1st Gen Chassis Dyno readings

R

rlekun

New member
I may have the opportunity for some Dyno time on my ITA RX7. Would others be willing to provide examples of their readings for comparison purposes? I realize your set-up is completely different then mine, but it would be helpful if I knew what competitive cars were getting at the Dyno.
I'd be happy to share mine.
 
Original stock motor, 120 K miles, multiple seasons of abuse. 117 hp. I have seen a known legal motor tuned to within an inch of its life pull 128 hp. Insides of a legal motor don't seem to make much difference. Tuning is a big deal. Going to check out the new motor in a few weeks, hoping to set the new benchmark.

How about you Rlekun?
BTW, did you get the run file from the dyno shop? Most Dynojet shops will put the runs on a floppy for you, and you can get a viewer from the dynojet sight that lets you overlay your runs with others.
 
Man....you guys make me feel soooo much better! I'm almost cometitive, and I dynoed at 106 rear wheel hp @7000 or so....with a motor with some bad oil seals. There IS hope for me!

Of course, the bad news is I have to find 20 more HP!

------------------
Jake Gulick
ITA 57 RX-7
 
Dave,

Not to that point yet. Car is still in the garage putting rear suspension (TriLink and G-Force Panhard) and new Fuel Cell in. I need to redo the exhaust before getting on the dyno since the back half of the exhaust got kinked when backing off the tire wall last year at M-O.

Can you tell I'm running a bit behind this year?
As soon as I have Dyno runs I'll provide readings, files, whatever! I probably wont make the May IRP race so the first double at M-O will be my first time out this year. See ya there...
 
I pulled a 119.9 with 102.2 of Tq. Bad part was that I had NO leading ignition and a bunch of crap in the Carb.

You can check out the sheets on my website...

www.balz.myip.org under the Dyno Day directory. I am dropping in a new suspension and will probably head out before our trip to VIR in May for another pull.

Frank
#67 IT-7
SE - Div
www.balz.myip.org
 
Thanks for all the input. Can't wait to see what my pulls are.

Related question...what are you guys paying for dyno time?
 
Dyno labs in Atlanta charges 50 bucks for "roughly" 3 pulls (he is very liberal with the "3") on Thursday nights and Saturdays.
 
I'm paying 125.00 an hr. Balz, comon, 120hp with no LEADING ignition. On a 12a? And I've got some prime ocean front realestate in AZ for sale.
 
The top Spec RX-7s here in DC pull about 105rwhp. That is with stock carb/intake, emmissions intact (one hiflo cat), and stock exhaust manifold.
 
First off...I really hate it when someone that doesn't know me from Adam's house cat questions my integrity, but I guess that follow's the character of the person making the post. You have access to my website, then numbers are there for you to see.

The engine did 153bhp at the flywheel, that being the peak number of 9 pulls, two weeks prior to the run that is posted on my website. We were expecting 125ish. I was NOT happy with the 119.9 so we pulled the plugs and they were slightly fouled...I called my engine builder and raised a little hell. The carb was a brand new rebuild, and he had no explanation. We put a timing light on the car and found there was no fire to the leading ignition. The leading ignitor was fried.

We replaced it took the car to the test day at Road Atlanta for a 1/2 day session. I got through 2 laps and the carb took a crap (later we found out it was our fault). I put my old "faithful" carb on and went out on cold tires and ran a 1:48 flat, our fastest time ever at Road Atlanta.

So, believe what you will, but the truth is above and the dyno sheet reflects the facts.

Best regards,

Frank
Tis better to be Rotary, then to be Pis't on.

www.balz.myip.org
 
Sorry BALZ, but I gotta agree with GEO46. Something doesn't seem right. I'm not questioning your integrity or dyno data, just your car's ignition. If I disconnect the leading coil wire or plug wires on my car, it noticeably runs like crap. Are you using a direct-fire setup? If so, the leading ignitor doesn't matter. If the engine isn't getting leading spark and is only getting trailing spark, then you're only igniting the fuel charge at the end of the combustion stroke. This is the same as drastically retarding the timing. (BTW-we met at the early March event at Road Atlanta.)
 
I'll double check but I am 99.9999% positive it was leading and not trailing...

As an FYI...take a close look at the dyno readings...if you are familiar with Dynolabs, every dyno sheet I have ever seen from them pretty much has a "clean" pull line. Mine looks like an EKG. Larry's first comment was "you have an ignition problem." We thought it was the carb (and yes, the car was running like crap).

Further checking (timing light) revealed the dead ignitor. I shall double check to see if by chance it was the trailing and not the leading that was toasted, but I am telling ya, I am pretty sure it wasn't.

Frank
 
I believe the leading ignitor was breaking up on the dyno. They seem to go in and out when they die. The car was running like shit on the top end that day. You can see on the dyno sheet how it was breaking up.

Also we run our timeing extremely advanced. Far more than most people set theirs. Our trailing is set well in advance of what stock leading would be. Probably several degrees more than what most of you run. this will make a differance in the way the engine runs without the leading ignition.

We where both unhappy with these dyno pulls. We where expecting around 128-130 RWHP. We'll see what happens next time. The car is running much better now than it was that day.

Mike
 
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