Gone too far...Can't tune on the street
 

The good news is that we found the end of the fuel system running e85. For sure the fuel rail pressure and the hpfp were humming along but when I bumped to 14psi with e70 (pump e85), the injectors hit their limit. In a run yesterday we saw 7.5ms on the injectors.

That brings me to the real point of this post. Trying to run 14psi on my street tires with cooling weather is not doable. In fact, it's downright scary!

In the past, I would get into 4th gear on the on-ramp slow down until I hit the straight away and then hammer it. It would let me log a good run to 6500RPM's. It was a little tricky before, but upping to 14psi...forget it. I was in 4th gear and anything below say 80mph would just spin the tires...not even a hint like it was going to catch hold. It was ridiculous.

I was on the same stretch of highway that I used for all of my runs, so while it might not have been the best, it has worked.

Bottom line is, I am done for the year. I am going to switch the pulley back to the 85mm pulley (8psi) which will be the 705whp/830hp setup. Once I get my new tires and the weather warms up, I will resume testing to figure out which boost level is best for the street. Once I can get to the track, we will resume the testing with the 14-15psi pulley and race fuel.

Recap:
85mm - 8psi - 700whp
80mm - 10psi - 730whp
75mm - 12psi - 760whp
70mm - ?? - couldn't finish testing

I think we could have played around with the 75mm pulley and gotten a higher number if we wanted to play with the dyno. We didn't force the converter to lock early and on the dyno we were seeing 1 degree of timing less than on the street. I am really confident we could have gotten 780-800whp at 12psi if we just wanted to get the dyno number. However it was driving so great and on the street runs the numbers look so good that we decided not to mess with it until we can get to the track.

Most likely, once I get better tires, I will return to the 12psi setup running pump e85. I think that setup might be good enough to run exactly the same on the street or dip into the 9's on the strip.

If I fall short of the 9's with my street setup, I will have one more lever to get over the hump and with 14-15psi, we will definitely get there.

I will be moving to the cosmetic section for the winter. :sm0:

Get some Nitto 555r 305/35/20 and it will be a night and day difference. I just put a set on mine and went from spinning on a 40 roll to dead hooking from a dig. I pulled a 3.5 0-60 yesterday with no effort at all and still 28 psi in the tires on 50 degree roads. They also ride and drive really nice compared to all the other drag radials.

Obviously 2 different levels of power here but you get the idea. I wouldn't be surprised if you could effectively use 2nd gear with your power.

That's a good problem to have. LOL.

Yep. I will get MT's. The issue is that I am running 285/30's on front. Because of the size difference, I have to get all 4 tires. I also have to move the wiring harness. So, I will get them, but there is no reason to get new tires now when I wont really be driving too much for the next 3-4 months.

I have a new hood and chin splitter on the way, so I have other projects for the winter.

Just gonna be upfront and say the Mickey's suck. They look great but they are heavier, cause the ass end to wag, and wear fast. Not something I would want on my street wheels.

What kind of mileage would you say is achievable with the 555r's? Let assume just the occasional pull here and there?

I have Nitto 05's on mine. They are the non "r" and while they were decent when I first got them they will go up in smoke in a 2nd gear roll. I was considering the 555r's next as I hear good things about them. Just wondering if I don't beat on them daily if they'll last more than 3k miles.

Thanks

Edit: What size front tire is need to run with these 305/35/20s? I know I had some issues before where you can't exceed a wheel diameter difference between the front and rear beyond a certain degree before it trips the Anti-lock brake system or something.

Agreed on the street. But the 17 and 20" Nitto 555Rs are too tall without a taller front tire. Tall enough perhaps to set off the Stability control on my ZL1.

Nittos don't hook anywhere near as good as a Mickey drag radial. I ran the ET Street S/S on my 1000 rwhp 4th gen and they did great on the street. I wouldn't even look into running a Nitto.

I am going with 275/35/20's on front. I currently have 285/30's. I was told that the difference in diameter was going to be too much. The cheapest way to go would be the Toyo R888R's...they have the size that would work with my fronts 285/30's, but based on feedback from the forum, they are too loud and simply don't come close to allowing traction at strip. They might be a good choice for street, however. . .will let others chime in.

You’ve got a great all around setup and I’m impressed with what an LT4 system can do on E85 with a cam and with no methanol. It pretty much covers the limits with what you would want on the street with a hard hitting, high torque, 2300 Magnacharger. I think a race gas tune would easily cover what you would want with a small pulley for the track. It would also easily cover what you would comfortably push the rest of the drivetrain. I’m anxious to hear your driving impressions with this setup given a little time and maybe some drag radials

You may already be aware of this site but if not.

https://tiresize.com/comparison/

Will give you all the details and even show the difference visually.

FWIW: I have a 275/35 Front and a 305/30 rear now. Unfortunately Nitto 555r's don't come in a 30 . :rolleyes:

No they aren't. I am running stock 245/40/20 up front with 305/35/20 555r in the rear with no issues.

I have had both, the Nittos are better on the street all around. The Mickey will hook better at the track.
Some have got 10k miles out of them. I would say double the life of a Mickey easy...plus they ride better, handle better, and will do OK in the rain. I have had Mickey's and Nittos on different cars. My brother also has the Mickey on his Scat Pack and doesn't like them. The ass end wags at high speed. My 4th gen did the same thing until I switched to a Nitto.

You don't need to change fronts. They Nittos are a little shorter then the Mickey also so they don't mess with stabilitrack. Stock front is 27.7, the 555r is 28.58, and the Mickey is 28.7. Rule of thumb is less then a inch difference front to back and you are good.

Good vid here. ToyoR888r prolly the best street tire option. If you don't mind spending the money.

https://youtu.be/piX4-AzxB2Q

I can also confirm...I was running stock front 245/40/20 and Nitto 555R 275/40/20 in the rear. No issues at all. That's about a 1" difference. I can also confirm no issues with stock front 245/40/20 and Nitto 555R 305/35/18 in the rear...that's over a 1" difference the other way.