?

nice numbers with out a tune or headers. JMHO

[LGAFF]

They did not port match...

[VetteMed]

interesting info. Thanks for posting, Lee.

[LGAFF]

Stock Vs K& N


K&N(stock) vs Borla and K&N



Borla and K&N vs EH, Borla and K&N

[1990 quasar blue]

Wow only 305. I thought mine was a little weak when it only made 320/320 stock. Most seem to make 330 or so.

[gbmidyear66]

My car (also a 1 or 19 Quasar) Dyno'd last summer at 358 with Flowmaster and a custom tune....

[1990 quasar blue]

Originally Posted by gbmidyear66

My car (also a 1 or 19 Quasar) Dyno'd last summer at 358 with Flowmaster and a custom tune....

Not bad at all. That's three more hp than I got with ported plenum I/h, flowmaster catback and an HAT prom.

[Corbusa]

Do you guys have pictures to share of the ported areas? years ago I used to port match older heads , water pumps , intakes etc.. I would be interested in seeing some finish work- if possible.. For me when I get to the point of porting ,I'll send the heads to one of you Pro's on here. I won't gamble on a LT5 head..

[Paul Workman]

Some pix of work in progress, just to give you an idea...

The porting begins with a plan; it may be a copy of a successful model, or a new pioneering adventure. The point is, there is considerably more to it than making holes bigger. LT5 parts are expensive. So, unless you have experience with porting and have a basic appreciation for the principles at work, then sending it out to someone that does have a model will probably be cheaper and results predictable in the end.

I say this, because these pix of my setup may or may not be representative of what your's might look like, depending on the application - or it might be similar if you send it to IL for one of the FBI gang to do for you (recommended). I'm just saying...Mine may not look like yours or anyone elses. KThat said...

...this is a 90 IH. Notice the primary runner looks fairly clean. The injector buss is completely removed (the primary injector on the 90 is sealed at the top of the injector). What remains in the secondary runner is a nub of what was a rather large intrusion; the boss containing the seal for the secondary injector gasket.



In this picture you're looking down the IH at the head transition.



Here we see the head port matching in progress with the head in place. The ball gauge is a steel ball held by one of those magnetic wands. A plastic shower curtain is laid over the entire engine bay to keep chips etc from getting where they shouldn't be - like an operating room in a hospital!



I'll let you in on a little secret: Some only port match a short distance down into the head on the primary side. And, some don't even touch the secondary side of the head as it is already 36mm across. BIG (hp) mistake!

If you taper the port from the top of the head down nearly to the valve guide, then the shape of the runner will conform to good engineering practice as far as avoiding sudden changes in the passage diameter...if you get my drift. It WILL be worth the effort...as long as you don't stray off the line and get into the water or (worse) oil cavities.



A picture of the top of the head after the heads were fully ported.



Some feel removing the secondaries will not affect hp to any significant degree. Well, laminar flow dynamics says the highest velocity in the column will be in the center of the air column. How much hp is gained by removing them? I wish I could say. However, them being there flies in the face optimum flow dynamics principles. I removed mine. 400 RWHP is possible with plenum and IH porting, with proper head port matching, in conjuction with headers and a tune. Over 30 more RWHP is possible with full porting and cam timing.

Well, not a lot of detailed info. But, you get an idea of the symetry anyway.



P.