I'm looking into possibly buying a turbo kit from BBSDesigns, but have a couple questions.

1) Supposedly, it is safe to run a turbo on a stock engine, with stock ECM and stock injectors up to 5psi (turbo I'd be using is Turbonetics 62-1). I read somewhere on the boards, that 5psi will add roughly 1.3 times your current hp. So my ~225hp car would put out around 292hp. How much boost would be necessary to be right around 400hp?

2) Up to 5psi is said to be safe on a stock engine. If i go w/ higher psi to get to 400hp, what engine internals would I have to change to safely maintain the psi needed to produce 400hp? (my engine = 350 TPI, 49,000 miles)

3)Along with upgrading engine internals, I'd need bigger injectors, and a reprogramming on my ECM, right? Would I also need a higher flow fuel pump? Anything else?

I'm bidding on "Turbochargers," by Hugh MacInnes so I'm sure I'll get all my questions answered with that book, but I was just wondering about those few things. Short answers are fine, I don't need in-depth responses about how everything works (although I wouldn't mind that) since I'm getting the book soon, but I'd just like to know what all I'd be looking at upgrading.

Thanks for any info

 

How about starting with getting that sig pic down to something close to the rules laid out by the sticky at the top of each forum, 400x100…

Usually it’s closer to 1.2-1.25, but OTOH, a typical L98 is putting over it’s advertised hp to the wheels, so it’s making more then the rated 225 (or 230 or 245 depending on the year).

Assuming you’re actually making 225, and assuming that you’re running a decent intercooler you’re probably looking for something in the range of 12psi.

400hp isn’t the problem, you could do that with the stock shortblock if you can control detonation at that boost.

400hp, think 36pph injectors and at least a 190l/h pump.

 

so 12 psi/intercooled should get me to 400hp? and that can be done with the stock internals? hmm

 

As Mark said, controlling detonation will do wonders at making a boosted engine live. Eliminate detonation and make sure the air/fuel ratio is spot on, and you should do quite well on a stock long block. Of course better heads would get you to your 400hp goal quicker. And if I had to pick the weakest link in the stock L98 for running boost, it would be the cast pistons.

BTW, my TT IROC put 328hp and 468ft lbs to the wheels with a bone stock, 95k mile L98. This was with 7psi intercooled. Another 5psi should get you to 400 at the crankshaft.

 

Keeping the RPM down and avoiding detonation helps a lot.

We put 10 psi intercooled boost into a stock 1987 IROC 350 TPI.
The only thing done to the engine is larger injectors.
We have the rev limiter set at 5500 RPM and shift at 5250 according to the stock tach.

The rear axle is stock with 2.73:1.
The tranny is a th400 with 2.48:1 on first gear. ( The stock th700r4 has 3.06:1 on first gear )

This is a G-Tech measurement we did yesterday.

1) 0-60 mph = 4.73 sec, 1/4 mile = 12.87 sec and 118.1 mph
2) 0-60 mph = 4.55 sec, 1/4 mile = 12.73 sec and 118.4 mph
3) 0-60 mph = 4.49 sec, 1/4 mile = 12.70 sec and 117.8 mph

We also did two hp runs with an estimate weight of 3970 lbs. The weight was probably more becase I am about 270 lbs and the driver is about 200 lbs. It was about 2 gallons from a full tank of gas. We were both in the car for the 1/4 mile and hp runs.

The first run was 350 rwhp and the second 355 rwhp.

With 18% transission losses this would indicate 420+ hp at the crank.

As I said these are G-Tech pro numbers so they are not exact, but they are an indication.

 

The problem with the g-tech pro times is that they aren’t really useful to compare to anything but other g-tech pro times. You don’t happen to have any runs from before the turbo setup?

If anything, I would say that with the TH400, 18% drivetrain loss is on the conservative side…

 

Yes, I know that G-Tech is not the real thing.

We are in the process of building a better performance measuring tool for it. We will put 10 magnets on the front wheel and use a hall effect sensor to measure the magnetic pulses. That will get a resolution of about 8" on the road. It is easy to calibrate by counting the number of pulses on a known distance.

By using the audio input and recording a WAV file the pulse frequency can be analysed. With a 44.1kHz sample frequency the time axle is known. This will be as exact as a real track to measure quarter mile trap speed and ET. You can also get 0-60 mhp time and distance, and any other measurement you want.

I already have the software ( I made it three years ago ).
I recorded the VSS signal and that works too. The major problem is wheel spin. That will affect the distance measutred. With magnets on the front wheel that problem is eliminated, and I also get better resolution.