The CFI Conspiracy Theory
12-09-2012, 09:28 PM
#1
Racer
Thread Starter
The CFI Conspiracy Theory
Found this while searching the WEB for information on the L83 engine. Thought it very interesting and posted for your review. Constructive comments are welcomed (I am not the original author of this piece of work or theory).
The Cross-Fire System is much ridiculed for being a weak performer. This is not entirely true since it has more Hp than all standard option engines in the previous year’s Corvettes. The L83 Cross-Fire Injection was the only engine available that year so it can't be compared with high performance optional engines.
The standard L48 engine had the following ratings by year:
74/195hp
75/165hp
76/180hp
77/180hp
78/185hp
79/185hp
80/190hp
81/190hp
These account for the most Corvettes produced in these years so the 205 Hp L83 Cross-Fire Injection engine has more horsepower than the most C3 Corvettes on the road.
The problem, however, is that the Cross-Fire Injection system has tremendous low end torque, but almost no high end HP. There is however a reason for all this. The Cross-Fire Injection system was originally designed for the LU5 305 cid engine for the F-Body cars. GM expected that the demand for 350 cid engines would drop when emissions laws became more demanding. When the 350 cid L83 was introduced they put the Cross-Fire Injection system on it. Also the manifold has a very poor runner design. The runners are very small at the cylinder heads (almost 2/3 of what normal runners are) to increase the torque. The L98 TPI (Tuned Port Injection) engine was however also designed for a 305 cid engine. There is NO difference between the TPI manifolds on the F-Body cars and the Corvette. This is the reason why the TPI also runs out of breath on high rpm's in the 350 L98. If you've ever driven a stock L98 you may have noticed that the engine sounds like an over-full vacuum cleaner on steroids at higher rpms.
There is a sort of sabotage/conspiracy theory about the Cross-Fire manifold's runner design.
Because the L98 Tuned Port Injection engine wasn't production ready the L83 Cross-Fire Injection engine was installed as an intermediate between the "old" carbureted engines and the "new" multi point fuel injection engine, the L98 with Tuned Port Injection. Probably the initial manifold wasn't so poorly designed and had larger runners and put out tremendous torque and Hp. More than the new L98 (that has only about 25 Hp more than the "sabotaged" Cross-Fire) that couldn't go on like
that, after the oil crisis and the constant decrease in Hp the buyers
wanted more Hp and the L98 was supposed to bring this. A stronger performing L83 wouldn't fit in this scheme and was sabotaged to make the L98 look more glorious.
The sabotaging was done very professional. The manufacturer casted the manifold so (with an indentation in the runner bottom at the cylinder head) that a handy do-it-yourself-port matcher couldn't open the runners up and obtain a strong performing system. As lousy as the craftsmanship is in the casting of the manifold, that good is done the act of sabotaging the stuff.
There is even more circumstantial evidence for this. The CFI system is a weak performer but is a direct descendant of the cross ram system found on the highest performing Chrysler/dodge production engine. The crossram layout is in fact a very good design that combines tremendous low end torque with good high end Hp and street ability.
This all is just theory but in a way it does make sense.
This all does by no means mean that the Cross-Fire Injection system is a better system than the Tuned Port Injection system. The TPI system is a more sophisticated dry induction system (meaning that the air flows dry through the intake manifold and fuel is added just before the cylinder intake ports by an injector. This means all multipoint injection systems are dry induction systems) the Cross-Fire Injection system is, like carburetion, a wet induction system. These systems have problems with fuel puddles in the manifold and this is part of the reason they have a more loopy idle. Also multipoint systems have better drivability and throttle response due to the better controllable flow of fuel to a particular cylinder.
The Cross-Fire System is much ridiculed for being a weak performer. This is not entirely true since it has more Hp than all standard option engines in the previous year’s Corvettes. The L83 Cross-Fire Injection was the only engine available that year so it can't be compared with high performance optional engines.
The standard L48 engine had the following ratings by year:
74/195hp
75/165hp
76/180hp
77/180hp
78/185hp
79/185hp
80/190hp
81/190hp
These account for the most Corvettes produced in these years so the 205 Hp L83 Cross-Fire Injection engine has more horsepower than the most C3 Corvettes on the road.
The problem, however, is that the Cross-Fire Injection system has tremendous low end torque, but almost no high end HP. There is however a reason for all this. The Cross-Fire Injection system was originally designed for the LU5 305 cid engine for the F-Body cars. GM expected that the demand for 350 cid engines would drop when emissions laws became more demanding. When the 350 cid L83 was introduced they put the Cross-Fire Injection system on it. Also the manifold has a very poor runner design. The runners are very small at the cylinder heads (almost 2/3 of what normal runners are) to increase the torque. The L98 TPI (Tuned Port Injection) engine was however also designed for a 305 cid engine. There is NO difference between the TPI manifolds on the F-Body cars and the Corvette. This is the reason why the TPI also runs out of breath on high rpm's in the 350 L98. If you've ever driven a stock L98 you may have noticed that the engine sounds like an over-full vacuum cleaner on steroids at higher rpms.
There is a sort of sabotage/conspiracy theory about the Cross-Fire manifold's runner design.
Because the L98 Tuned Port Injection engine wasn't production ready the L83 Cross-Fire Injection engine was installed as an intermediate between the "old" carbureted engines and the "new" multi point fuel injection engine, the L98 with Tuned Port Injection. Probably the initial manifold wasn't so poorly designed and had larger runners and put out tremendous torque and Hp. More than the new L98 (that has only about 25 Hp more than the "sabotaged" Cross-Fire) that couldn't go on like
that, after the oil crisis and the constant decrease in Hp the buyers
wanted more Hp and the L98 was supposed to bring this. A stronger performing L83 wouldn't fit in this scheme and was sabotaged to make the L98 look more glorious.
The sabotaging was done very professional. The manufacturer casted the manifold so (with an indentation in the runner bottom at the cylinder head) that a handy do-it-yourself-port matcher couldn't open the runners up and obtain a strong performing system. As lousy as the craftsmanship is in the casting of the manifold, that good is done the act of sabotaging the stuff.
There is even more circumstantial evidence for this. The CFI system is a weak performer but is a direct descendant of the cross ram system found on the highest performing Chrysler/dodge production engine. The crossram layout is in fact a very good design that combines tremendous low end torque with good high end Hp and street ability.
This all is just theory but in a way it does make sense.
This all does by no means mean that the Cross-Fire Injection system is a better system than the Tuned Port Injection system. The TPI system is a more sophisticated dry induction system (meaning that the air flows dry through the intake manifold and fuel is added just before the cylinder intake ports by an injector. This means all multipoint injection systems are dry induction systems) the Cross-Fire Injection system is, like carburetion, a wet induction system. These systems have problems with fuel puddles in the manifold and this is part of the reason they have a more loopy idle. Also multipoint systems have better drivability and throttle response due to the better controllable flow of fuel to a particular cylinder.
12-09-2012, 09:58 PM
#2
Safety Car
12-09-2012, 10:05 PM
#3
Racer
Thread Starter
I am well aware of DCS and the Renegade, but my dealings with the company are very disappointing. I ordered a TPS harness from them on November 5th and paid for it through PayPal. They confirmed my order and accepted payment the same day, but I have not received my TPS harness as of this date. I have called them over 3X with no response and emailed them 2X with the following response: (paraphrased) We are back from Thanksgiving holiday and will process your order immediately. I have heard, nor seen anything since. My 3rd email was sent Saturday and no response. I only spent $35 with shipping and handling (and may have recovery options through PayPal) which I plan on exercising next week if I do not receive my order. You will spend much more for the un-proven Renegade through a company with lousy customer service, so beware!
Last edited by scorpion18z; 12-09-2012 at 10:23 PM. Reason: Updated
12-10-2012, 06:19 AM
#4
Advanced
Its a shame that DCS has gone down to that point. I purchased some of their products some years back and their customer service was acceptable and their products were top notch. They have some great products, its a shame their customer services is holding them back. I think its a one or two man operation which may be part of the problem.
12-10-2012, 08:19 AM
#5
only one man now, and he's only doing it part time while working a day job
btw, thats a DCS statement , not mine
op may want to check out the super ram
btw, thats a DCS statement , not mine
op may want to check out the super ram
Last edited by oldalaskaman; 12-10-2012 at 08:33 AM.
12-10-2012, 08:51 AM
#6
Racer
Thread Starter
That is too bad, I was hoping for more from them. The Renegade project seemed like a viable option, especially after reading the conspiracy theory article above. But who would invest in a product with no record of timely technical support and terrible customer service? I could be wrong in my assumptions, but I am not convinced based on my dealings with the company. By the way, DCS has a really nice WEB site that makes the company look very attractive and promising, but my nephew can create such an illusion and he is only 10 years old.
Super Ram??? Tell me more please.
Super Ram??? Tell me more please.
12-10-2012, 12:06 PM
#7
should have said 'accell' super ram, here ya go
https://www.google.com/search?q=acce...2&ved=0CDoQsAQ
https://www.google.com/search?q=acce...2&ved=0CDoQsAQ
12-10-2012, 02:22 PM
#8
Le Mans Master
I am well aware of DCS and the Renegade, but my dealings with the company are very disappointing. I ordered a TPS harness from them on November 5th and paid for it through PayPal. They confirmed my order and accepted payment the same day, but I have not received my TPS harness as of this date. I have called them over 3X with no response and emailed them 2X with the following response: (paraphrased) We are back from Thanksgiving holiday and will process your order immediately. I have heard, nor seen anything since. My 3rd email was sent Saturday and no response. I only spent $35 with shipping and handling (and may have recovery options through PayPal) which I plan on exercising next week if I do not receive my order. You will spend much more for the un-proven Renegade through a company with lousy customer service, so beware!
