Doc Mod Intake Install

[Bigpig455]

A cross post from V-8 Buick - I modded a spare manifold and tried it out... pretty good results but still workign out the bugs. Any advice from here is appreciated too!

http://www.v8buick.com/showthread.php?t=209741

Thanks, Rhett

Re: doctors orders

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I bolted on my "Doc Mod" intake yesterday on my bone stock 65 Gran Sport and with no tuning took it out for a few runs this morning, as timed by my G-Tech meter.

Nearest I can tell with only 4 runs under my belt, the manifold is good for .2 tenths. First run was 15.5, with mucho wheelspin on cold tires. Next two were both 15.1, one with no wheelspin but plenty of bog, the next with some wheelspin but shifting manually. Next run I matched my prior best run of 14.9, hzed the tires and shifting manually.

I was surprised that the mod didnt kill torque like I thought it would, but does feel stronger on the top end.

The one dissapointment is that it created a huge off-throttle flat spot. I get the whole "change in venturi effect" thing, and I'll admit I havent tuned for optimum vacuum yet either. But on a square bore manifold, this carb (AFB at factory settings) had immediate throttle response. It almost feels like the secondaries are dumping open too soon, but with out permanent mods I dont think I can change that on an AFB. I could try jetting/rod changes, I assume to go richer but I'm just guessing. One other aspect is it was 54 degrees out, and I put blocked heat riser gaskets in when I did the intake, but I let the car warm up thouroghly, and the choke was fully open.

Anybody have any advice? The car still runs very strong but obviously has more in it.

Thanks, Rhett

   

[Bigpig455]

Figured out my off throttle bog issue - turns out the manifold and carb need heat.. took off the blocked gaskets and put an open set on - no more flat spot.

But still something was missing in mid-range acceleration.. which I finally figured out was no trans kickdown (duh)
I didnt have power to the kickdown detent at the trans, had to break down and clean the SP/Kickdown switch at the carb linkage. Now it's got kickdown  - all the way to 60 MPH if you really boot it. THAT makes some noise!

Since those werre fixed, I threw in my new distributor, which was recurved by Carmen (10 initial, 34 total, all in by 3000 RPM, Ignitor III and Flamethrower III) and a new K&N filter and took it out this AM. Runs awesome, much more midrange power.

Took it to the "track" and it ran 14.71 @ 98.7 as measured by the G-Tech Meter. Not bad for full exhaust with manifolds and an open 3.08 diff, at least I think so.

This car ran from 15.8 to 15.6 when I got it, and having done all this in stages and documented runs along the way, I can safely say so far..

Honest tuning - Good for 4 tenths
Clutch Fan - Good for .2
Intake Modifications - .2
Distributor Recurve - .2
K&N Filter - Nothing


Going to try to make one more trip the strip at Lebanon Valley before the season ends, maybe next weekend. I'll post official times when I get back....

One tenth at a time....

Rhett

[Loren At 65GS]

Sounds like you are making some good progress Rhett, and having fun too.
Thanks for the updates.

Good luck,
Loren

[WkillGS]

You're making great progress, keep it up!
I don't recall what you are using, but I found the stock air cleaner assembly to be very restrictive. I put on a standard 14" open style air cleaner and it made a HUGE difference in the top end. Did some track testing, and it made a couple of tenths difference! BTW, I had a stock Fram filter element if that matters.
Better yet, consider a cold-air induction. That made another noticeable improvement on my car.

I'm surprised to hear adding heat to the carb helped. Conventional wisdom states keeping it colder should make more hp.....that's what I've tried to do.
But I'll keep that in mind and maybe test the 'heat' theory on my own car someday.

Keep whittling those tenths away!

[Bigpig455]

Yeah, having alot of fun (because I havent broken anything yet!)
but the rear is starting to speak up......I've got a set of 3.23's thanks to Carmen, that's this winter's project

I've got a conventional Gran Sport Air cleaner, with the snorkel baffle cut out. Interestingly, the K&N air cleaner doesnt have the rubber lip on  the top edge, so I now 've got a 1/4 inch gap all the way around that air comes in between the housing and lid, and it kinda looks cool too, if not concours.

I've been talking to "Doc" quite a bit, and his experience has been that cold intake air works great, but cold manifold does not, and thats been seconded by a few folks on V-8 Buick. Go figure, as it seems to work like a charm on Mopars and Pontiacs.....

To sum up -this car has been awesome in every respect....Bulletproof, Headturning and Fast.... Cant ask for more than that.


RT