Unhappy Helcat Owner

Was at a car show this weekend.. there wasn't any advertising nor any plaques nor judging, no cost to get in or view but word of mouth generated over 75 cars ..and some of them really cool. I think 7 MOPARS were there which is good for this area and there were a lot of spectators. ..and it didn't start at 8 am..and it was about 23 degrees..not too hot or cold..

There was also a dyno there..free for anyone who wanted to use it..and a Hellcat did...actually, he probably spent over 1/2 an hour on it. The power comes on so smoothly but it isn't loud enough for me..   anyway, the best he could manage was 619 HP and 585 lb/torque  which is well below the claimed 707 hp and 650 lb-ft . I would be going back to the dealer...

Sorry for the quality of the image...it is from my phone on low res..

Ian

I'm guessing 619 at the wheels is right on for 707 at the crank. Was it a stick car or auto? My wheel hp calculator shows 619 = 731 at the crank for an auto equipped car. I did watch a show on TV that showed the cars were slightly under rated, but old brain can't remember what show it was...

http://www.mk5cortinaestate.co.uk/calculator4.php

I thought the 707 was supposed to be at the wheels...

It was an auto...

Well grassy I googled how factory hp levels are suppose to be measured. Each car line must be dyno'ed individually with it's own stock exhaust and all accessories. And shows it's at the crank.  I went to wiki.com and searched it as I wasn't sure myself. This is what I found below. There is a lot of different findings out there, though to no surprise eh.

In 2005, the SAE introduced "SAE Certified Power" with SAE J2723.[26] This test is voluntary and is in itself not a separate engine test code but a certification of either J1349 or J1995 after which the manufacturer is allowed to advertise "Certified to SAE J1349" or "Certified to SAE J1995" depending on which test standard have been followed. To attain certification the test must follow the SAE standard in question, take place in an ISO9000/9002 certified facility and be witnessed by an SAE approved third party with all stock equipment as installed.

HP ratings are measured to the SAE standard - which specifies BRAKE HP, ie using an engine brake dynamometer. There is no Society of Automotive Engineers standard for wheel horsepower, and we all know that chassis/wheel dynamometers give wildly inconsistent results depending on brand, type, and calibration. Similary, european DIN HP standards and japanese JIS HP standards are specified using engine brake dynamometers.

Funny. I don't think they told buddy this..he did not look happy...

I think giveing HP at the crank is an absolute cop out.  The American outboard industry got it's butt kicked by the japs years ago..we had a Johnson 20 and we were at some sort of a show and picked up a Suzi 20 hp cheap...it blew the doors off the Johnson...why, the japs measured the hp at the prop and OMC measured it at the crank.. which would you buy ?

Crank HP, as you mentioned is useless.. what I want to know is what is happening at the rear wheels..everything else is marketing and guessing.

I agree with you about the dynos and have questioned the ones that show up at shows..but as my son says, the better ones actually attach to the rear hubs vs rollers..anyway, it is a spectacle.

Anyway, too bad for this guy...

My engine builder tells me you have to take dyno's with a grain of salt. They are all set up differently and the guys run them a certain way too. He has had some engines come from the USA with a dyno sheet that a customer has bought as opposed to getting it built by him, that says 900HP then we put it on his dyno and it makes 750? i guess the rest got left at customs. lol

Weight and mph in the quarter mile will tell you the real hp of any engine that day at the track.

Grumpy427 wrote:

Weight and mph in the quarter mile will tell you the real hp of any engine that day at the track.

Nah..then you are dealing with other problems..altitude, temperature, humidity track cohesion, tires, etc..

HP numbers are a moving target so I don't get caught up in them however, when you advertise hard at 707 hp...

On the flip side, many European car makers (and i think a few American cars) underated the horsepower of their engines..

Math and physics dont lie..