Just wondering those here that don't have any kind of access to HPT or other systems. Who is running a AFPR&FMU on stock tune? and for how long? I assume this is what most pre-00 ld9 were doing before hpt?
I spoken to quite a few people, many pre-00 LD9's it seems popular FMU + HPT combo.
We've run it for years on many of our systems, and still do so with very nice results. When engineered by experts, the outcome can be surprisingly good up to about 10 PSI boost. It varies with the model and year, as many late model combos (2004 and up) will need some form of PCM refinement even if one does use an FMU.
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
Quote:
When engineered by experts
Can you explain this more please? The FMU and AFPR have already been engineered for years now. Still at best it is half assed. You have no control over different RPM's for fueling. You are just adding fuel as a whole. Your best being over fuel to make it rich.
FU Tuning
No, I don't agree! When we've done them and released them for the public, the results have been quite optimal. We've sold thousands of turbosystems so equipped. Using your terminology, I suppose one might call ours "full-assed", in that they pass related OEM standards of driveability and trouble-free interaction with engine management. We achieve quite optimal fueling solutions, certainly not "over fuel to make it rich".
By "experts", of course I am referring to myself and my technical staff, whose combined experience in this field exceeds 60 years. In amateur installations, where we have no control of how people might implement their own versions of FMU systems...that is where we've seen problems. Thus, we conclude that our capability is the difference, in that our experts engineer and validate solutions that work well where applicable (we also offer many systems that are electronically tuned, but typically only on MAF-equipped cars).
With FMU, we need no control in RPM for fueling...the stock PCM still controls this quite adequately. Fuel demand as a proportionate function of RPM is largely unchanged when we add boost, so we have little need to amend it. The proportional effect of the FMU adds fuel correctly per various boost pressures, regardless of RPM. I can elaborate on this using dyno comparisons of before and after boosting to illustrate, should you like.
Of course, bear in mind: my example is only about boosted engines. Undoubtedly, optimizing a normally aspirated engine will require more tools.
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
I do not need dyno graphs, but I would like some more info on your FMU systems and how they are different from one a amateur would install.
Let me also clarify my earlier statements. I have used FMU's on Jbody's with good results, but when compared to the options we now have (HPT, MS, PortFueler, and other standalones), to me it is a joke to use a FMU and AFPR by themselves.
FU Tuning
I'd like to make a distinction here first: My intention is to address the OP's question. In bringing up the positive attributes of an FMU-based system, I must stress that I am not proposing it as a cure-all, nor optimal in all cases...each car model and intended usage presents a different case. However, for cars that will respond well to it, it is by far the easiest, most cost-effective, and least complex method available for bolt-on, stock engine type turbosystems up to about 10 PSI of boost.
The important aspect for me is to provide effective counterpoint to the usage of such terminology as "band-aid", "half-assed " and "it is a joke". These are extreme terms that I find to be unfair if implied on a blanket basis across all possible FMU iterations, which appears to be the intent of the usage. If I read you wrong there, John, please clarify.
What makes us primarily different is our complete knowledge of not only all aspects of FMU-related fuel delivery, but also the interaction with existing car systems. As skilled engineers, we inherently have a much better base of knowledge to work from. In the instance of FMU-equipped turbosystems, we would first analyze all the possible variables and determine whether an FMU would get the job done adequately. Amateurs can, at best, only stumble into these regions, for their relative lack of knowledge not only means they may not have sufficient skills to find the answers...in all too many cases, their lack of familiarity with the car's systems means they don't even know the questions!
We'll customize FMU rate of gain (with internal ratio changes, not just air bleed) and injector sizing for each application. We split some hairs there, and carefully adjust a number of variables until we get an acceptable result across all possible load, boost, and RPM variations. Exhaustive dyno, street, and track validation occurs. Where needed, we'll also supply simple electronic mods, such as our Fuel Mapper which conditions MAP signals to prevent DTC's. The average amateur can, at best, only achieve a fraction of what we are capable of. But, of course, if he buys one of our systems, he can achieve the same results as we did...all he has to do is install the customized package we provide, and adjust as shown. No diddling, no fiddling, done right the first time, for good. Our turbosystems so equipped have satisfied many thousands of customers.
Edited 2 time(s). Last edited Saturday, October 17, 2009 10:26 AM
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
Quote:
The important aspect for me is to provide effective counterpoint to the usage of such terminology as "band-aid", "half-assed " and "it is a joke". These are extreme terms that I find to be unfair if implied on a blanket basis across all possible FMU iterations, which appears to be the intent of the usage. If I read you wrong there, John, please clarify.
Bill I'm commented on the usage of a FMU on a Jbody set-up, not any and all applications a FMU can be used for. If using it as the sole fuel delivery I stand by my remarks.
FU Tuning
Thanks you for the information guys
As negative information could potentially mislead possible buyers of our systems (including those we offer for J-body), I just need to address it lest they be mistakenly misinformed.
After all, had thousands of customers to date felt our FMU-equipped TurboSystems were sub-par, one might think it would be common knowledge. Clearly it is not. As such, I can only guess that you've just never had a chance to experience one of our many satisfied J-body installations! Of course, our product for more modern cars (past J-bodies) uses electronic tuning almost exclusively, for such newer cars are not readily served by FMU and injector change alone..
The rule of thumb is that you can basically say anything you want about someone or some product, as long as it's true. The terms "half-assed", "band-aid", and "it is a joke" clearly do not apply to our versions of FMU systems, including those we offer for J-body. It is indeed gentlemanly of you to admit that this is the case. Thank you for the clarification.
==============================
Getting back to the OP: Yes, if you are willing, you can complete your installation with an FMU system for low boost and expect fine results. I can help.
Please share some more detail about your car, such as:
Is engine built or stock?
What octane fuel will you run?
What boost will you run?
What other equipment is on the car?
Edited 3 time(s). Last edited Sunday, October 18, 2009 10:53 PM
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
when you say "j-bodies", bill... you really should say just OHV and ecotec equipped cars. you show zero love for the quad or ld9 powered cars, which incidentally... makes up quite a bit more of this performance community than the ladder. so i do not understand why you guys have never even wanted to try to do a production style 2.4 kit.
john has been doing fmu's and adjustable regulators on LD9 cars. i believe this is why his statement holds more water than your's. you guys are experts, yes... but experts on the engine that john has delt with for so many years?
the OP has an ld9. can you honestly say that without a shadow of a doubt advising him that just FMU and regulator tuning would be sufficient? because if you can i again question why no production LD9 kit has never been produced.
Edited 1 time(s). Last edited Wednesday, October 21, 2009 7:09 AM
I must confess... I feel like a monster!
z yaaaa wrote:
the OP has an ld9. can you honestly say that without a shadow of a doubt advising him that just FMU and regulator tuning would be sufficient? because if you can i again question why no production LD9 kit has never been produced.
I am sure if there was interest Hahn would have made an LD9 kit
Jason
99 Z24 Supercharged
157hp/171tq - NA
190hp/170tq @ 6psi
LG0/LD9 for Life
well i am sure of that as well, but really... there was enough OHV interest? really??
I must confess... I feel like a monster!
z yaaaa wrote:when you say "j-bodies", bill... you really should say just OHV and ecotec equipped cars. you show zero love for the quad or ld9 powered cars, which incidentally... makes up quite a bit more of this performance community than the ladder. so i do not understand why you guys have never even wanted to try to do a production style 2.4 kit.
john has been doing fmu's and adjustable regulators on LD9 cars. i believe this is why his statement holds more water than your's. you guys are experts, yes... but experts on the engine that john has delt with for so many years?
the OP has an ld9. can you honestly say that without a shadow of a doubt advising him that just FMU and regulator tuning would be sufficient? because if you can i again question why no production LD9 kit has never been produced.
I can say it will work well, for our first foray into J-body was indeed LD9, with a car we built and displayed at SEMA in 1998. GM provided the car. It was one of the torquiest, most fun cars I've done in FWD form (if not for its unfortunate habit of chewing up its automatic transmission!). I mean no disrespect to the LD9 folks here, or anywhere, for not bringing that system into production. We attempted to, but inadequate interest shelved the kit...we were not able to ignite sufficient support at the time. I suppose we were a bit ahead of the curve in terms of availability vs. demand...a decade ago, this was a very new market, with very few participants. Nonetheless, a minimal business model could not be achieved. Another important aspect...the group of potential cars was even smaller, for as the automatics would not survive under the additional power (no tuning software available yet), we could only do manual LD9's.
Within a couple of years, GM next involved us in their new, emerging Ecotec program. Again, I mean no disrespect to LD9, but this new engine was indeed the wave of the future, a fact I could readily ascertain once I saw how close it was in construction to the motorcycle engines we've has such success with. I put all our eggs into that basket, and I don't think anyone could condemn me for seeing the great potential. We've put on a great showing on with Ecotec ever since.
Along the way, GM also had a dazzling LN2 car we were provided for prototyping. They blew in my ear well, reminding me that many hundreds of thousands of these cars had been produced. Again, a good business case, what with an available prototype that was getting mucho exposure, and a whole helluva lot of cars to sell to!
In closing, yes...I can honestly say that the OP can achieve a working FMU-based system on his car. If we did it, so can he. I will offer one additional aspect, however...even FMU-based cars can, in some cases, also benefit from the additional detail tweaking an HPT session can bring. Some fine adjustments can be nice, even if one is not depending completely on HPT for the entire conversion to boosted operation. The proportional fueling of the FMU remains a great way to supplement the fact that the stock LD9 computer and programming/calibration were optimized by GM in a normally-aspirated environment. Retaining their intention and stock calibration can provide superbly streetable results, for GM spent no small amount developing that stock calibration and PCM functions.
P.S.: Is an FMU-based system "better" than a conversion to two-bar MAP and HPT? Depends on who's asking. I'd say the ultimate choice resides with the individual, for some folks lean towards the simple and mechanical, while still others lean to the electronic. Different strokes, as they say. In a case where multiple effective solutions exist, no one solution is "ideal" for every enthusiast.
Edited 4 time(s). Last edited Thursday, October 22, 2009 12:46 PM
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
if i could get my brain to actually soak up the digital side of tuning i would prefer that but unfortunately it does not take to well for me
and with my cars being pre-00, i will be using the fmu and adjustable regulator to get me started.
I must confess... I feel like a monster!
If you do it right, you only need one FMU, and no separate regulator. We have such a unit. What is your stock injector size?
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
As an aside to the above, the first 11-second LD9 J-body (Darren Herde) also used an FMU and larger injectors. What a fun car...lightweight, and 11's on a stock LD9 and Isuzu trans!
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
Bill Hahn Jr. wrote:If you do it right, you only need one FMU, and no separate regulator. We have such a unit. What is your stock injector size?
Or you could be like me and have their FMU and AFR in one unit
Stock LD9 injectors are 24lb
Jason
99 Z24 Supercharged
157hp/171tq - NA
190hp/170tq @ 6psi
LG0/LD9 for Life
Indeed. That's precisely what we do as well
With a stock injector size of 24 lb, using our Stage II FMU (moderate rate of gain), we'd run 30 lb injectors, then adjust idle fuel pressure to get fuel trims back to normal. What is base (idle) fuel pressure on the LD9?
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
Someone check me on this, but I believe base fuel pressure is 43-45psi. My base fuel pressure with 37lb injectors and GMSC was 40psi ( but I used HPT )
Jason
99 Z24 Supercharged
157hp/171tq - NA
190hp/170tq @ 6psi
LG0/LD9 for Life
OK. Then, I'd anticipate an idle fuel pressure of about 25 PSI with the stock programming and 30 lb injectors. With our Stage II FMU, which can add about 5-6 PSI fuel pressure per PSI of boost, we would see the following @ 8 PSI boost:
25 + (8 x 6) = 73 PSI
Very manageble, and well within the pressure limits of the injectors and pump. I'd say even another PSI or two of boost could be had. 85 PSI is typically the upper limit for intank pumps...attempts to go any higher will cause their internal pressure relief valve to engage.
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
If you have HPT capability and had the choice to run a FMU would this be even more ideal to run both? (Ideal meaning as far as tuning capabilities)
In some cases, yes. HPT can only really replace an FMU if you are also able to involve a 2-bar MAP system with its accompanying OS.
HPT alone cannot provide proportional fueling per PSI of boost. It can be made to work, but your AFR's at different boost levels will be non-optimal unless the 2-bar system is installed.
So, one can get the job done with FMU and injectors. Adding HPT capability to same (without a 2-bar system) gives more tools to use, but would be an option, not a necessity at low-to-moderate boost levels (up to 10-12 PSI).
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
I am in the process of doing a build with running around 18psi on the m62 the 2.5 bar system has already been done. I am not looking to just get buy on anything I am looking for anything that will make the tune on this car more complete if that makes any sense.
