Hey guys,

Yesterday i went to the drag strip just for the fun of its and to see how my newly built engine felt. We tuned it two weeks ago to 475whp on gas and after tune i connected the WI as a safety measure.

Simply put the car is NOT putting the miles a 450-475whp FD should put. It only did 115MPH so i think i am off by about 10-12MPH.

My mods list so if anyone ask, pretty basic stuff.

13B-REW Med/Large Street
Precision 67/66 1.0 A/R Divided JB
Precision 46mm wastegate
3" Turbo-back exhaust.
550cc/2200 Injectors
HKS Twin Power with stock coils and 9 Stock plugs
FMIC
Coolingmist Stage 1 injection 100% distilled water.
Power FC
4.44 rear diff ratio
Nitto NT05 265/35/18.

My goodfriend and mentor Lucho (RX7DTS) after this yesterday we started looking for possible solutions, he is betting on the dynograph, he says i am not revvin high enough hence why i am losing miles, here is the dyno graph. Nevermind the AFR that was an error, actual AFR and final is 11.3-11.4.



How high you streetported guys reving?

 

dyno seems somewhat lean up top. but 475whp you should be doing 125-128mph in the trap speeds. i would look into your coils and plug/plug wires. i had one pop off on me one time and lost 70whp.

 

Like i said, final AFR was 11.3-11.4, just didnt took pic of that graph. Wouldnt a lose plug wire make the car feel sluggish and not idle/drive correctly? Car feels perfectly fine. SMG, how high are you revving?

 

We run the revs up to 8.5k.
Yes, at 450-475 you should be around 122-126 mph or more.
Many other factors play into this. What was your 60ft. time ??
Are the tires just spinning, or are you getting traction ?? Air pressure in the tires ??
What was the ET ??
You added WI after you dyno'ed, how much water ?? Maybe too much spray ??

 

WI was installed but didnt use during tuning, spraying 550cc of water, that could only take 15-20whp out of it. Still not mph for a 450whp FD.

Best ET was 12.7 @115 with 2.18 60'. Could have done a 12.5 but almost miss hifted 4th and lost a lil time. Tire pressure was 18. Street tires or Drag tires, MPH should only be off by 2-3 MPH, not 10-12 like i am.

 

At what point (psi) does the WI kick in ??

 

8psi.

 

I turned my boost down to 15 (453 rwhp), street tires set at 20, WI (50/50) at 6, ran 11.903 @ 122 mph.
I would think you would be close to these numbers.

 

Exactly, hence why i am looking where are the 10 mph im missing

 

no you will not notice it at all if its a trailing coil that comes off. and it does account for a good amount of power. mine was off i felt no break up idle change or anything just was way down on power. on 407whp i did 11.7 at 123mph so you should be up higher for sure. that was with a 1.8x 60'.

what boost level did you make you power at? 550cc of just water does not seem like it would kill your spark but you never know. what rpm were you shifting at? i usually shift at 8-8200 rpm

 

Power was made at 18psi off boost, it spikes to 20 then backs down.

Im shifting at 8k rpm, but i dont know, im looking at the dyno graph and at 5,000rpm im not even on 300whp, seems the powerband gets good at 6000 which is why im thinking maybe i should up the revs to 8.5k?

 

thats good power for that boost level. on my car on pump gas/meth i make 470whp at 22psi but i trap 130-131mph so i dont know if its just a difference in dyno readings. you can try and shift higher but regardless even shifting at 8k it should trap well above 120mph . i would hit the dyno again with the water on to see whats up.

 

Is it just me or is the power per RPM really off for what turbo he has...

 

Any more inputs? Need help guys.

 

It seems that power is quite poor in midrange - streetport also reduces midrange power. Just run more boost in midrange and taper off to limit peak power.

Your power is peaking by 7.5k rpms and it looks it would hold that power for very long extend. Ideally you would want to be over 7.5k all the time, range where most power is produced is producing highest acceleration for given speed, range of high torque plateau is only useful for acceleration in given gear...

 

You would really have to re dyno the car to see if there are any issues . Ignition break up etc will show up on the graph even if the car feels smooth. Just do 1-2 pulls with the water on to see where it's at.

 

right... what spark plugs are you running ??? maybe fauled the leadings and lost some power .

 

maybe the dyno is off. there are a few inflated dynos on the east coast.

 

Plugs are brand new, put in on friday. This is DR, not US. Dyno used was the dyno that reads lowest locally, other dynos would have hit 500+.

Guess i will just have to redyno with the water on

 

What specific spark plugs are you using?

 

You should have been tuning with the WI in the first place, I don't think its a good idea to run that much power without WI. The WI does hurt the power a little, and your 4.44 gears may be slowing down your trap speed a little too, and having a slow 60 ft time slows down your speed too. A bigger turbine housing would be better. More runs/practice at the strip will help too

 

Your torque on the dyno looks good from 5-8,000 rpm which is where you are when you are drag racing.

The dyno shows a pull from low rpm though which doesn't show the dynamics of the boost recovery/spool as you will see in actual driving.

Does it feel like it takes a bit for boost to come back on between shifts or do the tires break loose on shifts unless you are careful with the clutch engagement?

If the turbo has slow recovery back into boost you might have to work on techniques like flat shifting.

 

@ Rich.

Plugs are stock 9's all around

@Tom

I am tuned on pump gas mixed with 100 octane race gas. WI is something else that can failed so i tuned without it (but mixed) and added it later.

@BLUE_TII

The tires break loose on shift unless im carefull.

But i dont know the car doesnt feel like a 450whp should.

On those Nittos on that power i would assume i should break traction accelerating from a roll in 2nd gear hell maybe a little in 3rd but its not happening.

 

Yeah, I believe either that dyno is off or something with your setup messed up at the track. I pretty much have the same setup as you except I have larger primaries, dual ball bearing, stock 4.10, 11 heat range ngk, and have preturbo injection running 50/50 and on a mustang dyno and made around 450whp at 18psi (low boost) and ran my friend's supercharged 2012 5.0 that made 700whp and trapped 127mph in the quarter, I beat him by a car and a half. I'm assuming my low boost should trap pretty close to 130mph. I suggest checking your setup for loose plug wires or bad plugs or possible bad coil. O and I rev my streetport to 8500rpm. Edit...your clutch could be slipping as well on the track, I know my clutch has pretty much died now and I'm not putting the power to the ground anymore and it's noticeable on the street, so I can imagine how bad it'd show up on the track.

 

Ok I was wondering if you had race gas mixed in, did you happen to datalog on the dyno and at the track and see any difference in knock? Shouldn't you be running something better than the stock plugs, at least 10 heat range.

what was your half track trap speed??