How many hp will a Thrasher 92 support?

[Fred 86 GN]

Just trying to get a feel for the maximum injector duty cycle that the chip is programmed with...70%? 80%? 90%?

The race chips are easy -- static = 100%.

The street chips with more boost than 17psi are tricky.

For example:

stock injectors (which I do not have -- this is an example) = 28lb/hr
assume 0.5 BSFC
6 cylinders

(28 x 6) / 0.5 = 336hp at 100% duty cycle. (race chip)
336hp x 0.80 = 269hp at 80% duty cycle. (street chip)

So what is a Thrasher 92 duty cycle based on the experiences of those who have used them and the car weight and 1/4mi mph of their TR's or dyno runs?

Thanks,

 

[Scott231]

All chips for stock injectors (Thrasher or not) are programmed for static duty cycles at WOT. The blue top Thrashers can be had in static or non-static setups. The latter of which runs about 85-90%.

 

[Fred 86 GN]

So then is it safe to assume that all street chips are designed to limit the injector flow rate to 30-31 lb/hr?

stock and green stripes = 28-30 lb/hr = 100%
blue tops = 36 lb/hr = 85% (36 x .085 = 30.6 lb/hr)
009's = 42.5 lb/hr = 72% (42.5 x 0.72 = 30.6 lb/hr)
etc.

So the old saying "you cannot have a chip for both 93 octane gas and 17psi boost and use the same one chip for 110 octane gas and 23psi boost" is true??

Unless a seventh injector is used, or the fuel pressure is turned way up, it seems to be limited by the amount of fuel.

That is what I was wondering about.

 

[ijames]

I don't think it's safe at all to say that all steet chips for all injectors bigger than stock use duty cycles less than 100%. It varies by chipmaker and injector size. Personally, in the chips I've made, up to 50 lb/hr I go static even with 93 octane. You have to crank the fuel pressure down some but that way you can crank it back up if you want to run the boost up with race gas.

 

[Scott231]

Originally posted by Fred 86 GN
So then is it safe to assume that all street chips are designed to limit the injector flow rate to 30-31 lb/hr?

No, that is not a valid assumption at all.

stock and green stripes = 28-30 lb/hr = 100%
blue tops = 36 lb/hr = 85% (36 x .085 = 30.6 lb/hr)
009's = 42.5 lb/hr = 72% (42.5 x 0.72 = 30.6 lb/hr)

All you've done there is prove that these three different injectors can be programmed to run at the same fuel volume level...which is really a Given anyway. The benefit you get from the bigger injectors is that they exceed the max volume of a smaller injector. All injector are run Far, far below static for non-WOT operation at the lower RPM level.

So the old saying "you cannot have a chip for both 93 octane gas and 17psi boost and use the same one chip for 110 octane gas and 23psi boost" is true?

The saying is true if you want the best performance for the given octane level. If a chip works well (no, or minimal, knock) with 110 octane, it will not necessarily work well with 93 octane and the lower boost (although it might). It is entirely dependent on your setup.

Unless a seventh injector is used, or the fuel pressure is turned way up, it seems to be limited by the amount of fuel.

There are several limitations to maximum HP, fuel volume is only one of them. Engine's are nothing but air pumps (gasoline is only the catalyst to ignite the air). Accordingly, if you can't flow an adequate volume of air - you will not make a relative amount of HP.

 

[bruce]

Originally posted by Fred 86 GN
Just trying to get a feel for the maximum injector duty cycle that the chip is programmed with...70%? 80%? 90%?

The race chips are easy -- static = 100%.

NO

Running static is just due to having too small of injector, and is a miserable way of trying to patch things together to work.

There are several million posts here with folks trying to get their cars to run. Survey how many are about folks with smaller then 50#ers, and those above, and who's having fits.

Get a decent set of properly sized injectors and a good chip.

Those sizing numbers yuo quote are nonesense, when applied to an oem ecm. If you want to double the HP of you car double the injector size. Those formulas all ignore the close loop logic of a stock ecm.

The trick is having things tunable, either learn how to do chips, or get a Translator plus so you can tune your car.

 

[TurboDave]

Re: Re: How many hp will a Thrasher 92 support?

Originally posted by bruce


NO

Running static is just due to having too small of injector, and is a miserable way of trying to patch things together to work.

There are several million posts here with folks trying to get their cars to run. Survey how many are about folks with smaller then 50#ers, and those above, and who's having fits.

Get a decent set of properly sized injectors and a good chip.

Those sizing numbers yuo quote are nonesense, when applied to an oem ecm. If you want to double the HP of you car double the injector size. Those formulas all ignore the close loop logic of a stock ecm.

The trick is having things tunable, either learn how to do chips, or get a Translator plus so you can tune your car.

Hmmm, a voice of reason here in the dark, nether world of injectors.

If I had my druthers, I'd never run an injector sized such that I had to drive it static to gain my goals. 80%-85% duty cycle has been quoted by many injector experts and manufacturers alike as being the ideal duty cycle to strive for at your chosen level of WOT performance. Once you drive the injector static, you have just lost any control you have over it. Even though the system will attempt to drive injectors beyond the 100% point, once there, 100% is a 100%, nothing more can be achieved, unless you like fiddling and guessing with upping the fuel pressure.
But if that's the case you might as well dump your ECM and go back to the days of carburators.
The reason for ECM's and other fuel managements systems is to gain positive control of fuel delivery. Why go backwards in technology?

Get the injectors sized so that your run down the track doesn't run them beyond the 90% duty cycle point and you'll have the control you need.

I think Bruce and I are probably on the same page here.

 

[bruce]

Re: Re: Re: How many hp will a Thrasher 92 support?

Originally posted by TurboDave



I think Bruce and I are probably on the same page here.

Yes.
I've got 55s, and run about 85% DC at WOT.
idles at 675 in gear.

 

[Fred 86 GN]

"No Fred!" "Bad Fred!"

Wow, lots of negative feedback. I threw some numbers out to get the discussion into numbers and away from the typical "buy different parts" and "you need to tune it better" replies.

My posted "nonsense" came straight from experience with my 86GN, DirectScan software, analysis of the injector pulsewidth shown by DS from different chips, discussions with Red Armstrong and Joe Lubrant, and some compiled data I received at the 1998 GS Nats tech session.

I don't have a bench ECM. I have not programmed chips. But I can look at data from one chip and compare it to another to see the differences. I can make calculations to estimate what hp I am making and what the potential hp should be. Primitive, but it makes me feel better doing a few cross-checks to see if I am tuning properly.

if 80-85% is the best injector duty cycle value, which I agree is probably true since static is somewhat out of control, then how come I have seen listed on this board and quoted by fellow TR owners the following 1/4-mile numbers:

114mph on stock injectors in full wt. car = 430hp
using this fuel flow to hp calcuation --
flow x # of cyl. / BSFC = hp
solve for flow --
Flow = BSFC x hp / # of cyl.
Flow = 0.5 x 430 / 6 = 35.8 lb/hr
That is 20% more fuel than stock injectors can flow

118mph with blue tops in full wt. car = 470hp
Flow reqd = 0.5 x 470 / 6 = 39.1 lb/hr
That is 10% more than blue tops can flow

So instead of running 85% of duty cycle, these folks run 100% and jack the fuel pressure way up to make the power?

Should I only expect to see 430hp out of my 009's at 85%?
That would max out a 3600 lb car and driver at 11.8 at 115mph.

Who are these amazing tuners that run high tens/low elevens with 009 injectors at 120+mph and how do they do it?

 

[galoush]

street chips and racegas & hi boost

Fred on my last trip to the track i ran my RA 93 street chip with V.P c-16 race gas (117 octane) up to 27 psi. with my sig setup and had no knock or problems , im also using a big paxton pump through AN8 lines . dont know if that has a factor if any though. I just got Reds 100 chip with 26deg of timming , ill try that soon . I belive the street chip gives it 20 or 21 deg.

 

[Scott231]

Re: "No Fred!" "Bad Fred!"

Originally posted by Fred 86 GN
My posted "nonsense" came straight from experience with my 86GN, DirectScan software, analysis of the injector pulsewidth shown by DS from different chips, discussions with Red Armstrong and Joe Lubrant,

Not sure exactly which numbers were referred to as nonsense, but remember, you're not racing a calculator. Nor should you expect to see a constant duty-cycle being used as the car goes down the track. Just because you can make X#HP on a dyno (for example) doesn't mean you can make that much HP all the time on the dragstrip.

if 80-85% is the best injector duty cycle value, which I agree is probably true since static is somewhat out of control, then how come I have seen listed on this board and quoted by fellow TR owners the following 1/4-mile numbers:

114mph on stock injectors in full wt. car = 430hp
using this fuel flow to hp calcuation --
flow x # of cyl. / BSFC = hp
solve for flow --
Flow = BSFC x hp / # of cyl.
Flow = 0.5 x 430 / 6 = 35.8 lb/hr
That is 20% more fuel than stock injectors can flow

Stock injectors are rated at ~28pph at 45psi static fuel pressure. The above example does not state the static fuel pressure used, the boost pressure, how cool that boosted air is, etc., etc. There is more to going fast than calculated numbers.

So instead of running 85% of duty cycle, these folks run 100% and jack the fuel pressure way up to make the power?

That is likely with a heavy TR. Note: "full weight car" is not defined above.

Should I only expect to see 430hp out of my 009's at 85%? That would max out a 3600 lb car and driver at 11.8 at 115mph.?

You are assuming ETs are a direct function of mph...that's not the case. Sixty foot times have a huge effect on ET with Turbo Regals.

Who are these amazing tuners that run high tens/low elevens with 009 injectors at 120+mph and how do they do it?

Tim Stockwell was one. He admitted to over 30psi of boost (if my memory serves me correct) and lots of fuel pressure.