TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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Hi all, We have received questions regarding the mod affecting the spray pattern. The answer is NO, it does not affect it at all. Check out the pic. I am having a little trouble posting the live video, but hopefully the picture will help for now.
As far as the injector touching the manifold and transferring heat , Think about this there isn't a car made with fuel injection today that the Fuel Rail isn,t bolted to the intake or Cyl head metal to metal without heat transfer thru the bolts and rail, when you turn the engine off it will absorb heat, will it boil the fuel out I doubt it. When you turn the ign on what happens the fuel system pumps up to desired fuel pressure so when the Engine starts it does not have a hard time starting .
hi irocuroc , i was excited with Southbay's mod,its something new to the TPI crowd
but now with your post im very concerned about trying this.
what you think ?
You should be excited about this Calderone, we worked really hard on this. For the longest time all we heard is that the bosch lll's are short, the bosch lll's leak because they do not fit correctly into the rail, who has the longest bosch injectors, who doesn't, who is milling to make the injectors fit, additional orings, spacers, well,,,,here is the answer...."plug n play". We tested these things for 6 months on local cars and our own cars and heat transfer was not an issue. We have sold about 30 sets already and have not received one complaint about a hard start or anything else for that matter. IF and when a problem arises, we will be sure to deal with it!!!!!
In the meantime, take a look at the pic of our injector with the new mod, and the pic of a stock bosch ev14. They both have a similar "metal" piece and an oring on the bottom!!!!!!!!
By the way, this mod is available for any size bosch design lll fuel injector! We will be listing them on our website within the next couple of weeks, we will keep everyone posted!!
Last edited by southbay08; 11-19-2009 at 10:43 PM.
if heat is a problem for injectors on a L98, it would be a problem on the newer vehicles with the plastic manifolds too.
all new cars run at least 200 degrees. and just like the L98, few turn the cooling fans on below 230 degrees. so you still have the same under hood temps. true a plastic intake doesn't pull heat out of the motor like aluminum does, but the under hood temps are still very high, especially after a hot shut down.
the last car i put a set of the modded bosch 3s in was a few months back, it was a 91 vette. the owner drives it most every day now and has no problems with driveablity or hard starting when hot, cold or at any other time.
the bosch 3s work, even on an aluminum intake in hot houston summers.
heat isn't why the manufacturers went to plastic intakes, its the price of manufacturing the part and the weight savings over aluminum.
the first plastic intakes had a lot of problems with cracks and warping, and its still a problem now.
if you had an aluminum that was cracked or warped, odds are it could be repaired and will last just fine. if you have a plastic intake thats cracked or warped, it can only be replaced.
manufacturing price is also the main reason they use plastic on injectors now instead of metal.
what modded injectors did you use? Where did you get them? we are talking about this new one that just came out from Southbay last week. So how did you get them a few months ago. I guess you did not read the bosch website on heat. If you think heat is not an issue, then you know nothing about the subject.
what modded injectors did you use? Where did you get them? we are talking about this new one that just came out from Southbay last week. .
Don't know if there is any difference with these injectors but another vendor has been supplying Bosch III 's for over a year now; plug and play with amazing feedback from happy TPI and LT1 owners
I recently purchased a set of the reman Bosch III from south bay fuel injectors. The injectors have the spacer installed on them and I have had absolutely no problems. The injectors have made a huge difference in throttle response in my 91 Z.
I am not understanding why that some of you think that heat transfer within the injectors is going to be such a big problem. Sure, I understand that the coil, within the injector is subject to breaking down under extreme heat. But, I don't understand why that you think the spacer on the injector is going to place extra heat on the coil. The coil within the injector is not located near the metal spacer. Also, before the coil could break down it would have to be subjected to temperatures at or above the temperature of the manifold. That is why that when engineers design new injectors they place the coil within the injector as far away form the surface of the intake that they can. This is why that the original injectors were so bad to malfunction. The heat from the plenum surrounded the injector. The originals could not stand the heat.
The o-rings on any injectors are not designed to be a heat dissipating device. They are there for the same reason as any other o-ring on an injector, to seal off the fuel.
So many people think that heat is the only killer of an injector. Many times it is the residual magnetism from the coil being energized and de-energized. All that an injector is an electromagnet. When the injector is energized an electromagnet moves a plunger that opens a valve. When this valve opens it allows fuel to be sprayed into the intake valve and into the combustion chamber. Over time the injector starts to be up residual magnetism. When this happens the injector does not open and close the valve as quickly as it once did. Therefore the fuel is not entering the combustion chamber at the correct time. Creating a "miss" in the engine.
Also, the spacers are in no way an obstruction to the spray pattern leaving the injector. If you will take a close look at the picture of the spray pattern, you will see exactly what that I mean.
Hope that this helps.
Regarding the heat issue, are not the o-rings of the injector the only thing that touches any metal. If so there should be minimal heat transfer by that method. The only way other way would be from ambient air temperature. So I don't know how much of an issue it is.
OK, so the fact that I still have the org injectors on my 87 GTA w/5.7 TPI with 125 000km's is lucky then?! Although there is a slight engine shake at idle, in park and at very low speeds and rpm's.
Q. So does this sound like to you guys that it maybe time to replace injectors, eventhough I did a OHM test to all injectors, which read 16.00ohms for ALL 8 injectors this past summer?
Thankx, Paul.
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No Mods to speak of....Yet!
Last edited by y84pauloflondon; 11-21-2009 at 12:49 PM.
irocuroc, the injectors i used on the vette came from FIC.
the fuel trims on it are good, 130~132.
i also have a set for my car that came from FIC, i just haven't had the time to put them in yet.
if i had known sooner about this mod from southbay, i might have bought mine from him. there is a good possibility that when i build my 383, its injectors will come from southbay because i like this mod of his.
as has been said, the injector should never physically touch the intake. the O-rings insulate it from the intake. but the O-rings do break down and can allow the injector to make contact with the intake.
i've replaced multec injectors that had a short to the injector body and was popping the injector power fuse because the O-rings were breaking down.
on the MPFI conversion for the 96~02 vortec, the injectors are buried inside the intake, and they are mounted in aluminum. talk about an issue with heat soak after shut down, but yet those injectors work just fine. i have some customers with well over 200,000 miles on them without a problem.
with the motor running at operating temp, my aluminum TPI intake isn't that hot, around 140~150 degrees at idle. the inside of my car gets hotter than that sitting in the parking lot with the windows up during the summer.
excessive heat can be a problem with anything electronic.
but the fact is, any fuel injector should be able to handle 260~280 degrees without a problem.
it isn't so much the heat from contact with the intake that heats up the injectors, its the radiant heat coming off the motor.
then there is direct injection, where the fuel is injected right into the combustion chamber. the injectors are exposed to very high pressures and temps, but they survive just fine. which i find amazing given the fact that
a combustion chamber is such a hostile environment.
dirt is by far the worst problem for injectors.
with a little bit of trash in the fuel system, you find injectors with poor spray patterns, leaking, or with low flow. all of which cause problems.
pauloflondon, i am surprised you didn't find any with low ohms.
of the set i have in my car, 5 are below 14 ohms. 2 of those are below 10 with the lowest around 8.
you could send them in and get them cleaned, but i feel it isn't worth the price because the factory multecs are so problem prone.
pauloflondon, i am surprised you didn't find any with low ohms.
of the set i have in my car, 5 are below 14 ohms. 2 of those are below 10 with the lowest around 8.
you could send them in and get them cleaned, but i feel it isn't worth the price because the factory multecs are so problem prone.
Yeah tell me about it! I was really expecting something like 12.5, 10, 14, 16, and 16.5ohms, just a wide range of #'s, like I've seen others have!!! But nope not mine, and not even a 0.5ohm difference!!!
As for cleaning them I used too run Sunoco 94 Ultra for 10 yrs, and I always used injector cleaner at the begining of the driving season and at the end! SO they Sould be clean!!!! Right, maybe???lol
They should be clean, but the injector cleaner will only do so much. It will not remove any carbon buildup inside the injector and you do not know if there is any residual dirt or gunk, the only way to really clean them is to have it done professionally. Put the injectors through the whole cleaning process,,,, leak test, ohm, spray pattern,, pulse and static cycles, etc.
