opinions please NOS or Big turbo, what do you guys think Options

[zach]

Hey guys,
I was wondering what you guys think about running a big turbo, significant lag, or using a smaller fast spoolin with a healthy shot of n2o.


here is my situation, 1991 automatic talon tsi awd.
If I go with a big turbo, I will need a tall stall speed. but it will pull like mad.
or go with a small turbo and keep it friendlier for around town driving, and use lots of nitrous.

Or. use big ass turbo, and nitrous? in this case... should nitrous just be used for a launch and then cut off when it boost, I could use a more streetable stall this way.

or go for broke and use tall stall big turbo and nitrous all the way down the track?

Also, does anyone know what this engine will take, If I'm gonna run 29 psi, can I still shove a 200 shot down its throat, without blowing the head off the motor?

thanks,

zach

[akamiami]

usually people use nitrous to help spool a larger turbo. they also seem to prefer wet kits. awdnot2gsx has nitrous on his car, as well as KOUIN3 (if that car is on the streets yet).

[natedogg]

Also, does anyone know what this engine will take, If I'm gonna run 29 psi, can I still shove a 200 shot down its throat, without blowing the head off the motor?

A 200 shot on 29 psi may be pushing it...just a bit. A stock 6-bolt is supposedly good for up to 450-500 whp. After that its time for stronger rods and pistons.

[KOU In3]

Well, I'm set up for nitrous but my car isn't even on the street yet so by no means should my input be taken as gospel. But here's what I have to offer you from my reasearch:

Personally, I think the best set-up would be to run a big turbo and only use the nitrous as a spool-up tool. You'd need a good quality wet-kit, a window switch, and the big turbo with supporting mods. But if this is a primarily street driven car you'd be driving around without ever hitting boost most of the time. It'll seem slow unless you were planning on running someone. In which case it would seriously haul. And it would probably be the most 'reliable' way to run both.

Not sure what your budget is and I hate to burst your bubble but I hope you have $10K to play with the way you're talking. You're definately going to need to build that auto tranny up to take the abuse. Complete internals and reworked head if you want 29 psi and a 200 shot. On a 4 cylinder turbo I'd keep it down to a 50shot personally or 100 if you plan on being crazy. Remember guys with big blocks and 8 cylinders are running 200 shots. We've got half the cylinders and 1/3 the displacement. I put the big price tag on it too because of all the supporting mods involved if you are stock now and all the parts that will break very quickly.

I personally don't think a small turbo and lots of nitrous is a cost effective solution. You could go all turbo for less and be faster than a 14B and a safe nitrous shot while still being less prone to going boom. What are your final goals for the project though? Easier to figure out how to build to a specific goal than to just wonder which is doable or 'better'

Oh, and personally I don't plan on using nitrous for the launch. Put in a trans brake and with that and AWD you should be able to launch with boost and pull 1.6's all day long. Ask Daryl about breaking a 4bolt rear with only a 50 shot off the launch. Nitrous is much easier on a drivetrain that's already in motion and revving a bit. Use it from a stop with no revs and things will break... fast.

In my case I'm just hoping to max out the stock engine and internals. I figure a well supported 20G and a 50 shot should be about all I'm willing to risk on a stock rebuild. But I'm a bit of a coward and will probably mainly use the nitrous to chill down my FMIC since I'll be too scared to go boom most of the time.

Well, that my longwinded $0.02 Hope it helps.

[zach]

thanks for the replys.

maybe i should be a little more descriptive on what's in this car.

I have a completely built head, ported polished, oversized valves, ross custom 9:1 pistons, billet aluminum racing rods, the transmission is being overhauled as we speak with a level 10 pts kit, with trans lab shift kit.(they claim bullet proof)
I have a racing intake manifold, 3" mandrel bent exhaust, NOS directport injection(200shot) big ass fmic
alot of the small things, (brakes, pulleys..Etc...etc....)
I'm more or less trying to decide on the turbo, and if I'm gonna use the nitrous or not.
once I figure this part out, then I know what cams to use, what tourque converter, how to build the fuel system... blah blah blah.

any suggestions would be wonderful
thanks,
Zach

[natedogg]

That's a really nice setup. Did you buy the car from someone else? Has the 200 shot of nitrous been used on the car before? I've never heard of anyone short of the likes of Buschur or Glazar using that much nitrous on a DSM. If I were you, I'd keep the nitrous since the car is already setup for it, but I'd rejet it to somewhere between a 50 to 100 shot, depending on what turbo and how much boost you'll be running. What kind of fuel control do you have? AEM EMS? VPC? PMS?

Does your car have a 4-bolt rear-end? I think the 90's and 91's came with the 3-bolt rear-end stock.

[zach]

I bought the car bone stock with a valve whipped engine in it.
I'm building the car myself, hopefully it will be running in a couple of months.

I should have it together by Oct for vicary track rental

the reason I have the nitrous is it was to good of a deal to pass up, it's a brand new direct port. with remote bolttle opener, high flow bottle valve and it's custom painted bottle,(multi color paint like on the mustangs)

I've never heard of anyone juicing that much on a high boost application,

I'm considering going with a br580 turbo, So I should be able to put 560plus at 29psi to the wheels, adding the n20 just might be to much.

any suggestions would be geat?

[zach]

on the fuel control, I'm think about using a karman vortex converter with safc.

I don't know if you've seen the Karman vortex converters, but there is almost no restriction.

I'm gonna try it, if it doesn't get the job done,then i'm gonna probably vpc it.

[KOU In3]

Sounds like you're well on your way to a beast there. I'm not familiar with the karman vortex converters or their price range but I'm cheap and poor so that's no surprise. Have any pics of the build-up in progress for us?

[Mike]

All this talk about your car Zach and Im gettin wood here! you have to show us some pics man!

[natedogg]

Cool! Like I said before, nice setup. I'm not familiar with the karman vortex converter either. I know the stock DSM sensors are karman vortex sensors that output a flow frequency signal based on sonic waves across the sensor chamber. Its a very efficient way to measure airflow, but, as we all know it also creates a restriction for those of us who want to flow more air. Do you have some info on this vortex converter that you can share with us?

[zach]

Karman vortex converters are essentially the same thing as your gm mass translator, but uses voltage instead of frequency. which means you use a mustang mass air. which means you use an aftermarket sensor from pro m wich is your 3" or bigger with a straw that holds the sensor, almost no restriction of air flow,

website is www.pro-flow.com

if you want to see the sensor go to winners circle, check out the shiny one.
the whole setup with airfilter, sensor, translator is around $400, it's adjustable also.

[zach]

I'll shoot some pictures and post them soon, the cars in pieces right now it's not too pretty.

[natedogg]

Ahh...okay...now I know what you're talking about. Its basically the translator for use with the mustang sensor instead of the GM sensor. I've seen some people talk about that unit on talk and tuners. That's cool. Just as a suggestion though, I'd look into the GM MAFT. It sounds like the unit you're talking about has all the same uses and capabilities as the MAFT, but you can pick up the GM MAFT from ramchargers plus a new sensor from gmpartsdirect for about $100 cheaper. You can save even more money by picking up a used GM sensor from a junkyard on the cheap. Again, just something to look into.