I went out this past Friday night to some race spots and ran a few cars:

1st run) 550 awhp Mitsubishi EVO on ethanol running GT35r (I thought he was talking up a story when he told me 550 awhp. I thought he was on a fully built motor running 9s with 700+ awhp) These cars run 140 trap speeds easy when they start putting down over 700 awhp.

VIDEO:

http://www.youtube.com/watch?v=5U_7lqecOZs

2nd run) 750 rwhp 240SX. Running a KA motor fully built (dynod 735 rwhp) but upped the boost so he is estimating 750 rwhp when we raced. Car weighs in at 2950 dry so this car moves. I have a video of the run but it wasnt that great so I didnt bother posting it. I had a passenger the 240sx did not so he had a weight advantage.

The owner of the 750 rwhp 240SX has a friend of his with a 2800 lb 240SX with a similar setup putting down 580 rwhp. His friends car ran a 137 trap at the track on an 80 degree afternoon months back. The 750 rwhp 240SX With 150 lbs more weight and 170 more HP pulls away from the 137 car pretty easily and believes he will trap in the low to mid 140s.....reliastic I guess, but who knows.

Anyhow, during the run against the 240, I was getting some sort of boost (maybe compressor surge) or fluttering in the middle of the race against the 240. In other words my car did not pull as hard as it should have. I did not experience the boost issue during the run with the EVO.

Nevertheless, I pulled ahead from 65-160 by 3 cars. If the boost held solid I believe I would have been maybe another car ahead. Also I had an extra passenger which accounts for approx. a car length as well.


Here are the mods on the 240SX KA Motor HTA3586 Turbo:

Engine Mods:

-brian crower cam stage 3
-brian crower valve springs
-Stock Valves
-Port & Polished Head ( Match ported to intake and exhaust manifold)
-Stock head gasket
-O-ring block
-ARP 11mm head studs
-ARP main studs
-crower rods
-weisco piston 9:1
-toga main & rod bearing
-ATI front pulley
Turbo Mods
-HTA3586R turbo
-Peak boost exhaust manifold
-Tial 44mm wastegate.
-Profec B boost controller
-3.5V-Band exhaust

Intake Mods
-Custom Intake Manifold (Thanks you very much my shop partner and friend Victor Hernandez for fabing a wonderful intake manifold. Without him this car would not be making the power it is today.)
-70mm N1 SR20DE throttle body
-Custom fuel rail
-Custom intercooler and intercooler pipping

ECU
-Engine Management System 4860 (Installed and Tuned By AndreEMS)
-M&W Pro-14 ignition box
-CDI 600cc bike coils

Fuel
-1600cc injectors
-twin intank walbro fuel pump
-nismo fuel pressure regulater ( Base pressure at 55psi)

Here is a link to his setup:
http://www.ka-t.org/forums/viewtopic...2bca4556306cbc


Soon to come: I will post a video of a run between a friends fully built cammed supercharged ZO6 putting down well over 800 rwhp maybe close to 900 (well know soon). He has a few things to clean up with the tuning before we run. He and I were playing around a bit and it looks like our cars will be a very good run. He is getting methanol installed this week and his tune should be wrapped up by the weekend. I'll post videos of that run soon once the Z is ready.

Also trying to arrange a run against a Heffner Gallardo Twin Turbo. If that happens I will post the videos as well.

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In the meantime, trying to pinpoint my boost fluttering issue. Anyone have any idea as to what it might be? I am hearing what sounds of what sounds like compressor surge where the "woooooooosh" sound of the turbo under acceleration sounds like its going up and down in waves as RPM climbs. Power also feels down when this is occuring. I lower the boost some and it goes away.
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Was going to try the following things:

1) Have been using pure MS109 till now. Was going to try throwing in 1 gallon of C12 in with 5 gallons of MS109. Was thinking we might be at the upper limits of MS109 at this power level. Ill run the car and see if the problem clears up. If so, retune the MS109 program down some to offset the issue.

2) We are way past the capability of the MAFs once we exceed 1.3-1.4 bar. Wanted to try disconnecting the MAFs eventhough Todd already disabled the diagnostics on them. Its possible the connected MAFs may be interfering with the way the car runs when the boost is cranked up passed their limits. Although the car may throw fits and trip ABS lights and so on, Ill give this a shot and see if it helps.

3) A few people say its compressor surge. Todd told me that from his experience, when 996 tts fitted with 3076s were on his dyno and were showing some compressor surge, it was happening at low engine revs (like 2500 rpms). Nothing above this on 3076 turbos in his experience. Also if compressor surge occured during his testing, he said that you would get a more dramatic negative reaction from the car than just audible waves in air and a slight feeling of power loss.

4) Todd was going to review throttle position from the Scan XL log files from my cars runs from a few weeks ago to review Throttle Position data to see if he can pinpoint any issues with throttle closing up.

5) Gain percentage is too high on the Greddy Profec boost controller causing the surge noise. I have it set to 14%. Too high??

Any other ideas on what it may be?

Keith

 

Welcome back man ...

 

Nice races.

 

Nice runs ! please video the next race in HD

 

Lowering the gain on the Profec boost controller solved the compressor surge problem.

I can now turn the boost up to higher levels without any issues.

Gain was set to 14%.
Lowered it down to 10%.

Problem solved. Cheap repair huh? LOL.

 

Nice runs.. If you just had the fuel system to support E85.. More power, less boost.. Cooler EGT's.. I havent used VP in 2 years.. 2.20/gal from the pump..