Yes. I am really intrigued by both the Needswings full custom manifolds and their tweaked stock manifolds. If they meaningfully reduced the boost pressure it would help the supercharger dramatically. The discharge air temp would be reduced as would the HP required to turn the supercharger. In fact, wouldn't the primary increase in HP to the wheels from the manifolds be from the reduced HP used to turn the blower? We have positive displacement superchargers, which means that they move a relatively fixed volume of air per rotation.

The manifolds are so expen$ive though... I am not convinced that intake manifolds would yield enough additional HP for the $$ to make me happy. Same story with exhaust headers (longtubes or shorties). Except for nitrous, I am not sure there are any more mods that would make good HP for the money. What's next? Convert to ethanol?

 

Don't bother with the headers. I'd assumed with one little exhaust valve and restrictive manifolds, headers would make huge power. They don't. 4 hp is what I got from top of the line long tube headers AND the install required lots of wizardry and improvisation. I'm sure the headers would be worth it if we could raise the redline to 6800 and up.

Les

 

Great job and nice write up. I am running a 181 and machined OEM supercharger pulley 70 mm with the modified manifolds, the SL55 pump with the adjustable fuel pressure regulator but I am just getting things together now and haven't data logged yet with everything in place. I have to find a good place to do this as I don't plan on going to the track and won't be putting on slicks or icing the engine, just as I drive it around. I do hope to be pretty quick. One thing I would be interested in knowing is if there is a difference between the EC tune and the INmotion tune. I do wish the 550 injectors were a little cheaper, if I need them as I suspect, I'll have to break my piggy bank.LOL

 

Have I done all the "easy" stuff? Am I missing something amazing, straightforward and obvious? (See sig)

 

Noted.

I am running a 26.0" tire at the drag strip (255/50/16), which I think is the diameter that is on the SRT6. On the street I am running a 25.0" tire currently (255/40/17), but I am going to switch back to the OEM 24.7" tires on the next set (245/40/17). The 255 street tires slightly rub in some conditons. There is about a 5% gearing variance in tires sizes right there. But switching to a 3.27 would be a 6.5% reduction in gearing. I just re-read Anthony's thread and I am really interested in 3.27 gears now...

 

I think you have.

 

I've got a 3.27 carrier in the garage (for cheap) if Les doesn't buy it. Gearing made a world of difference for 0-60 MPH runs at a minimum.

 

I want it. I'm waiting to hear from Rudy on the TCU. I like to figure my total cost before buying parts.

Les

 

Head check: Let's talk about supercharger pulley ratios. Below is the chart we are discussing.

blowerpulleyratios5-1-14_zps578b3c95.jpg

The 65mm and 178mm pulleys are approximately a 15% increase in supercharger speed. Many have run these all day long with no fuel mods - easy power.

The 185mm and 62mm (61.9) pulleys increase the supercharger speed 20% and are great. An upgraded fuel pump and logging or tuning with a wideband O2 are highly recommended.

tighed1, Grip Grip, and jefasold have all had success in the 24% overdrive area with their 192, 181/71, and 181/70 combinations. Intercooling mods, major fuel mods, and a good tune are absolutely necessary to push the supercharger this hard.

I am the nutjob in the group overdriving the supercharger 32% with a 178/65 combo. I commuted in the car today and the torque is just crazy. I had a lot of fun. That is a big gap between me and those guys though. There are not any available combinations inside that range. I wonder if I might be able to back off the supercharger overdrive somewhat and still make as much power. We know that 66mm is the absolute minumim that a stock pulley can be turned down to. I have half a mind to have one machined down to 67mm or 68mm to test this.

 

My data is 11.992 @ 117.40 with the 178 and Code3. 12.01 @ 116.89 with the 178. Not much considering the boost difference. (same tune)

Les

 

I am probably going to have a retune (INmotion) since I added the machined OEM pulley and adjustable fuel regulator. I would love to meet everybody and just have a BS session. I could talk for hours about the Crossfire.

 

That MPH tell us that your car makes damn good power and we should not put so much stock in dyno numbers

 

I'm not drawing conclusions as to what's possible running stacked. boostmonkey has the fuel system worked out and I don't. Keep tweaking boostmonkey, I'm anxious to see what we can learn.

Les

 

Awesome that you're pulling this with stock intakes!
That isentropic is amazing also!

Note - the stock intakes are providing a restriction, subsequently lowering the pressure of your SC intake manifold. Lower pressure means lower temps - maybe even 15F lower than ambient - at your inlet air flow rates on a stock intake/throttle/snout.
By removing this restriction, not only will you move more into a lean condition - more air (as you would be very aware), but your SC inlet temps will increase (~5+F) because your SC inlet pressures will move more back to atmospheric. Subsequently your SC outlet temps will increase - maybe twice that (your packing 2x as much air mass out) - so ~+10F.
But you seem to have enough thermal inventory in your ice tank/water setup to maybe cope with that (even when you're not running ice).

 

I can see where lower pressure will give lower temps but 15 lower than ambient? Where did that heat go? You'll have to prove to me that you will go below ambient temps from the intake to the manifolds just because there is lower pressure. I'm not a physicist, but I don't believe that. So explain this to us all.

 

they are cheap. i spent 1300$ for 6 1300 cc injector dynamics injectors. 400 for a set of 550 is peanuts!

 

Where are they $400? The lowest I've seen is over $500.

 

I'm running these:

Authentic Bosch EV14 52lb 550cc Injectors 48mm | eBay

In conjunction with these:



And I have MORE THAN ENOUGH fuel... LOL.

This gets you closer to $350 for everything...

 

So, based on my eurocharged 65mm pulley, you seem to be saying I could easily add a 178 crank pulley without other/further mods except perhaps a retune? If so, what whp/tq gains from a dynoed 340 would that offer given my sig if anyone wants to hazard an opinion? Thanks in advance. (Yes, I did see the table but was unsure of my interpretation)


@boostmonkey; The 65mm and 178mm pulleys are approximately a 15% increase in supercharger speed. Many have run these all day long with no fuel mods - easy power.

 

I stacked mine and on the first test pull I let off in second and removed the pulley. AFR's at WOT in the 14's. Got a retune and SL55 pierburg and tried again. It was still lean at the top of 3rd. but now around 13 AFR. I ran my car anyway at the track but had a tank full of 100 octane. I wouldn't even try stacking the pulleys without doing some supporting fuel mods beforehand. It's just too risky, and a risk several of us have taken and later concluded, "that was dumb!"

Les