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Re: Taco's 4KTQ 20vt Swap: The Red Baron - Parked....for now
Posted: Sun Oct 27, 2013 8:56 pm
by 40v4kq
Could spacing the pressure control regulator away from the block a little help possibly? Sounds like a could be getting heat soaked.
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Parked....for now
Posted: Sun Oct 27, 2013 10:30 pm
by AngryTaco
I had already tried a new wur. No change and I spaced it away.
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Parked....for now
Posted: Mon Oct 28, 2013 10:42 am
by GTJeff
Did you ever check the o-rings in the pressure regulator inside the fuel distributor?
Also, this is a long shot but how much air flow metering plate free play do you have? It should lift up 1 to 3 mm before any resistance is felt. If you have zero free play then the system could leak down.
When checking residual pressure try connecting the pressure gauge to the line going to the cold start injector. You may not be getting correct results connecting the gauge to the WUR line.
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Parked....for now
Posted: Mon Oct 28, 2013 11:16 pm
by AngryTaco
Not yet. Been too busy with school.
Ill be looking at it tomorrow since I got the car in the garage now
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Parked....for now
Posted: Tue Oct 29, 2013 2:32 pm
by viridia
I have good residual pressure and hot start issues (typically >2 bar after 24 hours). Maybe we have two different problems, though.
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Parked....for now
Posted: Fri Nov 01, 2013 1:50 pm
by AngryTaco
Interesting. I pulled the control pressure reg setup out of the fuel distributor and the oring is fine. Im grabbing an entire fuel distributor setup this weekend from the junkyard and am going to replace components to see what happens
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Parked....for now
Posted: Fri Nov 01, 2013 11:56 pm
by AngryTaco
I honestly suspect that the frequency valve is the culprit. I was also closely inspecting the control pressure reg valve and I noticed that the shaft had a lot of play in it which would result in leaking. Ill know more tomorrow
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Parked....for now
Posted: Sat Nov 02, 2013 11:53 pm
by AngryTaco
OK....SOOOOO. I believe I have fixed my hot start issue................!!!
I changed the oring in the fuel dizzy control pressure reg plunger to a viton oring. The original one didnt look to be in bad shape but I decided to change it anyways.
Then I changed out the fuel frequency valve with one I grabbed out of the local yard. On the first turn of the key, the SOB fired IMMEDIATELY up even though I had drained fuel out of the system replacing things. Its never done that before. Then I ran the hell out of it. Still having the boost issue where I lose all boost pressure until I reset the pedal and go again.
Then I let the car idle until the fan came on. Shut it off and let it sit for 20 mins. I'll be damned but the damn car fired right up and I didnt have to sit there and crank it over.....I'll play around with it some more tomorrow or during the week.
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Sun Nov 03, 2013 6:36 pm
by AngryTaco
Also noticed I now have a boost flutter issue. Surge if you will. However when I unplug the wgfv, the flutter goes away but will maintain boost. Still does weird issue if I boost too high. Im concluding that the cis just cant keep up at this point
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Wed Nov 06, 2013 3:35 pm
by AngryTaco
So sometime in the spring Im going to be swapping pistons again. Im going to throw a set of AAN pistons in but there is a small problem. The wrist pin is a 20mm compared to the 20vt 22mm wrist pin. Im not using 20vt rods because they are weaker and the rod bearings are smaller too.
My question is if anyone has ever heard of boring the piston wrist pin boss out to accomodate a bigger pin?
Since its a free floater, I dont think worrying about interference fit is required
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Wed Nov 06, 2013 3:52 pm
by dana
wont you end up with some very non turbo friendly compression with AAN pistons? or are you planning a 20v head as well.
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Wed Nov 06, 2013 4:20 pm
by vt10vt
dana wrote:wont you end up with some very non turbo friendly compression with AAN pistons? or are you planning a 20v head as well.
E85
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Wed Nov 06, 2013 4:24 pm
by dana
what is a realistic compression number for e85? Kinda wish we had that shit around here when I was planing with fast cars.
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Wed Nov 06, 2013 4:30 pm
by AngryTaco
Ill end up with 9.3:1 compression. Deck heights are the same if I remember correctly
Edit: now that I think about it, I would end up with more than 9.3:1 due to less chamber CC in the 20vt head
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Wed Nov 06, 2013 4:31 pm
by AngryTaco
dana wrote:what is a realistic compression number for e85? Kinda wish we had that shit around here when I was planing with fast cars.
Since the octane rating is about 108, MOAR would be the answer lol. But seriously, about 10:1
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Wed Nov 06, 2013 5:45 pm
by dana
AngryTaco wrote:
Edit: now that I think about it, I would end up with more than 9.3:1 due to less chamber CC in the 20vt head
thats what i was thinking
10:1 with a turbo would be awesome. Biggest downside of a turbo motor is its low compression and lack of balls off boost
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Thu Nov 07, 2013 12:25 am
by AngryTaco
Yeah but remember with a 20v the trick is maxxing out your flow potential. When you reach max flow the head and manifolds will support, you have to increase compression for more power. Most Ive seen is 10.5:1 on a 20vt with e85 making over 500hp
But now you start running into detonation issues. I figure with the right camshaft, e85, w/m, a good tune, and a bit more port work, Ill see 425 crank hp on VEMS with pump on the 2.2L setup (current motor). 10.5:1 compression with a stroker 2.5L....maybe over 600 if the thing doesnt explode on e85
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Thu Nov 07, 2013 11:12 am
by AudiSport4000
Dyno numbaz?

Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Thu Nov 07, 2013 12:46 pm
by AngryTaco
Sooooon. There wasnt a dyno at BBQ
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Thu Nov 07, 2013 1:28 pm
by GTJeff
Isn't the wrist pin higher up on an AAN piston? I thought that AAN/3b rods are longer than MC rods?
If AAN pistons could be made to work with MC rods/crank wouldn't everybody be doing it on their Ghetto 20vt builds?
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Thu Nov 07, 2013 2:48 pm
by AngryTaco
Well like I said, the wrist pin diameter is different too. Im keepibg everything 20v. Why? Because
I doubt most ghetto swap guys would want to go through all the bs Im going through
And im fairly sure all early 5 bangers are 144mm rods
Also does anyone know of any cars that came with an airplate bigger than the 5-cyl turbos? Its just a curiousity thing and Im seeing if I can make just a tad bit more power out of the cis
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Thu Nov 07, 2013 5:38 pm
by GTJeff
And im fairly sure all early 5 bangers are 144mm rods
My understanding is all MC's have 136 mm rods.
http://www.not2fast.com/vw/stuff/vw_engines.shtml
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Fri Nov 08, 2013 12:34 am
by AngryTaco
Yeah I saw that too and I thought that was really weird. Ill have to measure. If indeed the rods are different, then custom pistons it is! That or Ill just throw a 20v crank in
Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Fri Nov 08, 2013 12:12 pm
by AngryTaco
So plans for the weekend is the following:
Drop passenger front strut and get rid of bad hub.
Maybe fabricate up a triangular light bracket to mount 6 lights on the front bumper. Start wiring

Re: Taco's 4KTQ 20vt Swap: The Red Baron - Hot Start...Fixed
Posted: Fri Nov 08, 2013 12:55 pm
by bradyzq
AngryTaco wrote:Yeah I saw that too and I thought that was really weird. Ill have to measure. If indeed the rods are different, then custom pistons it is! That or Ill just throw a 20v crank in
20V crank?