Way too much boost pressure. ..21 PSI
 

Hi,
I hit 21 PSI today. Check light went on.
This really scares me. DTK 62mm sc pulley, tighed1´s DIY wrap kit and gatorback belt. DTK tune and TCU, rev limiter 6700.
Didn`t expect boost pressure that high.
Fortunately we have 102 octane pump gas here in Germany (about 95 US equivalent).
What do you guys think is a safe AFR at this level on 95 pump gas and what not :-) ? Can the engine (rods, bearings) take that level of boost for a long time?
I probabely have to change SC pulley back to 65 mm. Very soon.
Thanks
Steven

Re: Way too much boost pressure. ..21 PSI
 

11.9 to 12.2 ran that for years and 21 psi think you are only there for less than 10 seconds unless you are on the autobahn then you should be 11.7 to 11.9 jim

Re: Way too much boost pressure. ..21 PSI
 

Thanks Jim!
My thoughts: around 12.0 for best power and 11.5 for safety purposes.
I am still not sure about the Autobahn.
How about the cylinder head gaskets headstuds? 21 psi ond a stock base is pretty much, isn`t it?
I don`t want to add big crossoverd manifolds and headers to reduce boost pressure. But it seems that i have to. Otherwise i have to change to 65mm, to be much safer.
Thanks
Steven
Berlin Germany.

Re: Way too much boost pressure. ..21 PSI
 

Re: Way too much boost pressure. ..21 PSI
 

agree ,with woody,, along with ,with the crossovers your AFR's will go up,,you will need to add fuel. jim

Re: Way too much boost pressure. ..21 PSI
 

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Re: Way too much boost pressure. ..21 PSI
 

Are u getting p0108 over boost of map, with 21psi?
Did u change out the factory map 1.5 bar to another map sensor that can handle more boost

Re: Way too much boost pressure. ..21 PSI
 

Yes, P0108 every day :( when hitting to hard. Didn´t change the map sensor.

Re: Way too much boost pressure. ..21 PSI
 

Jim, not stacked. Just the 62mm pulley. Was stacked before on a different car with crossover manis and custom exhaust. Maximum boost i ever measured before: 21 PSI (166/65). Had to rise fuel pressure up to 5.1 bar aprx 73 psi not to lean out on the Autobahn. But no code at this time. Again, this is a new car. I want to keep it simple. But I see, i cannot :-)

I am waiting for the SL55 fuel pump tomorrow and a new fuel filter and I have to weld a bung to the exhaust for my Innovate wideband controller to see whats going on. Obviously the engine is in good shape and no belt slip on the pulley. I don`t want to hurt nothing.

Re: Way too much boost pressure. ..21 PSI
 

Oh, no! Please no restriction to the inlet :-)
One more question. 21 PSI @ wye are aprx 18-19 PSI @ the intake manifolds?

Thanks
Steven

Re: Way too much boost pressure. ..21 PSI
 

Lots to consider. I ran with 22 psi for a weekend. My difference in 1/4 mile times between 19 psi and 22 psi was hundredths of a second. My car was much stronger in the lower rpms and slower up top. The extra heat produced and horsepower consumed spinning the supercharger outside its efficiency range negates much of the power from the extra boost. As long as the fueling and tune are good I wouldn't worry running 22 psi however. The fuel used changes the AFR's. Pure gasoline gives one reading. 10% ethanol leans it out some. 104 oxygenated fuel reads much leaner on the wide band. I like to have AFR's in the high 11 low 12 range. You make more power 12.5 to 12.8. Not advisable. Do you know your AFR's? I'd worry more about the 6700 rpm.

Les

Re: Way too much boost pressure. ..21 PSI
 

Les.

honestly i see the transmission not shifting at 6700 rpm. The TCU was advertised shifting @ 6700 but my rpm gauge shows mostly 6100-6200. I have seen once 6400 on the first day, but never again.

https://www.ebay.com/itm/NEW-TCU-tun...sAAOSweWVXd2Q6

I bought a package pulley/ ECU tune, TCU uniit/tune from this guy. I don`t want to say any bad, because the car is running like hell but the communication isn`t the best, to say at the least.
BTW It is a specific tune for the 62mm pulley, he promised i should be safe with the AFR´s

I haven`t logged AFR, because the car is running about a week since i bought it. I have to weld the bung for the wideband tool as soon as possible to know what´s going on.

Steven

Berlin Germany.

Re: Way too much boost pressure. ..21 PSI
 

I think the higher the octane 98, 104, 109 pure gas the more oxygenated it is meaning u run these octane u would need more fuel, and or car would run leaner on these fuels? Right??

Re: Way too much boost pressure. ..21 PSI
 

I checked the TCU you linked. It shifts at the stock shift points unless its in manual mode. In manual mode it holds the gear until you command the shift or it hits the limiter. Our car has 2 limiters. The engine rev limiter (ECU) and transmission limiter. (TCU) Both have to be raised to take advantage of the added RPM's set on one or the other. I had a similar TCU once. (Evotech I believe) I wasted my money. Couldn't keep off the limiter because the shifts in manual mode were sooooo sloooow. Shifted normal when left to shift in drive.
I'm back to stock shift points. I will say that the power curve was still climbing at 6400 rpm and believe 6700 would produce 40hp over 6100, at the least.

Les

Re: Way too much boost pressure. ..21 PSI
 

Les,

even in manual mode (W) i cannot see 6700. Same as in (S) as stated before.. The shift points are nice though and very quick.

There are more negative effects:
1. I cannot switch between M (W) and S during driving. Once M mode is activated, I am allways in M mode until I stop the car and start again.
2. The downshifts are kind of rough when the automatik downshifts by its own. especially from 3 ->2 and 2->1 doesn`t feel as smooth as with the stock software.

However the car feels very fast. I can do unstoppable never ending burnouts from traffic light to traffic light when starting in M mode :-)

Re: Way too much boost pressure. ..21 PSI
 

i assume u know the s & w s= all 5 gears w=car starts off in 2 gear ( unless wide open throttle that overrides and car starts in 1 gear,, some say summer and winter like sand and or snow
u should be able to switch s to w while driving when you stop your car will switch to whatever you have S or W
the hard shift when slowing is normal with that tcu it is made to make more pressure on the clutches but you will only notic it when slowing like slowing for a red light. I have a stock tcu i'll trade you LOL

Re: Way too much boost pressure. ..21 PSI
 

[QUOTE=amx1397;922142]I have a stock tcu i'll trade you LOL[/QUOTE

hahaha. yes. thank you. nice offer :-)

Yes i know the difference between W and S.

But maybe i missed something? I thought only the W = Winter mode was programmed into the M = Manual mode and W is no more active. S works as usual. That´s how they do it here in Germany with the TCU´s.

Again, i can switch between W and S, but once M mode is activated in W, I have to stop the car and start again to have a (stock) by itself shifting automatik transmission. (only in S possible).

Anyway. I will test this out tomorrow and let you know.

Thanks

Steven

Re: Way too much boost pressure. ..21 PSI
 

Ok. - As i thought - Manual mode only possible in "W" (holding gears). In "S" the software is not holding gears, downshifting as usual.

As far a i understood the TCU limiter is raised to 6700 but obviously the tune is not. Anyway. I agree, it doesn`t make too much sense to shift @ 6700 with a 62mm pulley. The SC is way out its efficiency.

Also i am afraid that the valve springs will not hold the pressure @ 21 psi @ 6700 for a long time ->. Valve floating.

Steven

Berlin Germany.

Re: Way too much boost pressure. ..21 PSI
 

Finally i sold the 62 mm pulley yesterday and ordered a 65mm IBF Poland steel pulley today.
I have a 15 mile Autobahn passage near to my house, no speed limit. "i cannot ignore" that :p, especially when i come home late a nigtht (no traffic).
I feel much safer with less boost and a slightly bigger pulley. I have been @ 180 mph a couple of times last year with my SLK32, i sold last year. Don`t want to miss that feeling with the new 32.
Thanks
Steven