Just wondering guys,

Would it be possible to boost low, say 8.5 psi at max and 6 psi daily, on a stock ITR motor without reducing the CR from 11to1?

I always thought that 11 to 1 CR would not handle boost at all...

 

I'm gonna go with no.....I'd say go forged 9.8:1 pistons and eagle rods that's probably the highest compression your gonna wanna run

 

its all about tuning

 

I had 11.1:1 cr
I have Haltech e6k standalone + 440cc injectors
I had JRSC boosting 8-9psi

............after running 0.5 hours on the dyno (with wide band O2 sensor) it goeas BOOOOOM. Zyl. # 4 no compression.

Perhaps with turbo it is possible to boost 8psi, cause the intake temp is waayyyy cooler than with the SC.

 

I'm running it right now, but I wouldn't be if I didn't have it tuned right.
We have 94 octane in michigan, which I don't take for granted anymore
after hearing about 91 only in CA. After seeing my a/f curve with the wideband
I'm not worried about it.(well maybe just a little)

but you could get a thicker headgasket and put it in for less than $100

steve

 

do u think a thicker gasket is good enough? or save up for some low CR pistons are the only way to go?

I wanna turbo my JDM R but I dun wanna blow the motor...

 

Tuning is the key. I would at least go with Hondata, AEM, Haltech, or any other standalone if you are sticking to that comp ratio. I would also suggest using water injection on top of the intercooler for even more added protection against detonation. I personally use the spearco kit and love it, and i paid 210.00 shipped for it. Added bonus of that comp ratio is the responsiveness of the throttle when off the turbo, and the faster spool up times as well. Overall, high comp ratio does limit the tuning window, but when you do tune them right the benefits are greater than low compression, although you are limited to how much you can boost (generally no higher than 15psi on race gas).

 

Well I only paln on boosting about 6 to 8 at max, but what I really want is to have a reliable engine which wont blowa fter one year...

 

not true... once again it has to do with tuning

 

Like everyone else said......how good is your tuner....?!
because if hes not on top of things you will need a rebuild or new motor very soon.

 

hey (austrian ITR)

did the haltech have the map sensor on the intake manifold ?
If so did it have separate fuel/ignition curves for different boost ?
do you have your a/f ratio for the dyno where #4 zyn blew ?

I'll do a compression check soon. after I get the datalog posted

 

Yes the GM 2 Bar Map sensor is located to see boost and vacuum. The Haltech has seperate fuel/ignition curves boost dependend. We always had a a/f ratio of 0,85 (which is about 12,5 I think) We in Europe are using the Lambda ratio (Lamda 1 is equal to 14.7:1).

The dyno has no datalogging for the a/f mix, but the digital Lambda-meter does´nt go over 0,85. MY tuner told me that he can only run very low timing and the a/f is a bit richer (to cool down the combustion camber) than in the sessions with 5.5 psi boost. .......he warned me, that my motor will not last long, but I said lets give em a try

The worst thing of the JRSC is that the compressed air is more than 80 degrees Celsius hot, while the air of an intercooled turbo is only about 35 C.


[Modified by austrian ITR, 12:26 AM 1/30/2002]