crispeed

Hey Steve!
I can see the 10 sec timeslip allready!
In a 1st gen with 560RWHP(dynojet) you should do betwwen 135 to 140mph with no problems. Both of my buddies 12A turbo powered 1st gens ran 10.38@131mph and 10.50@135mph with 460 to 500RWHP!

crispeed
87 Rx-7 TII
9.204@150.47mph
2600lbs
un-tubbed

zyounker

Or by maybe running to hot a plug causing pre-ignitions?



That was my point..
.

AJC13B

Anthony - Thanks mate! I have been given a few part numbers to try, will see how we go. What mixtures do you usually run C16 at?

Greg - I will be using American Racer 26x8x15

Crispeed - The 560 might be optimistic, but the dynojets usually read a little higher than Aussie dynos so I am in the ball park I just have to drive it properly now The car might have a little left in it yet, lean back the mixtures to 12.0 I have been told and the car should pick up a few ponies

Anthony Rodrigues

AJC13B,
Can come back to 12.4 at that boost, can also add some timing. Keep an eye on EGT to ensure you do not go to far. 30psi should be safe with C16. Have seen 36psi, split the crank down the guts. Turned the boost down, but didnt fix it. DAMMM!
Is that the biggest tyre that will fit Gen 1????
Anthony

AJC13B

We had the EGT on it and was measuring around 750c. The sender was about 6 inches after the turbo.

Bill said to lean back to 12.0 minimum but keep boost under 30psi. The engine will hold 30psi, but the seals have a habit of sticking in the rotors if there is a misfire and boost is 30psi+

On one power run we saw 380kw but boost was 29psi

Could get 8.5s under there at a squeeze, but yeah that about it.

waynespeed

Congrats on you new HP numbers!!
With around 465 US dyno horsepower you should run mid 10's. I guess this is around 395 AUS RWHP. You should look more for 9's with over 550 US HP. I wonder what numbers you guys get when you dyno a stock series 6, 187 HP?

RICE RACING

Hey Steve, nice work

Your data is very linear, 26psi/22psi =1.1818 sqrt =1.087

1.087 x 433 rwhp (your last no @ 22psi) = 470.7rwhp ! That is what you should have got at 30degC ambient and 300m above sea level. (test condition @ summernats comp)

I thought it (your dyno in sydney on a cool night) would have been a bit higher due to the higher ambient air temp here in summer and the higher altitude in canberra ?

I recon with a CDI you would be around 500rwhp based on your result in Canberra at that boost level, but there can be majour differences between dynos as you know.

Hey run the 36 psi Anthony has 36/22 sqrt x 433 = 554rwhp or 650rwhp american slip crank is not much fun though

crispeed

One thing that's always accurate and rated equal anywhere in the world would be the ET in the 1/4 mile!
It takes a certain amount of power to do a certain mph per total weight of vechicle!

crispeed
87 Rx-7 TII
9.204@150.47mph
2600lbs
un-tubbed

RICE RACING

Lots of variables in this though unless you are a hardcore drag person with "ultimate" set up for launching of the line.

Far more accuarate method I use is in gear acceleration at moving speeds, say 80mph to 100mph...this negates things like excessive weight (to a degree) variances, majority of traction problems and lets you compare "deliverable" power wether it be a circuit tunned or drag tunned car. You cannot cheat these figures, on road acceleration, no correction factors, no dyno variances, NO EXCUSES

I understand that, MPH in the quater is a good indicator of this as well ? but as I do not race in this field I am not sure how much the Launch has to do with the final MPH, I assume it would be worth around +10% to the final trap speed if you can get all the power you make to the ground on the launch. Wich will greatly influence the MPH, hence give you either an optimistic or under rated guess as to the power you realy have?

Hence I find the in gear higher speed measured acceleration by far the best indicator of how much "average" power you ave. Wether you can use it to get around a circuit or down the quater is another science all together which is of not much importance to an engine builder such as myself as long as it lasts the design time then it is up to the chassis engineers and tunners to harness what the engine can make !

jkekeisen

Hey AJC13B,

would you happen to have any stock (3rd gen) dyno runs on the Dynamic Test Systems dyno???

or maybe you know someone who has them???

thanks,
jkekeisen

AJC13B

Waynespeed - Yeah a standard RX7 makes around the 180rwhp mark on dynos here.

Rice - The dyno at Summernats was on the optimistic side to say the least. I would say the car made 400hp at the treads that day. After speaking to Bill, I am of the opinion that if we moved back to Avgas, we would actually pick up HP. My engine doesn't like alot of timing, it only has 10 degrees up it at WOT and thats on C16! Maybe with CDI we could run a little more timing, but I still think the C16 is overkill. Its been tuned now so I won't bother this time. If there is a next time it will be tuned on Avgas and I can spend the money I save on a CDI

crispeed - It gives a pretty good indication seeing as hp is the ability to move one pound one foot in a second I think...

jkekeisen - Don't know of any, sorry mate.

The_HITman

I will add a little more detail to the post.

Steve's engine ended up on around the 9 degree Lead mark, but it depends on the boost level as to the timing values of course. Trail split was around the 6 to 7 degree mark where it produced peak power. Timing changes in either direction by both Lead and Trial cost HP, so it is tuned to the last degree. Mixtures were around the 11.8 to 12.0:1 mark on the C16 fuel. I was not willing to go any leaner than this because the motor is a street driven engine and has to last more than one meeting. The mixtures are constant at that level across the entire rev range and measured with an M&W EUGO system (very accurate and repeatable) with the sensor sitting right next to the EGT sender. EGT's around the 700C mark were consistent with each run which also ensures the mixtures were reading consistent too. We could have maybe gone to 12.2 to 12.4:1 but with 12.0:1 the engine was running clean and sweet and very little power (5hp) was made going from 11.5 to 12.0:1, so I figured if we were down 5hp it was worth it to keep the motor alive. We must have done some 20 pulls at that boost level and the key to keeping it running I believe is that Steve's cooling systems works rather well.

Some will be surprised, myself included, that the stock BUR9EQ plugs all round gave good results on the stock Series 5 ignitors and coils. Switching to B10EGV plugs gave misfiring problems even at 0.6mm gap. I believe there is another maybe 10 or 15hp in going to CDI at his boost level of 26psi. Running 30psi and CDI should see the motor go another 50rwhp and easy see his car in the 9's. I suppose it goes to show just how well stock ignition works!
the 9 heat range to me was a little hot but the plugs were coming out looking very good and not overheating. This is probably due to the motor running around the 70C mark through all the runs. If it ran in the 90C range as most engines do he would have needed 10.5's or 11's. There is probably another handful of hp in getting the motor a little hotter to help with fuel distribution, but the reliability so far has been more worthwhile.

Any questions ? :-)

Jeff20B

iTrader: (13)

Yeah, off topic though. Have you been messing with NOT-20B at all lately? How's your rear rotor?

Anyhow, that's some cool info about your dyno runs. So the BUR9EQs actually performed better huh? I'll have to remember that.

Anthony Rodrigues

Hitman,
Not Flaming, just curious. Similar mixtures/Boost & egt, but no problems with spark misfire using R6725-115or105egv's, still maintaining std FC coil packs with MT8. Could you increase the dwell, to increase the spark? The reason I ask is because I do a few Haltecs and have not come up with this problem. I was under the impression that the plug heat range was more determined by chamber temperature and not water temperature, they are definitely not directly relative. I would be interested to theory behind this.
Regards-Anthony

RICE RACING

I am of the belief that the charge temp is super critical to the tolerance against detonation. Did a test on one car with b9's at 8deg ambient and one bar boost but intake charge temp was around 70degC combined with a/f of 12:1 on pump type gas and boom !

Rich mixtures will help to combat the "glow plug" effect of to hot a heat range. The engine temp does play a big part as the plug transfers heat from its working surfaces to the rotor housing and hence there is a greater and quicker heat flow potential the cooler the water temperature of the rotor housing, hence he can get away with 9's.

Steve get a CDI you cheap ***

The_HITman

Anthony. I set Coil Charge time is as high as those coils will go before saturation, which is around the 5.0ms mark. I actually found at high rpm that they respond to a little less charge time which is probably due to a duty problem, but this is only at extreme rpm (sustained 10,000+). Different plugs were intended to be tried and tested, however the usual time restrainsts prevented this. The R6725's were already a thought and so too were a couple of others. In the end the BUR9EQ's were readily available and have been working fine. I personally have not been having any trouble with B10EGV's or hotter in other engines but this coulld be related to engine temperature being hotter in other engines. Maybe a B9EGV might have run better for Steve that night.

Rice pretty much covered my thoughts. The chamber temp is indirectly effected by engine temp because of how quickly the heat can be drawn away from the combustion area. It is exactly why we can get away with 9's and not have anything go belly-up. A smaller part of the problem here is that the rotor surfaces are cooler from the intake section through to combustion which does effect atomisation. The best way to see this is with methanol in how the hotter engine temps seem to help alot, and cooler engine temps tend to cause slightly erratic running. I believe Steve's motor could have made more power if the engine itself was running hotter, but this would have led to us needing 10 or 11 heat range plugs to keep things under control.

Rice you got another thing right. If Steve were to maintain racing this engine he should be running CDI at the boost levels he is running now. The combustion so far has been rather clean but he is running on the edge.
From what Steve is saying, if he gets a good time at the next meet it will be all the racing his car sees, and then the boost will be dropped back. For this reason you can see the money he needs to spend to get the ignition any better is not worth it for a one time run. If we could have dropped the BUR9EQ's plug gaps down maybe 2/10ths they would be more than sufficient for maybe 29psi. Then again, if we see him run a 10.0 or 10.1 we all know he will be back and wanting more ! :-)

On pump gas I would have aimed for 11.3:1 at 70C charge temps and map the system to run a touch leaner with cooler temps. The small loss in power as the temps rise is not usually worth the reliability risk in my books. A "little" ignition retard under boost at high temps goes a long way too. It may bring up EGT's but combustion temps are not quite so effected.


Jeff20B. Never had any rotor problems. Spun bearing after hitting the sump on the road and loosing oil, while having the factory oil pressure gauge fail is just bad luck. I am hoping to get it back together very soon and the motor can spend the rest of its days going for weekend motorbike hunts in the hills. :-) Never been much of a drag racer myself but it might see a few sprint days with a car club or two. I am looking forward to playing around with it again after having fixed a number of niggly current problems I had at the time that were causing a weak spark. All fixed now.

Jeff20B

iTrader: (13)

Oh ok. I just read through your latest updates last night. That's really great news! Man, I remember you messing around with your engine and three carbs back in late '97 I think it was. It sure has come a long way! Heh, even a local rotary guy named Ken at Mazdas & More has a pic of your car at his shop.

Not to take the thread off topic, but did you ever find another host for your videos?

AJC13B

What Matt said

AJC13B

Okay there are the dyno sheets.

Notes:

Disregard RPM figures in all sheets.

472_2.jpg - Boost is absolute KPA, take 100 away and you get 172kpa which is around 26psi

352_1.jpg - These are the 3 mapped power runs.

Power figures - I am unsure how the DTS dyno calculates engine power vs wheel power. To run the mapping mode, you have to 'configure' the dyno with some runs up to 100km/hr and coast down. From this, the dyno 'calculates' drve train loss. I do not believe my car has only 15kw drive train loss. Which figure is correct? I don't know. Next week the car might have a quick power run on a Dyno Dynamics chassis dyno to see what figures it spits out and we will compare.

Anthony Rodrigues

Hitman,
Thanks, for the reply!! Just looking at the sheets, I would normally blame that Top end squiggle on the start of an ignition problem. I normally reduce dwell to 3.25ms on anything that will see 8k+. I probably to not have the same data on temps vs heat range because I like to run a combination of C16 with additional injectors for Alcohol, when the boost gets up that high.
AJC- be keen for my own comparisons to see a back to back with DTS vs DYNO Dynamics. Your going to need a tyre to hang on to that. Good luck!
Regards-Anthony

Micro-MoTeC

Great figures Steve..

Should be alot of fun for you at the next meeting

Good Luck!

ROHAN AMBROSE

Anthony , seen those RPM figures on the dyno sheets thought for a minute they were drinkin more burbon than us on the dyno !!! Thanks the car ran crisp all weekend at Phillip Island , clean all the way , seen 11800 a few times , loved it ! 3 out of 3 wins .

Anthony Rodrigues

Rohan,
Congrats on the weekend, all we need is the championship and our theory on god will be true. That Guru centre bearing must be hanging in there, well done!! Better start packing those bags, looks like another Orlando and NJ trip in the near future.
Regards-Anthony
P.S- Our tuning secret is out, Jim Beam tunes all of our engines!

AJC13B

Anthony - So it was Jim Beam in the tank at Heathcote that day, not nitro as everyone seems to think??

The_HITman

Anthony,
The car did have problems with traction too, which may have caused some of the top-end wiggles in the graph, even though it was run in 4th gear on sticky rubber.

Charge time was dropped as low as 3.5ms but made no difference so it was left higher. The ignition is already marginal at this output which was evident in how temperamental it was with spark plugs.

It is good to hear some intelligent feedback for a change. Most of the time on these and other forums people only want to jump down your throat and scoff no matter how good or bad things are, and it usually comes from people who are novices at best.