GT-ER

Why care if it puts down 400whp or not...you have a VERY quick car. If you wanted a quicker sedan you'd get an E55 but then it wouldn't be such a sharp handler. You gain in one area and give in another. Enjoy your car.

91RS

Because I was expecting to have 400whp with just the SC and 450whp after the exhaust. If I would have known, I wouldn't have spent the money and just drove the car the way it was for a while and then probably upgraded to something else. If you look back earlier in this thread just about everyone else seemed to think I should have had 400whp before the exhaust, too. dre5373's car put down 377whp with just the Kleemann headers and custom exhaust (also on a Dynojet)!

GTibunny8v

Something doesn't sound right. I don't understand how you ran a 109ish trap speed with a
blower. I was running that stock with 60F temps and I ran 110.5 with tune and secondary cats removed and true duals in 90F temps. Have you tried running in dyno mode?

GT-ER

Yeah but you really need to wonder how one gets 377whp out of bolt ons. My friends C55 with kleemann headers, exhaust, renntech intake and ecu tune managed only 312whp. Plus, 377whp on a C55 would put it in the mid 12's on street tires. It just doesn't add up.

91RS

The last two times I went I ran in dyno mode so I could do a proper burn out. Last time I had 12.8 @ 108 all night (8 runs). My best run I managed on my 255/35/18 street tires was a 12.7 @ 110. Once I bought the Mickey Thompsons 245/40/18, my best was 12.7 @ 109 (but I only did that twice on the first time out with them, typically was 12.8 @ 108). That was all before the headers and custom exhaust, so it still had the stock primary cats in place.

91RS

Was his car just Kleemann headers or was the rest of the exhaust completely redone as well? My exhaust was made based on Dre's car (it was what I would have done anyway, but he just had it first).

dre5373

My best time was 12.796 at 109.89 on street tires. Just got my Hoosier DR's and light 16" wheels today. I'd like to do a run on them before the cams, intake and crank pulley go on, but MIR is on the 17th.

Can't really say why the dyno was so high, I am running catless, and the way the x-pipe was fabbed looks like it would do a much better job at promoting scavenging than any of the prefabbed stuff I've seen. The custom tune helped a good bit too.

GT-ER

Those traps are consistent with a 320-340whp C55. I ran 12.6@111mph on a 3500lb Pontiac Grand Prix with 340whp and horrible gearing ( the C55 gearing is far more aggressive ).

I hope I'm not coming off as a hater, on the contrary, I just don't find 91RS' C55 slow.

GT-ER

Dual 2.25" mandrel bent all the way back.

dre5373

No worries, didn't interpret it that way at all

Nachtsturm

Have you gotten a tune yet?

In a heavier CLK55, I just ran a best of 12.98 on all seasons, full weight. My traps were from 105-108.

Funny thing is my traps are down from when I just had only headers. Traps were 108-109.

I think I need a custom tune for this airbox.

betrezra

Nach - you might want to see what your fuel trims are doing via STAR DAS or OBDII scanner. I've heard some people reset adaptations for improvements on the dyno..... could help at the track as well.

91RS

I'm not really saying it's slow. I'm saying for my expectations and the money I spent, I'm not happy with the result. And there's not really anything I can do about it unless I go dumping a ton more money into it.

91RS

It has the Kleemann tune now that I've done the exhaust and removed the factory primary cats.

GT-ER

If only you had the autorotor you'd have a better shot of making big power but the mp112 isn't exactly great. :-(

91RS

Well, of course you were right. Best run today was 375hp. But I'm just not sure I believe it, it doesn't make sense to me. How can a 10hp increase get 0.5 seconds in the 1/4? Kleemann told me the headers should be good for 50hp. I think it does have at least a little more in it anyway because it gets very rich by the top of the RPM range. The first run it was crazy rich and I backed off the Kleemann fuel pressure regulator about half a turn and after the next run another half turn. It lost a little power on the second run but gained a little back on the third run. Might have possibly been heat soaked by then. The fan probably wasn't providing the same amount of air flow as driving down the road at 100+. By red line it was going 155mph. All runs were in 4th gear. The A/F ratio looked better on the stock tune! Smoother if nothing else. Probably could use some tuning changes. I also completely forgot about checking the boost. I have videos, I just have to upload them.

91RS

91RS

Cobalt as well for anyone who may be interested.

betrezra

Afr could be increased up top. 10.8-11.2 would be better for power.

Low 12's is great!

Keep in mind dyno's run at kleemann co are corrected to sealevel........ So grain of salt.

Your car is great IMHO.

91RS

My car has never been to Kleemann so I never had a dyno from them. I also never had a before dyno because I couldn't get the timing right. My before exhaust dyno was done on the same dyno with the same operator as todays, just almost a year ago.

I'm going to call Kleemann and see what Cory says about the A/F ratio and the tune. I also still have a Eurocharged tune I've paid for from when I was N/A, so maybe they can do something with it. Although, I don't think they have a way to do any data logs to make sure everything is good. Plus, at this time I don't have a way to install my A/F gauge because the damn plug seized up in the damn bung... I just removed one of the rear O2 sensors for the dyno.

betrezra

I'm pretty sure your car would make 400rwhp corrected in Colorado.

I have seen dyno shops simply stick a probe in the tail pipe.

Gl

91RS

I have too, but you get a more accurate reading with the sensor before the cats. I had the extra bung installed because I wanted to install my A/F gauge permanently. It'll fit perfect where with the ash tray insert removed and I could still close the door and not see it when I don't want to. Now for my to do that I'll probably end up buying another left down pipe from Kleemann and have it welded in with two new bungs. I paid all that money for the exhaust, I wouldn't want it screwed up looking with 3 bungs in one spot. I would like to get the A/F ratio closer to 12.2:1 if that is possible. I know Cory told me once that there were some tuning issues which is why they don't use bigger injectors for the fuel system.

GT-ER

12.2 on 11.1:1 compression and pump gas is a no-no dude...stick with low 11's to be ultra safe. The power gains will be minimal going from low 11's to low 12's and the safety net will pretty much disappear. High compression, inefficient supercharger and pump gas are a troubling combination. This is why E55's run 9:1 compression.

With that said, you are looking at peak numbers but perhaps the area under the curve got much better which could explain the great gains in the 1/4 mile.

Remember, I have a blown C55 engine in my garage right now....please don't join me.

91RS

I'm not trying to blow it up, I'd never heard anyone say that wasn't safe on this engine. I've always heard everywhere that 12.2 was ideal for under boost and 14.7 when cruising. Even in betrezra's thread I'm pretty sure I'd seen that talked about, although I think he said his car was running around 11.2. My main thing was just how wavy the graph is, it was smoother on the stock tune. Do you think it's safe like it is or should I turn the fuel pressure regulator back to where it was? It looks like it was staying fine at 11 between 5k and 6k. I'm just OCD and want it "right." Whatever right may be. I spent so much time during the install to make it look "right." I've had quite a few people tell me it looks completely stock.

I just wish I had known all this information at the beginning. I think it was betrezra that said somewhere on here that people don't seem to want to share much information on how to make these cars fast. I might have still done it, but then I know at least I wouldn't have been irritated about the results.

GT-ER

I think 12.2 is way too lean for pump gas on such high compression. The car will never run perfectly as it should unless the regulator setup is removed, larger injectors are installed and the car is tuned for it. Keeping the regulator setup will be good enough though which is fine, just lower the pressure slightly and get your A/F ratio in the mid to high 11s. The wavyness of the graph can mostly be due to low timing, add race gas a raise timing and the wavyness should mostly be gone.

Also, 4th gear is a dyno with little airflow is a problem. You'll heat soak half way through the run. Dyno in 3rd, I ALWAYS dyno in 3rd.