Winter Porting Project Done!

[gbmidyear66]

I was having problems last summer with my idle and intermittent SES light - which I ultimately figured was a problem with the throttle body binding - so decided that since I'd have it all apart over the winter to repair the TB - might as well port the top end at the same time (and take out the starter and clean the valley)

I sent the TB off to Marc Haibeck to repair and Port. I arranged for Lee Gaffigan to exchange my Airhorn, Plenum, Intakes and Coolant Tubes - which he ported and Powder coated for me. I got new gaskets and bolts from Jerry.

Finally got her all back together this weekend. I could never get the car to idle below about 750 without turning on the A/C, and I had IAC of zero when the car was warm. The Engine now idles smooth as silk at 675 RPM and with the engine at operating temp I have an IAC of 23 (Marc promised I'd get 20)

Marc, Lee and Jerry are all very helpful and great to deal with - wanted to thank them for their help / service - couldn't have done it without them.

I'll post before and after dyno results once I have the new results.

Here's a few photo's....

[RHanselman]

Congrats, looks very nice...

Cheers,
RH

[RICKYRJ1]

one can never tire from looking at a refinished LT5! Hard to find a better lookin GM engine out there. Nice Job! Enjoy!:saluting:

[ZZZZZR1]

Plenum looks great!

Wow my idle has never been that low.... Very nice!

:cheers:

David

[LGAFF]

Thanks Glenn!!

[A26B]

You done it all right! looks GREAT & obviously is doin' the nickel dance.

[gbmidyear66]

Thanks Jerry, Yeah - the idle is a big improvement, night and day

Just ordered the parts from you I need for one of next winters projects (powder coat cam covers to match)

[HAWAIIZR-1]

Its always nice to hear these success stories and I never tire of them. Thanks for sharing the great news.:cheers:

[tomtom72]

YES! Just like Rick and Craig said.... our motors are the best of the breed in both performance and looks! Yours sure came out sweet!

So glad that your project exceeded your expectations! :thumbsup:

:cheers:
Tom

[LGAFF]

Bump for color check

[Paul Workman]

Congratz on your successful mods and renovation! But the best is yet to come! At those mods you should be putting down 50-60 more ponies!

P.

[Blownrunner]

I did the same to mine this past winter: plenum, injector housings, water pipes, throttle body, and air horn in light silver with black lettering. Had a few issues with the throttle body but along with the injector change it runs great! I also changed O2 sensors a month later and it really runs sweet now!

[gbmidyear66]

Lee - were you looking for the color code for the powdercoat I chose? It was...

SK544MIRROR SILVER SPARKLE (SINGLE STAGE) (Powder by the Pound)

OK, that was last year's project..... I have shamefully ignored the beast most of this winter (I have kids that consume most of my spare time) - but have gotten busy the past few weeeks.

- Re-did rear brake system (new braided SS lines, slotted zinc coated rotors, Hawk pads)
- Noticed the clutch resevoir near empty - finally installed the new slave cylinder that's been sitting on my workbench for a year
- Now I am fighting a "simple job" of changing the oil. Taking the easy way out allways catches up with me..... I went to "Mr Lube" last year and had them change my oil. Well the drain plug is now damaged and WAY overtight. No luck with a bolt extractor, no luck with vice grips. I'm now letting it sit with penetrating oil on it. If that doesn't help - what I am left with? - drilling it out?

[gbmidyear66]

Paul - you are close....

I went from 354 RWHP (baseline with flowmaster exhaust) to 392 RWHP +38 RWHP from Lees top end port.

From what I observe - it does not seem that I have left much on the table for the RWHP I am getting for the mods I have done?

I am guessing the next cheapest/easiest thing to do is headers....

[Fully Vetted]

Those are good numbers. Corey just finished mine today and it did 430 whp WITH headers. Looks like you're already there.

[Paul Workman]

Paul - you are close....

I went from 354 RWHP (baseline with flowmaster exhaust) to 392 RWHP +38 RWHP from Lees top end port.

From what I observe - it does not seem that I have left much on the table for the RWHP I am getting for the mods I have done?

I am guessing the next cheapest/easiest thing to do is headers....

Wow! If you're getting those numbers with/out headers...then you really do have a runner there! E.g., if you were at 354 baseline, you were 15-20 above the average for a stock 375 motor to begin with. What year is your Z?

Quite a bit o science involved to optimize (any) motor's performance, e.g., runner length and diameter, various angles, tapers, etc. And, in lieu of that - serendipity works too many times!

It is starting to look like there is a well established route to 500-510 chp on a stock bottom and stock cammed LT5. And, it can be done in stages as time or $$ permits; the biggest chunk being fully porting the heads.

Anywayz...your results and mine were comparable, at that point except yours had the TB ported, and mine was not. But, I semi-ported the heads by tapering the inlet from 36mm down to the stock diameter at a point just shy of the valve guides. It crosses my mind that porting the TB might be about equal to semi porting the heads instead. (Course, BOTH would be ideal methinks: even on a top end project. Hmmmm.... sez me.)

PRIMARY PORT

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/IH8Large.jpg

SECONDARY PORT

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/IH9Large.jpg

The result was to change the personality of the car...as you well know!

Anyway...(just rambling here) I'm contemplating porting the TB now as the last piece of the porting "recipe", and it will be interesting to see what porting the TB is worth on a dyno. So, your results - sans headers and full head porting - are very incouraging!:dancing

P.

[1990 quasar blue]

Paul - you are close....

I went from 354 RWHP (baseline with flowmaster exhaust) to 392 RWHP +38 RWHP from Lees top end port.

From what I observe - it does not seem that I have left much on the table for the RWHP I am getting for the mods I have done?

I am guessing the next cheapest/easiest thing to do is headers....

I think I mentioned it before to you but those are phenomenal numbers. You're actually making 2 more hp than me and I have headers. Are those numbers sae, std, or uncorrected? Either way, great job!

[Fully Vetted]

...I'm contemplating porting the TB now as the last piece of the porting "recipe", and it will be interesting to see what porting the TB is worth on a dyno...P.

Paul, I was just having this very same conversation with Pete and Corey both yesterday. Pete is pretty sure there is something there to gain but is unsure how much since he has no before and after dyno runs to compare. Corey's thinking is that there isn't enough displacement to need it at this point and that we aren't maxing out the 58mm stock TB. I was interested in doing this as well. Like you, I'm interested to see what there is to gain, if any.

Has anyone done any "testing" of ported TB's?

[LGAFF]

Do you mean porting the air horn or installing larger throttle blades in the the TB?

My 92 has the 63mm TB, not sure there is alot to gain


I ported the air horn on this job to create somewhat of a venturi ....did the same on the one I just did.....

Mercury tested all of these items one upgrade at a time and recorded them all, one of the line managers has all the data at his home

[Fully Vetted]

Isn't the stock TB 58mm?

[VetteVet]

- Now I am fighting a "simple job" of changing the oil. Taking the easy way out allways catches up with me..... I went to "Mr Lube" last year and had them change my oil. Well the drain plug is now damaged and WAY overtight. No luck with a bolt extractor, no luck with vice grips. I'm now letting it sit with penetrating oil on it. If that doesn't help - what I am left with? - drilling it out?

Sounds like they may have galled the threads. I can't imagine that they tightened the plug so much that it won't come out with a good pair of vice grips. If the threads are galled, your only option at this point may be drilling it out to a diameter very close to the ID of the threads and then using a quality, spiral type extractor to remove it. If the threads are galled, you will have to install a heli-coil or other type of threaded insert. You should be OK if done correctly, as the sealing point is the flanged surface on the bottom of the pan. If I were close to you, I would come over and do it for you. I do stuff like this on aluminum all of the time in my line of work. If you're not familiar with this kind of work, it's best left to a professional. If things go south, you'll probably have to pull the oil pan to have it repaired.

Jep