I've come to "my own conclusion" that stacked pulleys are not made for a 11 second street car. and i also believe that i am accurate in saying that 94% SRT6 owners are NOT dedicated to the drag strip but rather enjoy driving their SRT6 down the street but when approaching any Porsche or SRT8, say "yea im bout to spank that a**". Having said that, i find it VERY hard to believe that the select FEW that are running stacked pulleys (with stock injectors at that!!) dont even go above the posted speed limits, but just like being able to say that they are running stacked pulleys. Im willing to put all chips in saying that stacked pulleys are almost next to impossible to have (on our cars atleast) for a "street car". Its easy to build a drag car. The hardest thing to build is a street car. I believe that if those few that have stacked pulleys ran their car the way the mods were intended to be ran, they might encounter something catastrophic. Otherwise, whats the point?? De-mod and run the car with enjoyment!!!

 

While there is some validity to what you say, it is not entirely correct. I know of at least one other SRT6 set up like mine running 181 and 70 stacked set up, stock injectors, adj. regulator and SL55 pump plus DCAI, tune, modded manis, colder plugs, larger HE, plus some mods to the grills for added cooling; I only did ONE 1/4 to see what it would do, all other driving has been on the road. I don't drive like a granny, nor do I drive like a crazed lunatic, I don't see why the stacked set up can't be enjoyed on the road. For me, it was an engineering exercise, to see if I could still get as much as I could out of it, while still being pleasant to drive. I also devoted some time and effort to improve the braking and handling. I think that I have made a d__n good GT car.

 

I agree to an extent. I know I don't use what my car has to offer on the street. The closest I get is testing a fix for something. Usually a 5 to 60 blast when no one is around. Beast mode is for the road course which I hit frequently.

Stacked is great for the street IMO. The boost and torque are instant and when you get on it, it's usually for 100 yards. Short blasts are safer IMO. The high boost at low rpms makes it hard to drive smoothly though.

For me it's a game of where's your tuner. IF I HAD A TUNER I TRUSTED LOCALLY and my goal was the 1/4 and 1/2 miles I'd be stacked with nitrous. My new shop likes the Russian tuners …….. whoever they are. No trust!

Les

 

JR, just don't go overboard. Our SC is not designed to spin much over 15,000rpm. My 178/70 spins it at 15,750 right near redline. That is where I run a bit lean but I gave in and ordered a set of NEW BOSCH 550cc injectors and jerry will be doing the tune soon. I do not go to the track but I love the extra bottom and midrange power the pulleys I have give. The 70 is smaller than stock and the 178 crank pulley just enhances that 70 giving the motor more power in the range I want it, passing. Right now, staying in a good AFR range and that is partial throttle 100mph comes very quick. I should have the 550's and the tune in by mid October. I am hoping Rob has something on those headers by the end of october.
Let's face it. These cars do not have the potential to be especially quick. many new cars are much quicker off the showroom floor, however whether you have a Crossfire or an SLK you have a unique car. For me if I get into the 11's I will be happy as that is about all they will do. Remember the 178/70 is about the same as a 62mm SC pulley and Rob said that guys with the 62 pulley probably run lean or they don't have a wideband so they don't know. Running a 65mm SC pulley with whatever crank pulley that is larger than stock requires a lot of mods and patience.
If I can get the n550's to give me an AFR of 11.5-11.9:1 I will be pleased and then concentrate on the exhaust. maybe the headers will allow a few to get to the 11.5et which is over 120mph in the 1/4 mile. My track days ended back when big block muscle cars were sold as used cars that got terrible mileage when we had the oil embargo. Could have bought a '67 Dodge R/T with a 426 HEMI for $1300. I got my first muscle car, a '66 buick gran Sport for $450. from the original owner. back to the future. We are limited by the SC. If these cars had a turbo the power would be limited only by the short block's strength.
Stay with the 178 crank and the stock SC pulley or go for that extra part throttle power that I enjoy, choice is yours. I know you have been wrestling with this for some time, make a decision and stick with it. For me it is to get the 178/70 to run at it's full potential. Mark

 

I would love to hear insight from someone who is running 65 stacked.

 

If bottom end power is the key ...and lets face it...its the most used....get the EC manual TCU and have them set it and your ECU to a 5500rpm redline...that would solve your lean issues and possibly give a better pull all round.

 

I have the 550cc injectors on the way and short shifting would slow the car tremendously. The revs between shifts would drop too low. A little extra fuel will fix the issue and along with the E/C tune I expect to be quicker than ever, perseverance.

By the way I spend as much time at redline as I do at lower rpm's, just not at WOT

 

Another thought on this. Today, I cracked it WOT at 60 mph to 80 mph and with my brother using his stopwatch it took about 2.3 secs. That is quick and right about where I would use it most, passing etc. Understand, this certainly isn't an official time but to the point, it's where I want to have all the power I've got. I fabricated my exhaust for midrange power and torque as opposed to top end, it's more usable. That doesn't mean I have no top end, just that the torque peak comes a bit earlier. I don't think the car is at all hard to be smooth with, drives like a dream and then too, I don't have a throttle booster. I hope we all end up with exactly what we want.

 

I got the 550's and the tune from Jerry yesterday. Now waiting for the intake gaskets and somebody to do the labor.

 

Yes - I agree with the stacked community...all that torque at 2000rpm sounds so much more effortless off the line than the 2L AMG A45's that more recently have been trying to put it on.
Mind you there's quite a few hot rexxies around my town and I'm a little more cautious with those guys....Not many vettes 'round here.
Who'd a think I'm 50+...


PS: As per my Sign...I havent as yet gone with a 178 crank....but I'm working up to it....one day (+ the KC)
I plan on having this car for at least another 5-10 years...they only sold 28 of them here in the entire country (unconfirmed) ...so they arent depreciating too much in value...yet.

 

Jim, what did you do that you believe gave mid-range power? I feel as you do that having power where I am most likely to use it is where I concentrate my efforts. Around here 80 is normal on the interstate though I am trying to slow it down, Romans chapter 13. I know when the injectors and tune are in place the car should continue to pull as now I need to let off as the engine approaches 5500rpm. I can feel the nose dive down as it is up under power. These V6 motors have unbalanced exhaust pulses and need an x-pipe of sorts as close to the engine as possible, after that is personal preference. Curious as to what you did. mark

 

Sweet2002 - I hope you are reading all the past threads and knowledge on the effect of higher boost levels and in particular the NW intake manis....thats where you get most increases in torque - across the board - the intake manis specifically add better bottom end response (I guess - possibly becasue they arent tapered like the OEM's)....but I'm not sure the NW manis will fit an SLK32 with possibly less room under the hood...(note: I damaged my stock air filter after a broken angine mount - so she's close already)....

 

I did not use an X pipe but instead put a Y as close as I could and went directly into a single 3 inch pipe all the way back to the stock muffler, deleting the back 2 CATS and the resonator in the process. There is a small inline resonator immediately after the Y. It has very little restriction if any.

 

note - sweet2002 has an SLK32 ...not a Xfire....

 

Yep. Read so much it gets confusing after a while. I have not seen the intake manifolds give the power claimed yet. Rob said the tweaked intakes would give 25hp, maybe he was talking about the big ones, but I think the smaller stock tweaked and I have not seen anyone get 10whp from them. I am very happy with the torque my motor puts out now and it is just that little bit up above. I would be surprised if I was not running lean with just the 65mm SC pulley. I only added 6.6% more boost with the stacked pulleys. hopefully Jerry was right about my need for larger injectors.

 

My SC pulley has rubbed a hole in the pad on the underside of the hood. First the fuel issue and then exhaust work. Then...........

 

The taper is for a reason. The stock intakes have to make torque and also make top end power, a blend of both. maybe the $1500. intakes make some power but I have not seen anyone make anything over 10whp with the tweaked intakes and ported "Y" which seems odd as the Y and the inlets to the main plenum of the intakes are modified heavily but for some reason the return is not there. I'm doing exhaust in hopes Rob's headers make 15whp minimum. I figure if making 42% more boost should make a bit more spent gasses to get rid of making exhaust work more likely to have a good return the more boost that is run within the limits of the SC.

 

You mean the hood lining?...
Is it hanging down?
If you'r not afraid of making "non stock" then some remove this hood lining to help with the heat issue.
I don thave a problem with the rubbing apart from my SL55 air boxes rubbing...I've removed them for now to limit the damage to them and the lining. I need to mount them better and as low as possible.


Also as I mentioned in a previous post - once you break a LHS engine mount - it'll wear a hole if you dont pick it up pronto. Take note NOW of the play in the stick shift and when your engine mount goes - you'll notice this become much larger.


With your mods - and frequent WOT - you will do an engine mount. Find some cheap spares now.

 

Thanks for that advice. I was told without the lining on the underside of the hood it would of course be noisier and the extra heat could damage the hood's paint.

 

Jim, I did more research and the V6 motors go SLOWER with true duals or something similar. Your "Y" is what was recommended so I went with a TRU X-pipe magnaflow, "Y" pipe into a 3" single pipe leading to a 3" in/out Borla muffler out back.
Stacking a 65 SC pulley with a 178-185 crank pulley takes the SC out of it's efficient range so why do that or even try? Check out these SC's we have and you will find that 15,000rpm is the upper limit for it's efficient range. My 178/70 stack spins it at 15,750rpm ballpark. A 181/65 spins the SC at 17,265, a good 16% over where the SC was designed to make the best power. It may make good power at that level for a while but eventually will ruin the SC. A 185/65 spins at 17,646rpm's. Awesome torque down low but dangerous at redline or near, 5500rpm places the revs of the SC at 15,650.
I love the low end torque and as Jim states passing is within the regular driving characteristics of most of us and that is where I enjoy my car the most, on the interstate!
I also agree with you JR, drive the car where you enjoy it the most. Few of us go to the track every Sunday. Build it for the street and drive carefully on the street!