Whaaatt !! not another intake mod (Page 1/4)
sleek fiero DEC 11, 09:02 PM
I was out in my shop a while back and thought why don't I modify my intake on my 85GT to take a larger Throttle body and fix the choke spots in these factory intakes. I already increased from 52mm stock Holley TB to a 54mm Bosch Motorsports TB. But as we all know bigger' faster, better. I was having problems posting this thread and will try to post this before continuing
Patrick DEC 11, 09:05 PM

quote
Originally posted by sleek fiero:

I was having problems posting this thread and will try to post this before continuing



...and, and, and?

sleek fiero DEC 11, 09:30 PM
Yahoo It finally worked. So I started by searching for a donor upper manifold and thanks to Tristen who went to a lot of trouble to get it shipped to me I now had a base to work from. This is my original intake on the car


and this is the donor manifold

So first I built an adaptor plate to fit my new 60mm Bosch Motorsport TB. cut out of 1/2" aluminum plate.

Then I built a jig to hold everything in place for fitting and welding. you can see her how big the new TB is compared to the original mounting plate.

And then I took my grinder with a zip blade and cut the manifold apart retaining the bottom of the inlet runner to keep the EGR port which I use for my Bosch MAP sensor

Sorry I have run out of time to finish this but will continue soon
sleek fiero DEC 11, 09:34 PM
And yes Patrick I will finish this. surprised that you would be interested in this mod.
Trinten DEC 11, 09:54 PM
I was glad to send it to someone who was going to put it to good use!

... plus it's so awkwardly shaped, it was taking up a bizarre spot in my garage. lol. So I have room to put a whole storage tote there now.
Patrick DEC 11, 10:02 PM

quote
Originally posted by sleek fiero:

And yes Patrick I will finish this. surprised that you would be interested in this mod.



I'm surprised you're surprised!

I've long been aware of the bottleneck in the factory intake. It was a local club member who came up with the original DAWG modification years ago. I've always been interested in seeing how this restriction has been overcome.
sleek fiero DEC 11, 11:47 PM
Yes I've seen the dog mod and I am sure it works for the squashed area where the pipe meets the plenum. I am addressing that and more. My goal was to get rid of the 120 degree bend for the #6 intake runner. sorry I got the photos mixed up. The one photo show some of the fitment work on the pipe. The first picture I circled the bad corner into #6. I bought a new TIG welder and it has some different procedures compared to what i am used to so it took some serious practice to get some decent welds as this next photo shows.

It took quite a while to do all the fitting and welding as there were 11 pieces all together.

I did some tapering and polishing to blend the mounting plate to the pipe and ground all the factory flashing lines and polished the whole exterior.

I cleaned inside and out and prepped it for paint. Here is a tip for you I use VHT caliper red paint . It is as tough a paint as you can find the colour is as close to perfect match as you can get and gas and oil don't bother it.

And here I am checking the fit of the 60mm TB
[img]https://images.fiero.nl/userimages/sleek%2520fiero/IMG_4549.jpg[/img
I will post more when I install it. I am also going to do the cold air pipe in the wheel well. My air cleaner housing has been modified on the outlet already and a K&N filter installed.
sleek fiero DEC 11, 11:53 PM
Some of the pics don't come through. I'll try that last one again.
Patrick DEC 12, 01:53 AM

quote
Originally posted by sleek fiero:

Some of the pics don't come through. I'll try that last one again.



The last bracket after [/img is missing.


quote
Originally posted by sleek fiero:

Yes I've seen the dog mod and I am sure it works for the squashed area where the pipe meets the plenum. I am addressing that and more.



I believe part of his goal was to open up the restriction while retaining the factory appearance of the intake when viewed after installation (good for collector plates)... but yeah, no doubt the air flow can be improved upon even further.

CLICK FOR FULL SIZE

With your reassembled/modified intake, were you able to smooth out the interior passages where the added material was added/welded?

[This message has been edited by Patrick (edited 12-12-2023).]

sleek fiero DEC 12, 10:29 AM
Yes the interior is pretty clean. I had one "grape" in the neck which was easy to reach with my die grinder. The rest I could inspect with my bore scope and it looks good. I was very careful to keep the weld penetration to a minimum. By the way it isn't #6 intake runner that got opened up 'it was actually #3 runner. That was the most important change as the corner was so sharp. sleek