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I wish my street trim e.t was at least somewhat close to my race trim e.t. I am almost a second faster on race gas. What about you guys?
 

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Yeah, tell me about it.
Street trim : 12.85 at 112.8
Race trim : 11.39 at 126.1
 

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Resident Idiot
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That used to be my formula. I would run 13.5's (18* timing) in street trim, then 12.5's (26* timing) in race, same tires too.

Then I figured out, my car was horribly out of tune with a street chip, because once I switched to a MaxEffort, I got into the 12.5 - 12.3 range in street trim.

Now, will I go 11.5 in race trim now? No, but it's in much better tune, and cranking the timing and octane UP, will create some improvement, just not sure how much.

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Email Address: mailto:[email protected][email protected]</A>


Current Combo: Stock Turbo, V4, MSD50's, TH DP, JayJackson 62mm TB, 16position MaxEffort Chip.
12.35 & 108.39 Street Trim.
 

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I want a Z06
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3timesT, why are you so much slower on the street? 126mph to 112? You must be running 30psi and then 16psi or something??

[email protected] Race (Race Gas + 26Degrees

[email protected] Street (Pump Gas + 18 Degrees)

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Mike Schoenfeld
 

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3timesT, why are you so much slower on the street? 126mph to 112? You must be running 30psi and then 16psi or something??

[email protected] Race (Race Gas + 26Degrees

[email protected] Street (Pump Gas + 18 Degrees)

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Mike Schoenfeld
Bringing this back because I never answered TTA89 lol. Jeez I've been MIA for 7 years. :eek!:

Your assumption was right on the money!!!! Now for the reason for this huge difference in boost. One word......FLOWMASTER.

Capped up I was running through a 3" single muffled by a Flowmaster muffler and seeing 16 psi.

Uncapped, the boost went to 27psi in 1st & 2nd gears and 30psi in 3rd gear. No changes to the ATR external wastegate mind you.

14 PSI of back pressure through the Blowmaster.

I was running a RA race chip and a tight Pat's 2800 converter. This caused the car to be a dog to the 1/8th mile (97 mph). When I hit 3rd the car woke up and even though she lean popped 4 times through the intake (340 pump but not an M) she was able to run 126 mph in the 1/4. The non 'M' 340 pump can't handle 70+ psi of fuel pressure, the M does. I was running about 41-42 psi FP with the hose off at idle.

Had a grudge race with a buddy's 80 Z28 (468 BB) so I capped the exhaust back up and cranked the waste gate to 25 psi. Ran an 11.5 at 121 or so and beat him by a couple of cars. After the race I was seeing bubbles in the overflow tank so I knew I popped a gasket. Hmm let's see...25 psi on top of 14 psi of Blowmaster back pressure..........39 psi. :cheers:

Shortblock was stock 109, .020 JE pistons, stock rods with ARPs, stock crank, 2 steel caps.

Top end was ported 1.77 heads, ported intake, stock TB, ESP stage 4 cam.

Induction was a 9" K&N, 3" MAF pipe, stock MAF with screens (RA says to take them out with the race chip), Limit T63e, KB Big Boy (lol).

Exhaust was an ATR 3" DP with external wastegate, stock manifolds and 3" single.

Drivetrain was a slipping and stock 2004r out of a 307 powered car, Pat's 2800, stock rear. Tranny wouldn't shift higher than 4000 RPM when left in D so I had to manually shift off the stock tach. lol

Suspension was all stock including having the front sway bar in.

Wheels/tires were stock fronts, Welds and 27x10 M&H slicks in the rear.


With a 340 M pump, real tranny and a 9'' non lock up she would have easily ran 10's at 130.
 

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Mines the same, give or take an mph or two. :dunno:

Pump gas and alky. so you only need to tune once. :yup: :cheers::6::headbang:
 

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Where have you been? shouldn't take that long to tune the car... your probably due for an oil change by know....:eek!:



Wish I could take 7 years to answer the wife when I come home late :D



Welcome Back.

:cheers:
 

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Where have you been? shouldn't take that long to tune the car... your probably due for an oil change by know....:eek!:



Wish I could take 7 years to answer the wife when I come home late :D



Welcome Back.

:cheers:
You can...it's called divorce. lol
 

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well the only thing we change between street /race is the tire pressure:wink: run 9s @ 138+ and then go out to eat :headbang: oh... pump gas and alky :sw:
 

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Older than dirt
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340 vs 340M?? I think the difference is the machined inlet for use of the filter sock.. not a performance difference...
 

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I believe you are correct. I know Walbro used to make a 255 L pump in both low and high pressures. I know it was a 255 L pump but it wasn't the high pressure one and fuel flow would significantly diminish as the pressure went up. I should have just just put a RA XP pump with the stronger bypass spring in there from the get go.
 
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