Looks good on the skunk manifold. Lots of little tweaks to get it to work, but I'm still very interested in the results it provides. Wish I had grabbed one off the trader initially when people were selling them unused for dirt cheap after hearing they don't fit.

Runners do look about 1.5-2" shorter then optimal for a 8000 RPM HP peak but going that long would mean no ABS. Did you by chance measure runner lengths?

 

I did not measure the runners, but they are indeed shorter. I would also say they have a more distinct taper as compared to stock.

The manifold does need some minor tweaks as you have stated, which consist of a spacer should you run the stock TB, minor porting of the runners, tap for ground wire, and securing the freeze plug if you so choose.

I do have the car running and we are making sure the fuel trims are good. I am also seeing some phantom knock so we are trying to sort that out. Some initial 3rd abbreviated pulls show the car running lean so that is a good sign.

I will update as we make progress on the tune.

 

You haven't won the bet just yet, but it was a pretty darn good guess. I had to spend a few days resolving an issue, but the car is now running strong so I spent time tuning today.

The timing curve is more conservative than what was being run before and I have maxed out the unmodified Walbro fuel pump, which is obvious by the AFR's leaning out on top.

So the before and after below includes the following changes:
- Skunk 2 Intake
- GSC S2's and GSC springs
- Curt Brown headwork
- More conservative timing curve

What is amazing is the car lost nothing down low and makes 6psi more boost at 4K rpm and more power/torque across the board. Once I install the new pump I can dial in the AFR's and then start adding timing so I still think I can make 509hp@wheels. I am also still on the stock TB so after the pump that will be my next mod. Lastly, all results are on 93 octane.

 

Sounds like it's heading in the right direction!

 

I am still amazed how much power/torque was gained at low rpm where I would have thought I would take a minor hit. The information for both the Skunk 2 and GSC S2's showed some minor loss at low rpm, but I gained. Even with most port jobs you typically lose port velocity, but the graphs say otherwise.

Makes me glad that I hit the exhaust valves because it gave me a good excuse to have you rework my head.

 

UPDATE:
I installed my new Walbro 400 yesterday as the unmodified Walbro 255 was dropping fuel pressure under boost resulting in lean AFRs. I will post pics of the install later, but below is a before/after with no other change except the pump. I had to start the run at a higher rpm as my soon to be dead stock clutch doesn't like the power.

It is important to note the Walbro 255 was spiking ~80psi, but would only hold 60psi. The Walbro 400 spikes to the same ~80psi, but drops and holds ~70psi. I suspect the Walbro 400 has a 70psi bypass, but need to verify with Walbro. Clearly it supports the power.

 

So the pump install was straight forward. The length of the pumps is almost identical, but the Walbro 255 is ~0.055" longer. Sorry for the bad pics as I didn't realize the camera was on manual focus.


I looked at modifying to retain the bottom clip, but when I inserted the pump it literally bowed out the clips. For me it would be silly to cut up the clip so I opted to retain with a stainless hose clamp.


I also used a stainless wire tie so the clamp would not loosen. When I tightened the clamp I momentarily hot wired it to the battery to make sure the pump didn't change pitch, which would indicate it being over tightened.


I then ran an 8g wire from the battery to one of the bolts on the top of the tank. I then spliced in a 12g ground from the pump ground to the 8g ground.

 

Congrats! BTW, great results on 93 octane pump gas!

 

I just ordered the same intake manifold. I appreciate your logging of install.

 

Almost bought the Skunk2 IM quite a few months back and then found a Wilson v2.3. Def wouldve bought the Skunk2 had it not required so much more 're-working'.

 

Apearantly it's minor tweaks though. Ive yet to pick a throttle body. I may go with the full blown since its competitively priced.

Have you any relative manifold comparisons?

 

Yeah its just some porting here and there and a few other things. Not sure if the bolded part was aimed at me, but not really sure exactly what type of comparisons you'd be looking for...?

 

No that was asking to compare 240z's stock im vs the s2 unit (didnt mean to confuse ). Some porting, we will see, Im sure even the hobbyist could achieve the cleaning this needs with a dremel(i will probably eat my words there!!!!). I have 3-4 months or more before my evo will see life again.

 

Glad to see and would be interested in before/after with just the manifold swap. I had hoped to do the same, but since I pulled the head I just did all the mods at once. BTW, what TB will you be running? The reason I ask is that I made some additional TB plates if you need one.

 

If I understand the question, the results I provided are before/after of not just the intake swap, but also GSC S2's and Curt Brown porting/bowl work.