2.9 Whipple + 5.3 MMR Stroker Dyno Numbers

[anjin]

update on the Stealth Cobra MMR rebuild

Deja vu all over again.

Got my MMR motor back and car built and tuned in time for Road Atlanta March 11. Very similar build to Hangman's - 302 stroked, stage 3 port, 80# injectors, dual GT Supercar pumps, LFP 1700 CFM big mouth, 9" crank 3 1/2" snout pulleys = 635 to rear wheels, plus built for road track with UPR chromoly front K&A's, UPR caster/camber, coil overs, Kenny Brown rear stabilizers, roll cage, etc. See link in signature for pics and details.

Made it one 20 minute session, came off smoking and clanking. Sick to my stomach as I loaded it on the trailer. Talked to Nergal then Mark. After we got past the initial "you must have had a bad tune" discussion (I have documented data logs - good idea by the way everyone for these discussions) began to look like overheat and piston swell on Road Track for MMR motors that are usually accustomed to 10 second runs and 20 minutes of cool down.

YES I DID buy the $300 warranty! Another MUST DO by the way. MMR stepped up and paid shipping both ways and covered parts and labor. Kudos. Sure enough .003 is right for drag but too tight for Road Track, and the Electric water pump they recommended had to go. Rebuilt at .004 clearance, and am putting on Stewart water pump, custom 3 row Tapp aluminum radiator and remote oil filter and cooler. It's all about getting better cooling and more piston clearance for all out all day racing. Words to the wise for any of you that race your Termis!

I expect to be back on the road in a couple weeks, next track weekend with NASA will be in September. Cheers.

 

[brainpa]

Did MMR inquire as to your specific application during the ordering process?

 

[anjin]

They didn't inquire but I relayed this information on multiple occasions and was ordering components specifically related to the application. For instance the Meziere electric water pump was not cheap but ordered it so that I could "continue to circulate the water with the pump on and engine off between run sessions". Lesson learned is that you have to make SURE that the sales guy is relaying the information to the build guy.

 

[SJ SNAKE]

Glad to hear the beast is back on the street :burnout:

 

[Turbo96'Cobra]

OP-When are you going to be heading back to the dyno? I hope thats it going to be an evening oe early morning session this heat is insane right now!

You running a non return system right?

 

[anjin]

Couple of mods since last update are as mentioned above Tapp radiator and also APR Carbon fiber wing, pics below.
2003 Stealth Cobra - inmanhome's Photos | SmugMug
Tapp radiator has beautiful tig welding and .080 aluminum and other strength benefits over the similar Fluidyne models and Russell will custom build and usually match the Fluidyne price. In this case we went from a 25" to 26" wide core, keeping the mount points the same for that little bit of extra cooling.
2003 Stealth Cobra - inmanhome's Photos | SmugMug
Compare 3 row radiator with OEM single row side by side
2003 Stealth Cobra - inmanhome's Photos | SmugMug
Removed the functionally useless spoiler, body shop friend plugged the holes smoothed out and painted the trunk lid, then we installed an APR carbon fiber wing that applies about 200# of downforce at 80mph, 500# at 120, helping keep the light rear ended Cobra from oversteering
2003 Stealth Cobra - inmanhome's Photos | SmugMug
For daily driving I remove the wing just leaving 4 small black aluminum mount pads on the trunk lid - back to "Stealth mode" ;-}

 

[Hangman]

OP-When are you going to be heading back to the dyno? I hope thats it going to be an evening oe early morning session this heat is insane right now!

You running a non return system right?

Whenever the engine is back from MMR, then it gets dropped in car and dyno time. Probably a month to be honest. It has been pretty damn hot outside, I will update whenever I hear news on getting it back.

My fuel system is a return style setup btw.

 

[MysticRob]

Hangman, I'm digging this thread back up to point out that what anjin posted above, and repeated here, sounds very much like your current problem in your other thread that I just posted in. This, combined with MMR's apparent lack of knowledge on just how much oil should be in the longblock they provided (gleaned from your question in post #40 of this thread) really makes me wonder if MMR knew what they were doing when they built that block.

From anjin's post:
"Made it one 20 minute session, came off smoking and clanking. Sick to my stomach as I loaded it on the trailer. Talked to Nergal then Mark. After we got past the initial "you must have had a bad tune" discussion (I have documented data logs - good idea by the way everyone for these discussions) began to look like overheat and piston swell on Road Track for MMR motors that are usually accustomed to 10 second runs and 20 minutes of cool down."

 

[2001mustang4.8L]

5.3L MMR shortblock. How did the repair go? You know I would like your opinion because I have to make a decision today on whether or not to cancel my original order and go with the cast iron stroker block 5.3L for the extra 40HP advertised. Wouldnt you get more like 70HP more because its 40HP for .4 and like 30 for .3? What do you think if I am going to be superchargin it anyways and can just get my hp that way.