Comp. Test + New DYNO Run ...wow!

[karmavore]

I’ve had some free time lately so I decided to get a compression test and head back to the dyno today to see what the cooler weather, and more importantly, my new exhaust would do for my numbers. Well, wow…. Just wow!




Here is my plot from this summer (same dyno, #3 Chip, K&N, Stock Cat & Exhaust)




Here is my plot from this Fall (same setup, different dyno)





Here is my plot from today (same dyno as run #1, STOCK S4 code, new 3” exhaust system turbo-back + 3” muffler and 3” cat)




Here is my new plot versus my old plot



Huge difference! ..and I was running the stock S4 code! Look how much smoother the curves are. I attribute most of the gains to the exhaust, but damn that #3 chip is so erratic.


So here come the questions/concerns:

1) My compression numbers:

1: 137
2: 135
3: 138
4: 138

A bit low, eh? What do you all think?

2) The operator and my very knowledgeable friend that was there thought I got a bit too lean in the upper RPMs. What do you think? I’m thinking rising rate FPR. Any other ideas? This would also help explain my knocking issue too. In fact, the guy was worried so he would only let me do two pulls.

Here’s my Freescan log of both runs: www.karmavore.net/jane/dyno.zip


Thanks for any help, fellas!

Luke.

[karmavore]

..also note that I only was only at .85 bar cos of the stock S4 code. The higest MAP I saw was only 2.09

Luke.

[GUY JOHNSON]

Your compression is seems low. I had lost compression in my # 4 and it was 120.

My understanding it should be about 150 160. Talk to your lotus tech and see what he recomends.




Guy

[NJGSX96]

Nice runs! I told you it was that chip. That looks more like what you should've been seeing. I think 2.09 is just about 1 bar though... 2.25 on the MAP is 1.25 bar I think. Boost is approximately MAP-1.0, rough estimate. Smooth code coupled with a freeflowing exhaust will get you everytime. I can see where you go lean and you can see the dip in the run at the same time. I would lean more towards maybe the injectors. if you can, throw a fuel pressure gauge on the car and see what that is all about but I think the injectors, which aren't good in the first place, could be the culprit.

Did you do the compression test like I told you? Did you use the kill switch for the fuel pump and let it die? Also, did you add a cap full of oil to each cylinder and repeat to see if it went up?

[karmavore]

Thanks guys!

re: compression. I didn't do it, the shop did. I may buy the tool and redo it myself or have it done someplace else for reference. Would I get those numbers if something was blown?

It should be 140-150, right?

Luke.

[NJGSX96]

If you don't use the pump kill switch, you will get false readings.

I wouldn't say anything is blown, but if those readings are right, could be worn rings. Those aren't so low I would worry. i think the servicable number where you are recommended to recodition whatever is worn is under 130.

[karmavore]

NJGSX96 said:

if you can, throw a fuel pressure gauge on the car and see what that is all about but I think the injectors, which aren't good in the first place, could be the culprit.

Hey man, what do you think about aftermarket injectors? WC sells RC units, and I'm sure they're great, but $720 for 6?? Seems a bit high.

Luke.

[njgsx96]

karmavore said:

Hey man, what do you think about aftermarket injectors? WC sells RC units, and I'm sure they're great, but $720 for 6?? Seems a bit high.

i am not sure if you need them without you doing further tests, but if you want new injectors, I would go with either five-0 motorsports or directly go to RC Engineering and get them. I agree that $720 is absolutely rediculous for a set of injectors. Five-0 is the place I would go and probably will if I ever need injectors. They guarantee only 1-2% flow diffence and will give you the data sheets to prove it, for piece of mind. RC does the same but are more pricey.

>> Edited by njgsx96 on Sunday 16th January 05:04