Project: Limpwrist (project logs keep me motivated)

[rockthemullet]

Project: Limpwrist (Updated 05.15.09)

Some super recent (as in yesterday) pics of the Cobra.

I couldn't find a tape measure, who cares. I pulled the blower so I could clock it for this:

So far I'm trying to set it up so that there is a single piece of pipe from the supercharger to the driver side of the IC, all welded. There will be two separate pieces from the passenger side of the IC to the throttle body, due to ease of removal. In all honesty, I could probably make that one piece too but I don't want to pull my front bumper if I want to pull that pipe out of the engine bay, haha.

Both ends of the IC and the joint between the two passenger side pipes will see 3" aluminum vband setups. The supercharger and throttle body joints will use the only silicone.

I am converting from draw through to blow through. The MAF will be in the engine bay instead of the fender well, which is where it was with the a/w setup. I'll be running a wastegate and a blow off valve, both before the IC and both concealed behind the front bumper.

I am also converting to an 8-rib setup (from a 6 rib) and pullying down to a 3.1" (from a 3.33"). So, if anyone here has some 5.4L F-150 pulleys laying around, let me know!

~Eric

 

[outlawdan]

nice!

 

[rockthemullet]

Thanks man! I noticed yours, looking forward to your progress as well.

 

[rockthemullet]

TUBING!!!

Here they are out of the car...

I suppose they look relatively simple but it took a lot of time to make them look simple, if that makes sense, lol.

Behind the bumper...

Here's the difference between a 6-rib (alternator) and 8-rib (blower). 33% more belt traction. Woot.

~Eric

 

[dirtybird]

Nice! Can't wait to see some pics/vids when it's done!

 

[rockthemullet]

Thanks man, neither can I!

Well it doesn't seem like there's much interest on this project but I'll keep updating anyway...

MORE TUBES!!!

A buddy of mine got them tigged up last night. I cleaned up the weld areas today on my lunch. Not sure if you guys can tell but the center section of the pipe with only two welds was scuffed up real quick with a brillo. It took most of the reflection off of the surface, more of a satin natural aluminum. Looks like ass now but I wonder how it would look if I spent some time on it...

I'm still on the fence about how I want these to look. I'm still waiting on a couple of goodies, need to weld a few flanges on some of the pieces (BOV, wastegate, and blow through MAF) and decide whether vband is worth it or not so I have some time.

I'm feeling pretty strongly about either doing this satin natural aluminum thing with some elbow grease and clearcoat or going black wrinkle. If I do black wrinkle, when I build the short block I'll send the valve covers out to get wrinkled as well.

~Eric

 

[SS4Matt]

looks good eric, why are you using a wastegate with blower? or am i missing something here?

 

[347convert]

Huge intercoolers rock! Makes me with I just did a turbo Instead of doing a full engine swap.

 

[rockthemullet]

looks good eric, why are you using a wastegate with blower? or am i missing something here?

I'll copy over what I wrote on another forum

Seems logical....but, will it really compare to a positive displacement/roots type blower? Seems like it'll still be linear relationship from down low. :shrug: I'm not arguing the point...just trying to gain an understanding. It's a pretty damn neat set-up and if it yields those results, it's the best combo hands down. Low, consistent IAT's and a big curve starting down low. 2

It won't compare in the sense that the power won't come on IMMEDIATELY but it also won't be limited to the last 1k rpm or so. With the old setup, I saw 10.5psi at 6k rpm. With the new setup, I'm likely to see a linear boost curve up to around 4k where it would flatline at 10psi, giving me 3k rpm of full boost. Believe it or not, I would actually prefer this over a PD that sees 10psi at 2k rpm because traction is already an issue. The PD guys CONSTANTLY have to peddle their cars to keep the torque low enough for grip. I won't have that problem here.

Here is a couple more examples.

First, this shows a wastegated centri setup where they dynoed the car with the same pulley both runs. The difference being that in the second run, they limited the boost with the wastegate. As you can see, this is a 19psi pulley that was wastegated at 15psi. Instead of having a 15psi pulley and seeing 15psi at the top end, just like the 19psi on the 19psi pulley, running a 19psi pulley and limiting it to 15psi brings the boost on quicker than a normal 15psi pulley. Whew. Not sure if that makes sense. I'll try and draw a paint diagram after I post this.

Next, this shows a centri and a PD on the same graph. I'll include the caption of the photo below.

This Graph represents Grundman's Saleen versus a recently dyno'd Whipple-blown '03 Cobra. The boost curve (lower graph) is intense as the twin-screw blower is all over the centrifugal blower in the low-rpm range. But once 4,100 rpm hits, the centrifugal power curve overcomes it, despite the Saleen making nearly 7 psi less than the Cobra. According to Spetter, this Saleen would outrun most Cobras if they ran from a roll.

This shows that a centri is much more efficient and the same power can be achieved at lower boost levels.

Alright, to further expand on my first point, here ya go:

The red is a 10psi pulley
The blue is a 20psi pulley
The green is a wastegated 20psi pulley

See all of that area between the red line and the green line the ENTIRE rpm range? Thats all of the extra boost I'll see by running this setup. It strengthens the entire power band.

~Eric

 

[rockthemullet]

**UPDATE**

So, farting around I decided to clean up the engine a little and pull the valve covers to get powdercoated with the charge piping.

At this point, I tried to move or remove as much as possible to start tackling it...

At this point, I was getting frustrated about not getting any results...

Then I said fuck it...

Just got some parts back from getting powdercoated. I threw a few on just to take some pics...

Blower bracket and idler (that bolt for the idler OBVIOUSLY needs to go, lol)...

Still need pulleys, valve covers, coolant crossover, and a bunch more but here's a few things going on...

~Eric

 

[jtcstrat]

looks good

 

[Boomer!]

Damn that looks sweet !!!!!!!!!!!!!!!!!

 

[Birdie2000]

Looks awesome. Glad to see you decided to try out the wastegate on your setup. I'm very curious to see how it works out for you.

 

[rockthemullet]

MOAR

I got picture happy today...

The long tube going to the throttle body needs to get recoated so I didn't bother cleaning it off too much for the pics. The flange you see to the front of the strut tower is for my PMAS HPX slot style mass air meter. I had some fitment issues so I'll have to install that after I tweak some things and get the tube back from powdercoating.

For now, I'm really just waiting on the other valve cover and I have to buy a manual rack and a new bumpsteer kit since my current one won't be compatible.

Enjoi.

~Eric

 

[rockthemullet]

More updates. Got some just random bs done.

Interestingly enough, what you see is nearly all of what is going back in the engine bay. I still have to install the brake master and the driver side valve cover but as far as everything else goes, its all there. I need a tbolt clamp here and a wiring hookup for the fans there but its coming down to the end now.

Manual rack is coming tomorrow and the billet tie rod ends should be here beginning of next week. I still need to order the blower pulley and a belt. I'm sure I'm forgetting a few things.

~Eric

 

[jtproudmarinedad]

Look's good!! Nice Work

 

[orangejuiced86]

Looks good!!

 

[rockthemullet]

Yea, I'm getting there. I was thinking about having the intake manifold powdercoated but I'm not sure I want to deal with pulling that right now. I also want to redo the coolant crossover pipe and have only one outlet going to the top of the radiator. I feel the other hose doesn't serve much of a purpose and generally looks like ass. I could then run a one-in/one-out inline thermostat and it would really clean that area up.

~Eric

 

[82hatch]

Looks great!

 

[chacho44]

I like, i like