Project: Make a slow GTI a little less slow

[Mowgli87]

I guess it's about time I start an official project thread for my old kraut box. I've had the car for over 1.5 years, and I'm just getting around to doing serious mods. :rolleyes:

Little background:
1986 VW GTI 8V 5 spd
When I acquired the car, it was bone stock with HUGE ghetto ass black/chrome accent wheels. I swapped those for a decent set of OEM BBS meshies wrapped in Falken Azenis.

When I got it:
http://i39.photobucket.com/albums/e156/Mowgli87/mk2%20GTI/DSCN1772.jpg

After BBS install:
http://i39.photobucket.com/albums/e156/Mowgli87/mk2%20GTI/28314_445799284777_507539777_5790442_4998402_n.jpg

After a couple months of getting used to the car, I realized the desperate need for a small suspension overhaul. I ordered all new bushings for the front suspension and upgraded a few of them in the process. I also rebuilt the shifter with all new linkages and bushings to get rid of the phantom first/reverse syndrome. The results were shocking. It was like a completely different car. It was at that time when I realized how much fun this little guy really is. It may not have much power, but the challenge of keeping momentum through a nice twisty road makes the car a blast to drive.

Also, this is the only FWD car I've ever driven that doesn't plow like a bulldozer. It probably helps that I came from a mk4 GTI, but nonetheless this thing just bites the ground and GOES!

So enough intro... here are my plans for this car:

For now I'm just treating it as a street prepped NA 8V, using the following mods to realize that:

Currently working on:
Mildly ported head
Autotech 270 Cam (.050" more lift and ~ 10 degrees more duration... I forget what the changes in overlap are)
Titanium valve spring retainers
New HD valve springs
Adjustable cam gear
Dual port exhaust manifold and down pipe (OEM upgrade over "toilet bowl" manifold)

I might also throw in HD motor and trans mounts.

Future Plans:
I have begun acquiring parts for more suspension upgrades also. They include:
Bilstein Sport dampers (have the front, need to get rears)
H&R Sport springs
All poly, delrin, or HD rubber replacement bushings

I'm kind of undecided on final plans for the outcome of this car. It could turn into a track car after graduation, or it could remain a daily. For now my main goal is to have a fun reliable daily driver that I can take to regional auto crosses and maybe a couple track days. I'd like to keep it somewhat tame, but I'm very likely to boost it eventually.

Ultimately, I would like for this car to fit the following bill:

~ 200 whp
less than 2200 lbs
Fuel economy in the mid to high 20's
Comfortable enough for daily duty (doesn't have to be really nice, just not completely raw)

To reach those goals I could take a few different routes:

Potential future plans:
small-ish turbo on the 8V
Mega squirt engine management

OR

Turbo 16V swap

OR

mk4 2.0L 8V swap
High compression ITB setup making around 160 whp

OR

stock 1.8T or stock VR6 swap

I'll update this later with some more pics, but I have to get back to work.

[easy2speed]

I've always liked those cars. I'm interested in seeing how it turns out. You should do a before and after dyno.

[Veedubtrek]

Awesome man, looking forward to the pics and updates!

[Mowgli87]

I've always liked those cars. I'm interested in seeing how it turns out. You should do a before and after dyno.

Unfortunately, I didn't get a before dyno. I know, shame on me. I'll never know exactly how much I've improved over the stock configuration. I did get a stock 1/4 mile time though. A smoking 18.2 @ 74 mph!!! WOOOHOOO!!! :D :D

However, this motor is somewhat of a test bed for me to hone my skills at the black arts of old school engine building (e.g. porting, exhaust and intake tuning, increasing compression, etc.). I say black arts because it seems that people now days just send their car to so-and-so experts to get stuff done. I'm doing all of this myself.

[Jess]

put a turbo on it and fuck everything else.

[AadosX]

^ this and.. I liked the old wheels better lol. :D

[roadracer4life]

put a turbo on it and fuck everything else.
+1

[Mowgli87]

I figured I'd get bombarded with the turbo comments. :D You guys are pretty predictable.

I do want to turbo it eventually, but not until after I fix an oil burn issue I had been battling. I don't have conclusive evidence, but I'm pretty sure the valve stem seals were leaking. They were certainly crispy enough to allow a little leakage. The current stage of mods is nothing more than me taking advantage of rebuilding an old tired cylinder head. I figured, "while I'm rebuilding it, I might as well try to let it breathe a little better." Then when I do slap a turbo on it, it'll just be that much more effective.

I'll try to sit down sometime this weekend and start my documentation procedure. I have been going in stages, taking flow measurements between each step. I've also been taking quite a few pictures.

[Swine]

I figured I'd get bombarded with the turbo comments. :D You guys are pretty predictable.

I do want to turbo it eventually, but not until after I fix an oil burn issue I had been battling. I don't have conclusive evidence, but I'm pretty sure the valve stem seals were leaking. They were certainly crispy enough to allow a little leakage. The current stage of mods is nothing more than me taking advantage of rebuilding an old tired cylinder head. I figured, "while I'm rebuilding it, I might as well try to let it breathe a little better." Then when I do slap a turbo on it, it'll just be that much more effective.

I'll try to sit down sometime this weekend and start my documentation procedure. I have been going in stages, taking flow measurements between each step. I've also been taking quite a few pictures.

If it makes more power n/a itll make even more power once turboed(duh? lol). Looks good.

[Mowgli87]

If it makes more power n/a itll make even more power once turboed(duh? lol). Looks good.

Exactly! :D

Anywho ... on to the build process.

Like I said, I've been doing the port work in stages. So I'll just start going through them.

Here is what the head looked like immediately after it came off the block.

https://lh5.googleusercontent.com/-ZtytCOqgkFo/Tgd6ufUw4AI/AAAAAAAABC0/AUppgHyIptQ/s640/2011-05-18%25252017.17.54.jpg

https://lh5.googleusercontent.com/-nLCVL9CBaBs/Tgd6zGXlw1I/AAAAAAAABDE/o9y4iIC1lOo/s640/2011-05-18%25252017.18.06.jpg

https://lh3.googleusercontent.com/-L29jZgNSSxM/Tgd63p31UpI/AAAAAAAABDM/wRmLIUfNMwY/s640/2011-05-18%25252017.18.23.jpg

It's a little dirty, but overall I think everything looks ok for a 25 year old cylinder head. The next day I took the head to Carquest to get them to clean it. I forget if they used acid wash or steam clean, but whatever they did the head came out looking great!

Time to get to work!

Stock:

Before I did anything I got flow measurements for stock intake and exhaust. I'm assuming most of you guys understand the basics of how flow benches work, so I'll skip the details. Our flow bench is smaller than what most people use for projects like this. For the entire project I have been comparing flow measurements at 15 in-H2O pressure drop. I took 9 measurements from 0.050" valve lift all the way up to 0.450" (max lift for my new cam) in 0.050" increments.

Flow bench:
<a href="https://picasaweb.google.com/lh/photo/qEx9qemrKbFag6_rki1gpg?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/-sDUffqUBTmw/Tgd58swSNGI/AAAAAAAABCI/y0iEDwzj1Tw/s640/IMG_3588.jpg" height="427" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/V4GaPFwPJOnA0_5T7PxILA?feat=embedwebsite"><img src="https://lh3.googleusercontent.com/-Kn31cy0cwD0/Tgd5_Y7SfnI/AAAAAAAABCM/a8xJunHBPBc/s640/IMG_3590.jpg" height="427" width="640" /></a>

The "stock" results below were measured before I even cleaned the soot from the ports out. I wanted to see exactly where the head was coming from in it's original (to me) condition.

Valve Lift (in) - Intake Flow (CFM) - Exhaust Flow (CFM)

0.050 - 12.8 - 11.6
0.100 - 28.4 - 27
0.150 - 44.7 - 41.8
0.200 - 57.2 - 51
0.250 - 66 - 54.8
0.300 - 71.1 - 56.7
0.350 - 73.7 - 58
0.400 - 76.6 - 58.8
0.450 - 79.1 - 59.4

[Mowgli87]

UPDATE: My previous post has been updated with a few pictures.

Being on the Auburn FSAE team definitely has a few perks. So far I've been able to do all of this work in the comfort of a climate controlled shop. I also have access to some decent tools (primarily the air tool that I'm using), and good, steady compressed air supply.

Tools:
<a href="https://picasaweb.google.com/lh/photo/HKmAmDxKLz9smQ9C73a1_w?feat=embedwebsite"><img src="https://lh6.googleusercontent.com/-53OwW6_bs3s/Tgd6FDB-2FI/AAAAAAAABDk/mHY3SMJzhkk/s640/IMG_3623.jpg" height="640" width="427" /></a>

Work Space:
<a href="https://picasaweb.google.com/lh/photo/0xuTnVcV-9LJ_kTw_Jmk_Q?feat=embedwebsite"><img src="https://lh6.googleusercontent.com/-s22V_DPCaaE/Tgd6Meh9jyI/AAAAAAAABCY/XuXwSw-61hI/s640/IMG_3607.jpg" height="640" width="427" /></a>

<a href="https://picasaweb.google.com/lh/photo/zN2jHbsjDYwpFHjABDLdxw?feat=embedwebsite"><img src="https://lh5.googleusercontent.com/-x5wdGzPiIWY/Tgd6Vaaw5NI/AAAAAAAABCk/g9QX1R9_8aw/s640/IMG_3609.jpg" height="427" width="640" /></a>

On to the porting...

Intake Stage 1:

The first stage of the intake porting was primarily focused on opening up the port entry to match the intake manifold gasket. In the picture below, you can see that the gasket is a good bit larger than the actual port. I simply set the gasket up to the port and made some scribe marks for reference. I tried to focus on removing material from the top of the port more than just an even amount all the way around the opening. My intention was to allow the air to have a little more of a straight shot from the manifold to the valve. For the rest of the port I just blended the floor and the walls down past the casting marks.

https://lh3.googleusercontent.com/-LBVbpc1ajNE/TeJdg6eljgI/AAAAAAAABAU/q9Dyv-_sDk0/s640/2011-05-23%25252023.57.03.jpg

Since this area is so big, I didn't want to just go by look and feel alone, so I took some measurements to keep track of the port gemetry. I measured the length and width of the port at three different depths (9 total measurements) for each port. Another thing this allowed me to do was make sure I didn't eliminate the taper of the port that leads up to the throat area. I had read of many first timers cutting too much material out, and subsequently killing all of the intake charge velocity. I got the measurements to within .005" across all ports. I think that is gonna be good enough for even flow across the cylinders, and the flow results proved that it helped the air move a little bit better. My hopes for the rest of the project had officially been secured. I had proven that I'm capable of making at least small increase in flow. :thumbsup:

<a href="https://picasaweb.google.com/lh/photo/VomJhHViRc4VVq6dFhiQLg?feat=embedwebsite"><img src="https://lh6.googleusercontent.com/-MSQfzKnk60U/TfAlrng73JI/AAAAAAAABAw/f8tUHtZqqH0/s640/IMG_3606.jpg" height="427" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/M1Pl-oGlOwVF6HfScX7OzA?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/-UDKzb3UjDkM/TgeQ3OH8pcI/AAAAAAAABD0/hqS4pwQu0qw/s640/IMG_3627.jpg" height="427" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/tzod1s2RAl6j9-DVT7rClA?feat=embedwebsite"><img src="https://lh5.googleusercontent.com/-utu4A9Kc274/TgeQ73HC9mI/AAAAAAAABD4/a6BDnI3H1GA/s640/IMG_3625.jpg" height="427" width="640" /></a>

[Mowgli87]

I'm about to just dump the rest of the project in the next couple of posts.

Intake Stage 2:

My focus moved from the port entry into the bowl and throat area. The stock head had a few spots with sharp edges and ridges in the bowl area. I cut those down and blended them in to the lower parts of the bowl.

Stock:
<a href="https://picasaweb.google.com/lh/photo/FoP1tYYLLvi6hd2gf6acKg?feat=embedwebsite"><img src="https://lh6.googleusercontent.com/-eC_pa-Csb6g/TfAlmqjjIfI/AAAAAAAABAo/LbEeJiL6X2E/s640/IMG_3635.jpg" height="427" width="640" /></a>

Ported:
<a href="https://picasaweb.google.com/lh/photo/KjPjAa5ND5Gr6xtssnLvpA?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/-0wx05OOV2fc/TfAlpEgPWlI/AAAAAAAABAs/hrybu63BAow/s640/IMG_3637.jpg" height="427" width="640" /></a>

For the throat I tried to minimize the material removal so velocity would stay up. I rounded the short side radius to remove a sudden "drop off" into the bowl.

Stock:
<a href="https://picasaweb.google.com/lh/photo/mjo_g22dCNm8Qo0uE_tXUw?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/-c12H-r3tIXk/Tg9CbhLaBVI/AAAAAAAABE0/C0wej7Q8ags/s640/IMG_3640.jpg" height="427" width="640" /></a>

Ported:
<a href="https://picasaweb.google.com/lh/photo/beKsd5hAoDNgv7SvZUHzvA?feat=embedwebsite"><img src="https://lh5.googleusercontent.com/-PtHchQ4xZB8/Tg9CbFn9MkI/AAAAAAAABEw/dA1okw23QCU/s640/IMG_3639.jpg" height="427" width="640" /></a>

Flow bench results showed a slight step backwards, which took me by surprise. However, I was still flowing better than stock, so I kept going with more stages.

Intake Stage 3:

The only thing I did for stage 3 was streamlining the valve guide bosses. The stock bosses protruded a pretty good distance into the cylinder. And they just seemed to be restrictive. Rather than completely cut it down flush like some people do, I just cut the sides down to the valve stem. I blended the valve stem into the guide boss also.

Stock:
<a href="https://picasaweb.google.com/lh/photo/PGn6weVngtvTJPobnn1tWg?feat=embedwebsite"><img src="https://lh6.googleusercontent.com/-B0B_BDJkiMA/TfAl-hiPkJI/AAAAAAAABA0/T4noMJpJjAE/s640/IMG_3651.jpg" height="427" width="640" /></a>

Ported:
<a href="https://picasaweb.google.com/lh/photo/CAWU_8nzWU15SAQR_Zq3aw?feat=embedwebsite"><img src="https://lh5.googleusercontent.com/-tOJHobXpUbw/TfAmAVQbtBI/AAAAAAAABA4/YFqBEmXsqnI/s640/IMG_3652.jpg" height="427" width="640" /></a>

This step brought flow at all valve lifts back into check. Increases were made all the from low to high lift. Confidence reacquired! :D

Intake Stage 4:

I realize in hindsight that I should have flipped the order of my stages around. This last stage should have come first, but I guess it doesn't really matter now.

For this stage I just cut the back side of the valve back to a 30* angle (stock was 45*). My intention was to allow the air to have a smoother path into the port by cutting out a sharp edge. I also took the opportunity to turn the lathe to high speed so I could clean the valves a bit more.

<a href="https://picasaweb.google.com/lh/photo/jcu-YqkY_fKfxfC-0_50iw?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/-zj2j8qAap5U/Tg9MBbBHDYI/AAAAAAAABFM/F7tjJtBDjds/s640/IMG_3669.jpg" height="427" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/pZxbgZ1syxr47TJZ5Q2GqA?feat=embedwebsite"><img src="https://lh6.googleusercontent.com/-AEEuKNTov58/Tg9MGtVw6eI/AAAAAAAABFU/Q-2FF2mBIqQ/s640/IMG_3664.jpg" height="427" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/QXrJ4i1dhz2b-YOWv_O3jA?feat=embedwebsite"><img src="https://lh3.googleusercontent.com/-VU15mrQrWcU/Tg9MEi4BxHI/AAAAAAAABFQ/nHnpa_riNoc/s640/IMG_3680.jpg" height="427" width="640" /></a>

[Mowgli87]

I guess I should finish the documentation part of this, considering I've been driving the GTI since Tuesday. :D

Exhaust Stage 1:

I started the exhaust similar to the intake. I just smoothed the casting surface from the port walls and cut the short radius down to a consistent radius.

I actually didn't get before pictures of just the stock exhaust ports. However, you can still see the general condition from the pics of the intake ports.

I saw a drastic improvement in flow from mid range all the way up to max lift. I'm not really sure if it was just from getting it clean or if it really was that restrictive initially.

<a href="https://picasaweb.google.com/lh/photo/_40qWuDBp9PoyQu1h9CV2g?feat=embedwebsite"><img src="https://lh3.googleusercontent.com/-Np228-_5b8k/TiI3-_85mMI/AAAAAAAABGE/TKAebC_Fblo/s640/IMG_3601.jpg" height="427" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/rWtpvgDaPxN1aSUuwiIbBA?feat=embedwebsite"><img src="https://lh6.googleusercontent.com/-FIebeyws6n8/TiI4JHyjaQI/AAAAAAAABGI/nVSv5Bywei8/s640/IMG_3754.jpg" height="427" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/CXe5xLIQIY-vE5sfiI18yw?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/-JqooJB7Mj0E/TiI4ln5PfuI/AAAAAAAABGU/te-19Pzh32Q/s640/IMG_3764.jpg" height="427" width="640" /></a>

Exhaust Stage 2:

This stage consisted of rounding off the sharp edge near the valve seat and also removing a little bit of a hard edge above the seat (combustion chamber side). My intention was to allow the exhaust to slip by the valve with less restriction from sharp edges. I basically cut material out all the way up to the seating surface. This stage actually brought up the mid range flow a little bit in addition to the top end for this stage.

<a href="https://picasaweb.google.com/lh/photo/kquNLM4BzwHz0P3Hyselvg?feat=embedwebsite"><img src="https://lh3.googleusercontent.com/-Z1ZDp1535uU/TiI7QjdaayI/AAAAAAAABGs/IlZMYOXWX7k/s640/IMG_3771.jpg" height="427" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/_6kCgwPqJGT1Dy2PfSjR0w?feat=embedwebsite"><img src="https://lh5.googleusercontent.com/-d_lRBXAn8vk/TiI7QCYKXUI/AAAAAAAABGo/Q_hsYEYXZ0s/s640/IMG_3779.jpg" height="427" width="640" /></a>

Exhaust Stage 3:

As with the intake I streamlined the valve guide boss to get rid of a little bit more restriction in the port. The results showed a slight improvement over the entire valve lift range.

<a href="https://picasaweb.google.com/lh/photo/p_-sIuWuBIU7cLKj1o2n9A?feat=embedwebsite"><img src="https://lh3.googleusercontent.com/-AeQgExNExzo/TiJAisRG3yI/AAAAAAAABHs/nMixWiVQVUM/s640/IMG_3630.jpg" height="427" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/xnrslNoA72kI-NMzn1CKgw?feat=embedwebsite"><img src="https://lh5.googleusercontent.com/-6mo4cBsVEt0/TiI-uxWDkUI/AAAAAAAABHQ/NttxwuNXxqk/s640/IMG_1776.jpg" height="427" width="640" /></a>

Exhaust Stage 4:

The last stage for exhaust was the same as the last stage for intake. I cut the valve back and I also added a small radius to the lip of the valve to allow air to slide around the edge on it's way out of the cylinder. On the back cut I didn't necessarily add a specific angle as much as I just smoothed the edge. Unfortunately I didn't get a picture at all of the stock valve profile. However, I did draw out on paper the steps I took on the lathe. The final step brought the flow up a little at the very bottom and top of valve lift.

<a href="https://picasaweb.google.com/lh/photo/DgF_XZScVcFvO4piTnKLDw?feat=embedwebsite"><img src="https://lh6.googleusercontent.com/-2nu4zOx59uE/TiJDL3ywnaI/AAAAAAAABIM/JQ826U2J1Ns/s640/2011-07-16%25252021.02.12.jpg" height="480" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/G4i9UPlPVKiSEc9jhYjWKA?feat=embedwebsite"><img src="https://lh3.googleusercontent.com/-a7118JmI1TU/TiJDqKuUqtI/AAAAAAAABIQ/vjbpIY0Wls0/s640/IMG_1764.jpg" height="427" width="640" /></a>

[Mowgli87]

The car is now back together, and I've been driving it for about a week. Initial impressions are not as impressive as I had hoped, but I can definitely feel an increase in breathing ability up at the top of the power band. Where the car used to fall on it's face after about 5,000 rpm it now just keeps pulling into the 6k range. I think the timing might still be a tick off, so I'm gonna withhold final judgement until I make sure it's good. I do have the adjustable timing pulley on the car now, so it could just need a tweak.

Overall, I'm really glad I went through with this project. If I gain nothing else at all, I have added another skill to my collection. And I can fully appreciate the level of effort and the asking price for a professionally ported cylinder head.

Results!

I know you guys would love to see before and after dyno charts, but I didn't get a baseline. Shame on me, I know. I do have the next best thing though. Here is the breakdown of air flow for each stage and a couple fancy charts to show the comparisons. :D

<a href="https://picasaweb.google.com/lh/photo/4rF1foA97nG6M6c_rmjkSw?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/-sfcM-hD8N_4/TiJFYSqkvqI/AAAAAAAABJY/lsialhqxUH0/s640/Flow%252520Data.jpg" height="576" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/mS6IUqjIzwwx74PsVvFSSQ?feat=embedwebsite"><img src="https://lh3.googleusercontent.com/-N5NuIdV3D6U/TiJHXOv8FYI/AAAAAAAABJQ/M69sUmldHtE/s640/Intake%252520Flow%252520Chart.jpg" height="427" width="640" /></a>

<a href="https://picasaweb.google.com/lh/photo/w9dCKETs8_CxxGXizrHvMw?feat=embedwebsite"><img src="https://lh5.googleusercontent.com/-wBAjTFFoqPE/TiJHWjW86CI/AAAAAAAABJM/BRgyaXXwlNM/s640/Exhaust%252520Flow%252520Chart.jpg" height="442" width="640" /></a>