Disappointing Numbers with t66, think I need tuning!

NickTF

NickTF

Single turbo turd.
Joined
Jun 4, 2007
Messages
5,887
stock head and cam, 887 215 pump, 6.8mm plunger lift (22.5-23*) timing, 5 x .016s 280bar, 191 delivery valves, stock holders and lines, 5k cds springs, turbonetics t66 .84 a/r divided t4 68mm exducer turbine, 4" down pipe, single 4" stack, afe stage 2 intake (6" filter inlet!), head is o-ringed with stock gasket, .020" injector sealing washers, air dog 150 supply system, goerend trans, SPEEDSHIFT'S t4 header (same as getblown5.9s) 4.10 stock gears, 265/75/16 Toyo Open Country Highway Terrain tires.

best was 484 rwhp 830 rwtq with very late peaks of 2800-2900 and 3200 respectively. Check out the attached dyno sheet and video.

I've talked to a few and am thinking too much low end fuel is the problem here. The first run had a zero plate in full back, the other two runs had the plate removed. Pretty much no change. Only posted one video given they were all virtually identical.

AFC setup at time of dyno: full forward, governor spring, starwheel all the way backed out, diaphram washers flipped.

Since the disappointing dyno I have placed the afc full back, ground the rear wahser flat too allow more rearward travel of the afc foot, placed a small washer in front of the front diaphram washer to alllow more travel, and have the starwheel in the middle of the access whole for much more tension on the governor spring. It doesn't fuel like this on the street at all any more.

I'm looking for suggestions and thoughts if i'm going in the right direction so lets hear it!

I hit the track this sunday to see if the new afc tuning helps.

http://www.youtube.com/watch?v=4lpZwHLmPyo

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I dont think its too much fuel down low, you see how much mine had down low (full cuts, gutted afc) and it still lit like fire and took off, my graph goes almost straight up as it spools.

Your graph looks to me like maybe the AFC was holding you back, but it smoked good down low so the fuel was there. its kinda baffling.
 
I suppose anything is possible.

TJ, look how much sooner yours peaked then mine though with your larger s465!!! You have me by 500 rpms or so earlier!

Wonder if your 24 valve head will just deal better with as much fuel as you were throwing to it vs. my don't breath at all 12v head?

BTW man, thanks for taking the video!!!
 
BTW, I currently have my afc setup so tight that I can feel it restrict the pedal when I mash down on it until the boost starts to build around 2000. I suppose that's normal for a tight afc setup and isn't a bad thing?
 
TJ has a cam too, and a better head;)

Front what I've seen, you need A LOT of air to make power with the factory cam with a 12v...it needs to light hard, because at 3K RPM, it's DONE!

Chris
 
Signature600 said:
TJ has a cam too, and a better head;)

Front what I've seen, you need A LOT of air to make power with the factory cam with a 12v...it needs to light hard, because at 3K RPM, it's DONE!

Chris
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Would you say the tuning is on the right path or that I need to look into a turbo setup which lights harder quicker? I have an external gate on the way, I could try a tighter a/r exhaust housing to get this t66 to come in faster and use gate to get rid of backpressure.
 
NickTF said:
BTW, I currently have my afc setup so tight that I can feel it restrict the pedal when I mash down on it until the boost starts to build around 2000. I suppose that's normal for a tight afc setup and isn't a bad thing?
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Im baffled unless you dont have something right in the AFC, If you go tight with that spring you will lose travel. Ever apply air to it on the bench with it off when adjusting?
 
With the starwheel all the way backed into the housing 48psi is what it took to move it full forward. With it setup like it is now I haven't checked it but i'm sure it's alot more. With the heavy tst spring it was like 30psi (starwheel backed all the way out) and 22ish with the light spring.
 
Maybe this weekend I'll make a pass with no afc arm in it at all just to make sure. Obviously I will have to be very easy with the peddle with no fuel control in it!

I don't think that's the problem though, because when I put the 2095 rack plug in it was definitely hitting it because of super duper amounts of smoke, loss of boost, and generally poorer wot performance. As soon as I removed the rack plug the boost came back and the better wot performance returned. In other words it was hitting the plug with the afc set like it was on the dyno.
 
NickTF said:
BTW, I currently have my afc setup so tight that I can feel it restrict the pedal when I mash down on it until the boost starts to build around 2000. I suppose that's normal for a tight afc setup and isn't a bad thing?
Click to expand...

when you mash down on it is it very smokey? try sliding the housing foward a little bit
 
94 12valve said:
when you mash down on it is it very smokey? try sliding the housing foward a little bit
Click to expand...

It is still smokey, not like in the video, but there is pre-boost smoke. Looking at videos from this sunday will enable better qauntifying of this though. This 215 pump really puts out some fuel right off idle, seems a lot different then even the stock 180 I had!
 
Yeah, it didn't seem so during that dyno! Overfueling may be the cause it could be the big header/manifold. Plan to try again with a stock type manifold if I can get Weston moving:p
 
IMHO, Run what feels best on the track and street, if it runs the times on the track that you are looking for; what does the dyno number matter?
 
Any idea what kind of boost numbers you saw on the dyno? How are they compared to what you see on the street? Have you ever driven the truck without the AFC arm in? I suggest taking the foot out and giving it a quick test drive to see if it feels any different. I have ran my puller without an AFC a lot on the street. I actually prefer it sometimes. Just have to learn to be easy on the throttle.
 
NickTF said:
The first run had a zero plate in full back, the other two runs had the plate removed. Pretty much no change.
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This leads me to believe that your AFC might be set too tight. No reason you shouldnt see a difference with the plate full back vs. the plate out.
 
teddybear said:
This leads me to believe that your AFC might be set too tight. No reason you shouldnt see a difference with the plate full back vs. the plate out.
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You're right man, but at the same time if the afc was the issue I'd think I wouldn't have noticed any difference in running a 2095 plug vs. the stock one. I am certainly open minded to this possibility though and like I said, may likely make a pass with no arm in and see what I get!!!
 
Turbonetics, sent us a bunch of turbos to test through mid 2008. We never had any impressive results with their 66, or an experimental 61. About 40 psi boost from the 66 is all we could get.
 
WICKEDDIESELS said:
Turbonetics, sent us a bunch of turbos to test through mid 2008. We never had any impressive results with their 66, or an experimental 61. About 40 psi boost from the 66 is all we could get.
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Could you describe the 66 more and what combination it was on?
 
Sorry, forgot to add that we saw about 45psi on the dyno, I see a max of 50 on the street and not till about 3000rpm. this is with between 68 and 70psi drive pressure.
 
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