Have kept the 9 plugs because have seen a fair amount of people with 500whp+ using them, i did order 10 heat range but didnt get here on time.

My knock readings are low, turning around i may get as high as 80. I seem to have a lot of drivetrain noise, while on boost knock stays below 25-30.

 

Any more input guys? Can't sleep at night thinking about this issue

 

It looks like your power rises slowly, alot slower than my dyno sheets, so maybe that's why you are not spinning the tires in 2nd gear. What is your 1/8 mile trap speeds?

What kind of boost controller do you have? Does your power come back on slowly in between shifts? How much drag racing experience do you have? There are soo many factors to why you aren't getting good results yet at the track. Look at one of my dyno sheets here http://farm7.static.flickr.com/6096/...45ba1827_b.jpg

 

I wouldn't overlook the fact that you added water injection post tune.

My motor was making 400rwhp before my 2nd tune, I added water injection the week before the next tune. Car was breaking up like crazy at high rpms on the dyno. barely made 260rwhp. We had to pull out a TON of fuel...broke up so bad we thought there was a major problem. It was simply the mixture of water/meth added to the intake charge causing the AFR to drop and blowing out the spark. Finally tuned it out to 440rwhp.

I would re-dyno the car w/ the water.

 

Try a different dyno.

thewird

 

@Tom

Not much into drag racing, just went to the track to test my theory that the car did not feel like a 475 car, and trap speed is a good way to confirm this, thats the only reason i went to the track.

Boost controller is a greddy spec b 1.

 

Last time I went to the track I lost about 2 mph off my trap speed when I turned on my water injection. I was spraying over 600ccs of 50/50 with a 350 rwhp setup so needless to say I wasn't turned for it. I have a hard time believing you'd loose 10 mph from WI alone. That is strange, I'd say the dyno was wrong unfortunately?

 

Clutch slippage?

 

I am thinking that maybe the clutch isnt transfering the power the way it should, i should start looking into a twin disc.

 

Do you feel any hesitation at the top of the power band?

 

Yeah, kinda like he wants to slip.

 

just for reference:
i ran 115mph in the 1/4 with ~310-320whp on the stock twins, stock block, stock intercooler, open downpipe, and powerFC, ~14psi. 12.09@115, and the 1/8th ET was 7.78@92.

i would guess yours would trap 125.

 

Do a boost leak pressure test with an air compressor, just so you can at least cross that off the list. You can make your own out of hardware store parts, or purchase one here (Universal tester near bottom) Boostpro.net : Products - Boost Leak Testers . I've seen boost leaks at the strip cause major loss of mph. After that, see if shifting at 8500 helps.

 

Raymond, wouldnt a boost leak show on the dyno graph? I was loggin boost as well and it was a pretty flat curve.

 

A boost leak might show up, but something could have leaked after leaving the dyno as well. I've seen mph drop after every pass from a leak getting worse.

it's a cheap thing to check.

 

Boost leaks don't always show in the boost also.

thewird

 

Running those plugs at that boost/power level you're asking for trouble.

Do you have any pics of your portwork? As I recall you had a local guy do they for you.

 

You're water injection is kicking in at 8psi ?

I would change the heat range of your spark plugs to 10's on all 4 as well.

That water injection will kill some power, I tried it on the dyno and would lose 30-40whp. Granted I think in my case my ignition system wasn't keeping up.

With water injection kicking on that early, I wouldn't say it's helping much.

 

Gear ratios
1st 3.483
2nd 2.015
3rd 1.391
4th 1.00

1st rev 7,900rpm 2nd drops 4,600rpm
2nd rev 7,900rpm 3rd drops 5,400rpm
3rd rev 7,900rpm 4th drops 5,700rpm

At 4,600rpm your graph shows 200hp and 5,400rpm less than 300hp. You need to rev it higher in order to use your actual powerband.

 

+1

As I already said, powerband is poor, don't take it as offense, its rather consequence of typical streetported engine and flat boost curve. There are many single turbo RX-7's around 500 whp level, but not many perform as car under 3000 pounds should perform with such power.

Your true powerband - place where you are producing most average power, starts at 7k rpms and basically you want be above that all the time. We know its not possible without close ratio box.

Run more boost in midgange, bring your powerband to "normal" rpms and then car will perform as "peak" power indicates

 

Kind of seems like with that theory one would be quicker running stock ports with extra boost to make up for smaller ports? It would have a larger power band correct?

 

Any dyno graph of 67mm non ball bearing turbo 20psi to compare powerband ? And horsepower level at 4,000, 4,500, 5,000, 5,500, 6,000rpm

 

Well you have to remember that the gearing is a factor here. With OP's powerband, you certainly don't want to fall below 5000rpm. So you have to shift at 8000 at least.

Now look at all the new turbo direct injected piston engines. They are relatively low revving, maxing out around 6000-6500rpm and falling on their face after 5000. However they make full torque under 2000rpm. Typically it's a relatively low lift & duration cam profile with a lot of scavenging (from variable valve timing) to spool the turbo. Then throw a ton of boost on top of that. It can take 25+ psi to hit peak torque that low on a turbo 4 cylinder.

In the same way, stock ports on a turbo rotary (n/a has aux port induction) are optimized for mid range and broader torque. When you have a ported engine with later intake closing timing and thus longer duration, you lose volumetric efficiency and mass flow through the engine. Then the bigger wheels of a single turbo have more inertia (especially journal bearing), so they take a while to spool up during transients.

 

Stock 9's was used just for tuning.

Rich i will try to upload a pic of the porting.