+20 potential

[kuzman83]

How much boost should i be able to run with a mostly stock 87 T2? Its got the shelby (T1) bottom end and a G head, everything else is stock.

[Clay]

I run 20 psi on an 86 bottom end, which has LW rods. So far, knock on wood, no issues w/ a bit of street time and 2 seasons worth of drag passes.

[iTurbo]

I ran 19-20 psi in my Shelby Lancer for a long time. It was stock '87 TII with 3" exhaust. I had +20s, adjustable fuel pressure regulator at 55 psi base pressure, and an adjustable overboost eliminator. Just make sure you get the highest octane gas you can get (91 or better) and if you go above ~10 psi make sure you have it floored. My engine like to ping if the boost got too high at part throttle.

[kuzman83]

did it make a big difference, stock tranny?

[iTurbo]

I was using an A568 out of a '90 turbo Caravan. The car made a lot more power, but at that boost level I would say the stock intercooler was holding me back. With that much boost, it was impossible to put it down to the ground unless I was in 3rd or 4th gear. I was using a grainger valve for boost control and had to micro-manage the throttle in the lower gears to keep boost at 12 psi or less to manage wheel spin. Not the best for driveability but it was a rocket on the highway.

[kuzman83]

so do you think it would shred my A-520?

[risen]

so do you think it would shred my A-520?

The 520 in my csx is still together and it's seen about a year of 20 psi street abuse. The clutch can't hold the power I'm putting through it, so that's probably saving the tranny some.

[moparzrule]

+1 a 520 is pretty stout. It's OK to about 250 WHP as is, and I was running 300 WHP with a moly plate on the end of one.

With 20 PSI and everything else pretty stock you'll be in the 200-225 WHP range.

[Anonymous_User]

How much boost should i be able to run

Crank it up until a piston cracks, then back it down just a smidge.





What? Seriously, that's how I set my grainger last time. :D

[BadAssPerformance]

so do you think it would shred my A-520?

I made over 100 5000+ RPM launches on slicks before the teeth fell off of 2nd gear in my '87 A520 in my '87 CSX Clone Shadow. Runs ~19psi on the dragstrip, has seen 27psi on the highway... +20 injectors and 100 octane.

[WickedShelby88]

That 520 definitely got some good endurance testing JT. Thats what I plan on running in my shelby charger along with a GLHS stage 2 LM and +20's which will be a similar combo to what you would have.

[moparzrule]

520's live a lot longer with a 2.2 behind them rather than a 2.5, thats what i've found anyway. They don't like the torque.

[iTurbo]

I have awful luck with A520s, behind a 2.2L or 2.5L. I went through three before I gave up and went with the A568. All of them made a low grumbly sound any time the car was moving, especially if it was in gear. I think it was the intermediate shaft bearing but never found out for sure.

[kuzman83]

ok one more dumb question but if i were to put in a g valve and set the boost to 19-20 lbs. does that mean its boosting that much all the time. so like when i'm cruising on the highway its boosting at 20 lbs?

[BadAssPerformance]

It depends, it can change with load. My shadow runs only ~19psi at the dragstrip all thre way thru 4th gear, but on the highway in 5th it has hit 27psi :eek:

[kuzman83]

wait so is this g valve not very accurate?

[kuzman83]

and will i need a 3 bar map sensor

[TurboJerry]

I made over 100 5000+ RPM launches on slicks before the teeth fell off of 2nd gear in my '87 A520 in my '87 CSX Clone Shadow. Runs ~19psi on the dragstrip, has seen 27psi on the highway... +20 injectors and 100 octane.

If there was preload on the input shaft bearings the teeth may have fallen off a little later, but it's going to happen eventually.........

[TurboJerry]

G-valve is accurate, and the stock 2-bar should work fine. You may need a map diode/grainger so it won't boost cut going higher then 13 psi...

[kuzman83]

then why would badassperformance's spike all the way to 27? is it just the way he has it set? and i have a custom cal'd computer with all the overboost stuff disabled if thats what youre referring to.

[TurboJerry]

If you have a computer done up like that, then all is well. The problem is that with the high load in 5th gear, it's very hard to keep it from getting too much boost unless he may have had too big a bleed hole in the grainger...... I only drill a .020" hole, and seems to control spiking well. Not many people have drills that go smaller then .062"

[kuzman83]

so with the overboost settings gone it wont spike? and i was just planning on buying a g valve from fwd perf. do those come predrilled?

[TurboJerry]

Not actually, I mean you won't have boost cut with the settings raised all the way up.

The G-valve from FWD should be ok. I believe they have the correct size hole predrilled....... Pretty much plug and play.

[BadAssPerformance]

My Grainger only has a 0.20" hole...

[kuzman83]

so is this really a good idea for reliabilities sake if theres a chance of it spiking all the way to 27 pounds?

[kuzman83]

is there any way to make sure that doesnt happen ?

[TurboJerry]

I should've known better!!!!

[moparzrule]

Forget the grainger, just get the cheapest manual boost controller you can find on ebay. For like $10 shipped I've been using the same one for years and I don't have to take the vacuum line off everytime I want to adjust it either.

[kuzman83]

I should've known better!!!!

?????

[TurboJerry]

so is this really a good idea for reliabilities sake if theres a chance of it spiking all the way to 27 pounds?

You'll have to try it and see. Maybe loosen the WG arm if it does.......

[moparzrule]

OK they went up in price slightly, but this is the one I use-
http://cgi.ebay.com/ebaymotors/NXS-MANUAL-BOOST-CONTROLLER-300ZX-GSX-GST-STI-RX7-MBC_W0QQcmdZViewItemQQcategoryZ33742QQihZ015QQitem Z250226183761QQrdZ1QQsspagenameZWDVW

[TurboJerry]

?????

Opppppssss, That was meant for BAP!

[kuzman83]

i just bought one its on the way, thanks for the tip

[TurboJerry]

OK they went up in price slightly, but this is the one I use-
http://cgi.ebay.com/ebaymotors/NXS-MANUAL-BOOST-CONTROLLER-300ZX-GSX-GST-STI-RX7-MBC_W0QQcmdZViewItemQQcategoryZ33742QQihZ015QQitem Z250226183761QQrdZ1QQsspagenameZWDVW

Looks good!

[BadAssPerformance]

Opppppssss, That was meant for BAP!

Yeah, the right size bleed hole but I think the turbo has some issues. It makes the 19psi strip / 27psi highway with the grainger spring stretched and knob screwed all the way in. I think if everything was cool with the turbo it should make more boost at the strip. Crazy used Shelby Lancer motor parts! ;)

[contraption22]

I ended up having to switch to an .030 bleed hole because my boost would creep down in top gear, but im running all 1/4"hose.

I use N20 jets as bleed orrifices for accuracy.

[BadAssPerformance]

It doesnt get much more accurate than a jet :thumb:

[TurboJerry]

I ended up having to switch to an .030 bleed hole because my boost would creep down in top gear, but im running all 1/4"hose.

I use N20 jets as bleed orrifices for accuracy.

Those jets are very handy for more then just N2O and Fuel! I don't think the hose Dia. makes that much difference though... Maybe the manifold source has alot of velocity screaming by it causing a delta at the hole where the fitting is?

[89pbody]

i had a grainger from fwd performance on my shadow and it worked perfect.i wish i would have grabbed it off the car before i sold it...... oh well 25 bucks and i can have a new one.

[Subliminal]

I run 14 psi with my +20s....turned down as low as my AFPR will allow...and still a bit rich at times. ;)