TwinTriangles

Hey guys, Im looking to get tuned by a professional. Im lookin for someone experienced with the PowerFC timing for streetported motors and such, my fuel maps are all nice and tuned but its the timing I cant comprehend so Im interested in paying someone to do it. Where or who would be the best person to do it ? Im considering cruisin over to rx7store.net and and not concerned with the fact the its 700miles from here...
Anyone got input ?

myR1

iTrader: (1)

If you have a way to get it to columbus the rx7store would be a great choice. My car was up there last month. They are very easy to work with, and have a lot of experience with our cars.

TwinTriangles

Thats kinda what Im leaning towards... i think the 700miles would be a nice little drive too... Just wonderin if there was anywhere else that was reputable...

cavellm

Too bad you're way out there. Texas has a shitload of awesome, reputable tuners. Steve Kan, Chris Ott, Don Marvel, and a couple down in San Antonio, can't remember their names.

SleepR1

Nothing against Rx7 Store, but they couldn't do anything with my timing. My base map ignition maps were setup by Dave Barninger (KDR built my large streetport motor). Rx7 Store tuned my car by leaning out the AFR one point (from 10s to 11s). If you don't already, have a bung drilled into your downpipe, otherwise they'll stick a pipe in your tailpipe. The pipe has the lambda sensor on it. There's a 1/2-point difference in AFR between he downpipe and tailpipe. Be ready to spend the entire day there. With my tuning session (last Sunday Nov 2), they had problems getting their equipment to function properly. I got 7 to 10 dyno pulls, on their Mustang Dyno...my FD was heat-soaked all to hell. BTW, apparently the Mustang Dyno reports a more conservative HP number than the more popular DynoJet dyno. From my estimate, the Mustang Dyno reports 10 to 11% lower than a DynoJet.

TwinTriangles

So why were they unable to tune you timing correctly ? Ive got a Pettit large street port but I cant find anyone around here that is willing to even touch the timing on my car...

jeff48

The Mustang dyno DOES report a lower RWHP and (all things being equal such as Intake Air, Oil and coolant temps) is more consistent with real world experience. Because of the way the Mustang is constructed, it better simulates drag and weight, both of which reduces over RWHP #'s.

SleepR1

Actually Jason Baughman did try advancing the timing a skosh, but the slight advance, DECREASED hp, so Jason adjusted the timing back to where it was (which was retarded on the base map Dave Barninger provided with my large street port and mods). You can't mess with timing too much. There's a risk of blowing the engine. There's at least two FD owners on this forum, who have direct experience with timing adjustments gone wrong.

SleepR1

Yeah, I'm satisfied, that my FD makes 300 to 306 Mustang Dyno rwhp consistently even with extreme heatsoak. With the differences in dyno numbers being generated, I now ask which type of dyno someone has used to generate rwhp numbers. I even wonder what the value of dyno rwhp are anymore. Comparing RWHP numbers between different FD Rx7s is almost as useful comparing UTQG ratings between different tire manufacturers

TwinTriangles

Yea obviously you would only gain HP from a streetport if the timing was correct, and naturally it would need to be retarded to do that because of the larger ports, What im wondering is since he runs a race port with the PowerFC is if they at rx7store know the ropes of tuning timing well... ?

SleepR1

Rx7 Store will soon be tuning a race-port Pineapple motor (with Power FC) and XS Engineering single turbo, so you will have answer soon enough.

twokrx7

iTrader: (1)

SleepR1,

Sorry for the off-topic comment, but I'm curious about your experience with different afr results between tail pipe and downpipe locations.

My testing revealled identical afrs at either location and since I test and tune at the tailpipe only I am interested to know your results.

SleepR1

twokrx7,

Actually, I'm going from what Zavier (Rx7 Store guy) told me with regard to the difference in AFR readings between tailpipe and downpipe. Rx7 Store tuned my AFRs from the tailpipe. They were in the 11s with 15 psi boost from the J-spec twins and midpipe.

jeff48

twokrx7

Differing TP and DP (or MP) AFR readings can be attributed to many things. MY DP and TP AFRs are identical also but I have tested other cars where the DP (MP) and TP placements give different readings. Experience shows the following factors contribute to different AFRs.

If the TP AFR is ALWAYS leaner than the DP (MP) readings regardless of the car tested then most likely the after-sensor length of the TP sniffer is too short. The shorter the distance between the end of the test pipe and the outside air, the leaner the AFR due to blow back from the atmosphere.

If, from car to car, the tested AFRs differ:

1. The car tested still has a cat or other restriction
2. the car tested has an exhaust system leak in the DP or after
3. The exhaust tip where the sniffer is placed has a too large exhaust radius (5in coffee can type muffler tips for example).
4. The sensor is overheating in the DP or MP
5. The sensor is too close to the turbo outlet and the partial pressures are being affected.

HTH
Jeff

Jason

iTrader: (5)

There are 2 of us here with large street ports and single turbos and the majoroty of the cars we tune are ported motors. I have tuned my car to 506 RWHP and Zaviers is 460 RWHP. That is thru adjusting timing values and AFR. The nice thing about tuning on a dyno is you can really fine tune the timing maps.
When I was tuning Mannys car I was having problems with our dyno and could not get a good reading from it. I was reluctant to change the timing much do to that.

Manny I did adjust your timing and split a little. Daves timing map was really conservative with a lot of timing pulled out up top. There are a couple of spots were I advanced it about 4 degrees.

Jason

Jason

iTrader: (5)

Since the dyno was not reading correctly I would say you are well over 300 HP. Our Mustang Dyno is calibrated to read Dynojet numbers.

Jason

SleepR1

So Dave retarded the timing a bit much at the higher rpms, and thus you advanced the ignition timing a skosh (4 degrees) up top?

All I know is that when I get on the gas, my car leaps forward, and the tach needle moves very quickly to redline after 3500 rpm

SleepR1

I may take Zavier's offer to do some more tuning spring 2004, or when Ryan picks up his FD from you...

Jason

iTrader: (5)

Yea, come over with Ryan and we can get some better numbers for you.

Jason

SleepR1

SleepR1

See this thread

https://www.rx7club.com/showthread.p...64#post2511664

Xcessive

I look at the AFR testing this way. The factory puts the O2 bung where there engineers figure it should be,
and I think the factory is pretty knowledgable.We measure all cars, from the outlet of the turbo on the down pipe only, because there are to many variables
about the measurement further down the system.
I figure especially with the temprement of the rotary
I need all the precision possible. Just my 2cents
Thx Ralph

SleepR1

If anything, the AFRs will measure "leaner" at the tailpipe, than @ the downpipe, so perhaps my 10.9-ish, 11-ish @ the tailpipe is 10.5-10.9 @ the downpipe...

phlanigan

FWIW, my Techedge WB with sensor at the stock location always seems to read about 0.5 AFR richer than a tailpipe probe. This was the case when I was running a stock setup and now with my single turbo. I have a stock main cat with the airpump connected. I don't have any exhaust leaks and I've always ensured that the tailpipe probe is placed deep into the exhaust.

SleepR1

Yeah, that's what Jason and Zavier mentioned, so if anything the tailpipe probe is a more conservative AFR reading...?