mitchberry

iTrader: (1)

hey guys,

Let's see how much flack i get about this question.

i -happen- to have a 10psi turbo sitting around..

I had it on my hayabusa for a while, but when summer came around, i pulled it off so i could ride the bike under normal conditions. there was no reason to have a 350hp street bike.

so, i have the turbo, the gauges, tons of tubing, etc etc,

so.. keep 3 things in mind.

1. the turbo stuff is sitting in my garage in a box on a shelf collecting dust and cob webs
2. my 91 RS LO3 TBI is slowwwwwww and has a nut shriveling 170hp.
3. I literally won't have to spend more than 50 to 150 dollars on the crap i'd need to have a COMPLETE turbo system.. and.. i weld, bend pipe, fabricate, bondo, paint, wrench, etc myself, so there is no problem building it OR a plenum to hook up to the TBI.

I hate that i have to justify this... but if i don't i wont get good answers lol. the last time i tried to post this, some guy said "god save you" as his answer, and that's about all i got before i deleted the thread.

anyway, the motor on the car is -stock-.

and given that, i have a few questions.


1. what is the MAX boost i can add before having to upgrade injectors or re-tune the car. [i'm not afraid of re-tuning, i'm just trying to do this in stages, on the cheap.. if it's 2psi, then fine.. i'll adjust the BOV and dump to 2psi, i just need to know for sure]

2. what is the MAX boost a stock LO3 TBI can hold (usually) without blowing a head/intake gasket? [i'll take that number and remove 25% and assume the gaskets are all rotted to hell on mine... actually, that's not true, it has a brand new intake gasket, but it was installed before i got the car by a non reputable back yard mechanic, so i'm going to yank it off and re-do it]

3. how much power would 10psi of boost through the top of the motor produce? [i know that in the grand scheme of things, 10psi is a SMALL turbo, hence why i had it on my bike... and i'm not expecting it to be a 500hp gain.. i'm realistic, just looking for approximate 'ideal situation' numbers and GUESTIMATES... 5hp? 20hp 100hp?

I'm sure i'll have more questions when you guys answer.

thanks!

Drac0nic

Wrong thread.

ZZ3Astro

1. You'll need to add more fuel somehow. Normally the cheap way to do this is with an FMU. On TBI however, just running a boost referenced regulator instead of the stock one might be enough. Someone around here that has done a boosted TBI setup can give you better input on this.

2. As much as it will handle until it blows! Using FMU/Boost Referenced Regulator, no intercooler and some kind of timing retard maybe 6 or 7 psi. Doing it the right way with a good pump, larger/extra injectors, intercooler, properly handling fuel and spark management it would take 14-18 psi no problem. Can't say the same thing for the transmission though!

3. With my stock TPI turbo combo, I saw 85% efficiency of crank horsepower to boost. Horsepower increase is 6.8% per PSI at 100% efficiency. Using my 85% efficiency as an example, 10 psi is good for a 68% increase X 85% efficience = 58% increase. About 260 crank hp and 400 ft lbs for a stock L03. Again, this assumes you're doing it the right way with a wide band O2 and full control over the fueling and spark, intercooled and all supporting mods.

What turbo is that? Looks like a Garrett GT2554 is popular on Busas making that kind of boost. If so, it's good for about 230 rwhp or aboiut 280 crank hp. Not sure how well it would deal with 5 liters though!

junkcltr

iTrader: (1)

You can turbo it but you need bigger injectors.

What size injectors did you put in the busa?
What computer/ECU/ECM did you use to tune the busa?
What MAP sensor did you use to tune the busa?

Aaron_SK

iTrader: (1)

What the eff is a 'psi turbo'?

junkcltr

iTrader: (1)

It should be in the 60-80 range

83 Crossfire TA

iTrader: (2)

A turbo that makes X psi on one engine will not necessary make that same boost on another engine. It's about airflow and where you end up on the compressor map at the current airflow.

Whether it will work depends on what turbo it is. I have a friend running a GT35 on his busa, that would probably work well on an L03, something like a GT25 will likely be small... it would move enough air to make more power but such a small turbo would be too responsive and possibly too restrictive. You can end up with a setup that is aways either on or off, no middle ground, making it hard to drive at a steady speed and a PITA on the road.

The general idea of turbocharging a TBI car- there is no problem with that, there are even some advantages over TPI, but I don't know of anyone that has done it well.