Car exhaust burbles at cruse ROE 710 cam

[pokeyl]

I hear you. Do you have a stock clutch? You might need to upgrade that eventually.. i did..I think the half shafts are good just don't like wheel hop. I

I am sure a clutch is in the future.

Also the new tune is in, seems better. It will be a month before I can get on the Dyno again.

[Hrysler]

I am sure a clutch is in the future.

Also the new tune is in, seems better. It will be a month before I can get on the Dyno again.

That's great! Let us about the Dyno again. I'm jealous:-)

[pokeyl]

I have another set of heads that I could have ported and sell if someone want them. PM me

[pokeyl]

update Still working, we have tried different tunes and no change. The stumble happens at cruse vaccume is around 8-7 inches, 1750 RPM engine warm in closed loop. But if I crack the throttle open (any amount) the vacuum goes up to 9-8 inch and car runs perfect. I have looked at all the data logs and there are on other fluctuations that would cause the car to start running so well. Even going up a hill will change the vacuum and smooth out the power. Any Ideas???

[Whiskey]

I have basically the same heads/cam on my Paxton Viper. The Roe 710R (710 and 710R have different specs....slightly).

I do notice in lower mph say 5-55mph the car isn’t as happy. It’s all low RPM, light throttle. Maybe I need to adjust my driving style to let it rev a bit more. I typically keep it in the 1500-2000rpm range when driving.

The Paxton and the cam come on about the same time and at 3500rpm all hell breaks loose as it goes from pulling hard to crazier to bat-shit-crazy-tires-struggling-I-will-break-loose-&-die-if-i-try-this-in-2nd-gear @ 6300rpm. If I recall I’m running 8-9psi and putting down 835-850rwhp (dyno numbers vary lol). The car never actually falls on its face. Peak power is at 6300rpm fuel cut. I only loose ~25rwtq from 5200-6300rpm. I’d love to rev this higher but need a dry-sump and it’s just too much money.

[Mopar'er no car]

950 +/- at the crank on 8-9 PSI? That is impressive.

[pokeyl]

950 +/- at the crank on 8-9 PSI? That is impressive.

That is inches of vacuum, not boost.

[Mopar'er no car]

That is inches of vacuum, not boost.

His post above mine says 8-9 psi boost 835-850 RWHP. Thats somewhere around 950 HP crank.

[Whiskey]

That is inches of vacuum, not boost.

Mopar’er no car is correct. That is psi of boost.

The Roe710R cam loves the Paxton. More or less at the limit of the Novi2000 poor little guy can’t give much more. Wish they still made the novi2500.

[pokeyl]

I also looked at the spark advance in cruse. along with the lower vacuum the advance is always above 30 degrees when the motor runs poor, so I asked the my tuner to pull some advance under cruse conditions. He removed 5 degrees from 1300-2200 RPM at vacuum below 8 inches. seems have helped some. This weekend I install 3 inch High Flow Cats and a Corsa 3 inch exhaust. I hope some extra back pressure will fix the problem. The 3 inch Mopar Exhaust has Zero back pressure. Results this week.

[pokeyl]

No change, car still stumbles in cruse, new exhaust has no drone, holds lots of heat, very sharp report at the exhaust tip, almost gun shot like! I may put the mopar race mufflers back on with the high flow cats.

[pokeyl]

I will have the Corsa back off the car this week. anyone need a set? $1200 plus shipping, stops the drone but just not for me. Cat-back with 3 inch outlets. Only used 63 miles (new but not) will come in factory package.

[pokeyl]

Old thread, but the fix was a new Inlet Air Temp sensor. Car runs the best it has in the 2 years I have had it!