Hello everyone! It's been a long time. I'm back on the forum because I just picked up an 86 1/2 fiero gt with a nice little laundry list of goodies done to the 2.8 including: bored over to 3.2, 3.1 crank neutral balanced with 7.25" flywheel, ARP rod bolts, a comp cam, 1.6 roller rockers, ported heads, 2.44 g/s injectors, a performance true dual exhaust and a chip to manage the calibration for the injectors.
Now, one of you I suspect, may find that this all sounds familiar. If that's the case I'd love to find the previous owner on here and talk. But that's not why I'm making this thread. Let's talk intake.
So for all of my research, it seems that our cars have trouble breathing around 4500, give or take. And the guy I'm buying this from specifically told me it drops off at 5k. Based on what I've seen, the restrictive intake plenum looks guilty, at least in part. And I wondered what people have done to help this engine breath.
I've seen the Trueleo intakes out there, which are out of production, and I have seen claims here on this forum that they don't age well and have never provided dyno results, at least with a same before and after (no addition modifications between dyno)
I've seen that Black Top Racing was working on a dual intake, which looked cool and probably expensive, but from what I can tell, they are out of business now.
I've heard of a member here using the intake from a 2.8 firebird with a 3D printed adapter for the throttle body. I'd be curious what the benefits are to this one, just read about it. No details on CFM increase.
I've also considered going small, reliable forced induction, mostly just to get it breathing right in the high RPMs. maybe 6-9 psi. But I'm not sure what compression it's running. I'm not even sure what the stock compression is, or if people have had bad experiences going forced induction on the ol 2.8.
At the end of the day, it looks like all of the online stores that I used to dream shop for performance parts just a few years ago are gone. V8 archie looks like it's still around. The Fiero store, though that all looks like support for stock parts. I'd really like to come up with a solution for this anemic intake, as I suspect with everything that has been done to the engine, if it could breath proper, it would probably wake up even more. Any suggestions? And am I missing any good online performance and styling product stores that are still around?
Thanks in advance, I'm glad to rejoin the ranks of fiero owners!
I have the ported exhaust, "Dawg Style" UIM, relieved y-pipe, hi-flow cat, Hypertech chip and a 57MM throttlebody. Basically all the breathing mods. Each one added a little to the performance but then I did the 1.6 rockers and WOW! what a difference.
I consider the rocker mod to be the one that brought all the pieces together, giving me a very nicely balanced car which also looks completely stock.
As for the RMP power limit, I can say unequivocally that the rockers made a huge difference. Where the stock car ran out of breath at about 4500RPM's, the modded car easily pulls all the way to 5500RPM's and there still some left but that's as far as I want to push a 30 year old engine even if it only has 60K miles on it. In fact, being an automatic I have to manually shift because the factory shift point is way too low for the modded engine.
jjd2296 - You've gotta let me know how that turns out. Looks like you've put some real effort into that! Looks good.
RayOtton - Now that's what I'm talking about, I really just wanted to get her breathing right up to at least 5500 maybe with a little more if I'm even in a situation where I need to tap it. I plan to eventually autocross her, so for just getting to that corner without shifting up and then down it could be useful. The throttle body and Dawg Style UIM's, who made them? Are they still around? And what kind of modification did you need to made the throttle body electronics play nice?
Fieroguru - You're the man! Thanks for that resource!
Thank you everyone for the constructive on topic responses! That's what I'm talkin about!
[This message has been edited by SpaceLion (edited 03-29-2020).]
Originally posted by SpaceLion: The throttle body and Dawg Style UIM's, who made them? Are they still around? And what kind of modification did you need to made the throttle body electronics play nice?
The throttle body was bored by a member on here, about 5 years ago so I don't recall the name. Try a search of the site, if nothing comes up drop me a line and I'll see if I have an invoice laying around.
I bought the "Dawg style" UIM from a member here who listed it in the mall section. I don't know if anyone is making new ones but they do pop up now and again the the mall.
I didn't do a thing to the electronics other than replace the standard chip with a Hypertech one. Lots of people say they don't do anything but advance the timing curve and add a bit more fuel but hey, isn't that exactly what you need with airflow improvements?
[This message has been edited by RayOtton (edited 03-29-2020).]
Originally posted by RayOtton: Lots of people say they don't do anything but advance the timing curve and add a bit more fuel but hey, isn't that exactly what you need with airflow improvements?
No, you need timing retard with airflow increases.
Think about how a car has a vacuum advance can on the distributor; with more vacuum (i.e. light loads, low airflow), the timing must be more advanced.
The denser the air/fuel charge is in the cylinder, the faster the flame propagates away from the spark plug; the air/fuel charge is consumed more quickly.
If the spark is too advanced, you're just building up too much pressure, too early, while the piston is still rising in the compression stroke. This robs torque from the engine.
No, you need timing retard with airflow increases.
Think about how a car has a vacuum advance can on the distributor; with more vacuum (i.e. light loads, low airflow), the timing must be more advanced.
The denser the air/fuel charge is in the cylinder, the faster the flame propagates away from the spark plug; the air/fuel charge is consumed more quickly.
If the spark is too advanced, you're just building up too much pressure, too early, while the piston is still rising in the compression stroke. This robs torque from the engine.
We've had this discussion before and at the time I explained I'm no engineer so I can't argue theory. However, hopefully you recall I do have empirical DATA to back up my point.
Originally posted by RayOtton: I didn't do a thing to the electronics other than replace the standard chip with a Hypertech one. Lots of people say they don't do anything but advance the timing curve and add a bit more fuel but hey, isn't that exactly what you need with airflow improvements?
You asked a question (question mark at the end of your sentence), so I shared my point of view...
quote
Originally posted by RayOtton: We've had this discussion before and at the time I explained I'm no engineer so I can't argue theory. However, hopefully you recall I do have empirical DATA to back up my point.
There's no need to talk about peoples' occupations... arguments should stand based on their own merit, not because of a person's credentials.
If data doesn't agree with theory, then either the data is wrong, the theory is wrong, or both are wrong. If there is an inconsistency, that means we have some learning to do.
All propositions shall not be accepted at face value (including my own; nobody's word should be taken as-is). Everything should be scrutinized and picked apart... what remains after the collective debate is hopefully the truth.
By this method of collective verification and scrutiny, we can create a repository of quality information in the PFF archives.
[This message has been edited by pmbrunelle (edited 03-30-2020).]
When I started the quest on making the iron head breath, my first test was installing a dual 48mm TPI TB on a box welded to the top of the upper plenum which gave more volume to the intake system Those were the ONLY changes and the numbers increased +5WHP & +5WTQ. That result was everything I needed to know to start working on a top end system to uncap the power capabilities of these iron heads marvels.
Welcome back to the forum and we are here to help!
When I started the quest on making the iron head breath, my first test was installing a dual 48mm TPI TB on a box welded to the top of the upper plenum which gave more volume to the intake system Those were the ONLY changes and the numbers increased +5WHP & +5WTQ. That result was everything I needed to know to start working on a top end system to uncap the power capabilities of these iron heads marvels.
Welcome back to the forum and we are here to help!
Rei
Wow, sounds good! You wouldn't happen to have a picture of that setup would you? And where did you get the TB? I know you said that it gave you +5 HP/TQ but I would be curious how it effected the entire power band, particularly the top, since my goal is to keep the power from falling off as long as I can and as much as I can to be able to hold gear longer in some situations. And for what I consider to be a more fun engine dynamic.
Wow, sounds good! You wouldn't happen to have a picture of that setup would you? And where did you get the TB? I know you said that it gave you +5 HP/TQ but I would be curious how it effected the entire power band, particularly the top, since my goal is to keep the power from falling off as long as I can and as much as I can to be able to hold gear longer in some situations. And for what I consider to be a more fun engine dynamic.
I'll see if I can find pictures of it, I believe I still have the Dyno sheet somewhere.
This is my 2.8 with the top end I developed. Heads, cam and intake. The aftermarket parts you can buy from Comp Cams, Truelo and other vendors will never get you near this results, they are generic parts. This 2.8 had more power than any 3.4 except mine. That's why I always stress the entire package gets the results you are looking for, the right parts. Miss match parts make it worse. Look at the dyno sheet below for example, If you follow the HP line of the stock 2.8 WHP on this dyno sheet it'll be at 94WHP@6000. At that same rpm the Supernatural 2.8 (I call my parts "Supernatural" by the way) made 166WHP (The most WHP it made was 173WHP). That is 72WHP@6000RPM gain, all naturally aspirated, not turbo or supercharged. And that was with email chip tuning. If I had back then the means to tune it like I do now I can guarantee you I could've made 200+WHP with this 2.8.
This is my 2.8 with the top end I developed. Heads, cam and intake. The aftermarket parts you can buy from Comp Cams, Truelo and other vendors will never get you near this results, they are generic parts. This 2.8 had more power than any 3.4 except mine. That's why I always stress the entire package gets the results you are looking for, the right parts. Miss match parts make it worse. Look at the dyno sheet below for example, If you follow the HP line of the stock 2.8 WHP on this dyno sheet it'll be at 94WHP@6000. At that same rpm the Supernatural 2.8 (I call my parts "Supernatural" by the way) made 166WHP (The most WHP it made was 173WHP). That is 72WHP@6000RPM gain, all naturally aspirated, not turbo or supercharged. And that was with email chip tuning. If I had back then the means to tune it like I do now I can guarantee you I could've made 200+WHP with this 2.8.
Man! That is just awesome! Look at that new torque and HP curve!! That's exactly what I'm talking about. That's why I started this thread. You've show real evidence that the 2.8 is capable of not only breathing up to 6K but make usable power too! I mean look at those new curves, that is impressive. So obviously you fabricated that yourself. Did you have to modify the hood to get it to close properly? And I might have missed it, but what dual intake did you use on your custom plenum? Man, again, very impressed. That's exactly what I'm shooting for. Couldn't agree more about the correct combination of synergistic parts. I think with what the previous owner did, I'm off to a good start of supporting parts. That's why I'm really concentrating on the airflow. It seems to be the only thing the setup is really missing to get the best out of it.
I've got the intake manifold available (if someone is interested) off of this setup found in the junkyard. Just the intake. I took details shots of the TB used but the price was too high on that.
Originally posted by pmbrunelle: You asked a question (question mark at the end of your sentence), so I shared my point of view...
Obvious to most members, my question was rhetorical.
quote
Originally posted by pmbrunelle: There's no need to talk about peoples' occupations... arguments should stand based on their own merit, not because of a person's credentials.
WUT? This is a non-sequitur if ever there was one. No one's talking about what people do for a living, I simply stated that I'm not an engineer so I can't speak about technical issues. If I had questioned YOUR credentials then you might have a point, otherwise, it seems you are looking for an argument that will add nothing to the discussion.
quote
Originally posted by pmbrunelle: If data doesn't agree with theory, then either the data is wrong, the theory is wrong, or both are wrong. If there is an inconsistency, that means we have some learning to do.
All propositions shall not be accepted at face value (including my own; nobody's word should be taken as-is). Everything should be scrutinized and picked apart... what remains after the collective debate is hopefully the truth.
By this method of collective verification and scrutiny, we can create a repository of quality information in the PFF archives.
The newer version (TR2)was installed and dynoed. This one has wider runners (used Camaro mid runners) and added plenty of volume. It picked up 13whp at peak and kept that gain to 6000rpm. The torque band stretched 2000rpm and picked up about 12WTQ@6000rpm. Look at the dyno sheet of the TR1 vsTR2 intakes so you can see the improvement!
This is how it looked on the car. Unfortunately you can't have an intake that supplies the airflow the engine needs to breath and keep it under the hood. That's why the factory upper plenum is so restrictive, packaging.
Then I made another version (TR3) and applied my findings to the intake on the right. It's basically the same concept but with a bit of physics applied. It has much more shorter runners to improve top end power and decreasing radius plenum open runners. This newer intake gave me an extra 7WHP from 6000 to 6500rpm and without affecting the power and torque curve in the mid-range.
TR2 vs TR3
So, based on my research, the lesson learned was that the more plenum the intakes got the more power output. I also learned that I could place power anywhere by using different runner lengths and shapes.
I t seems that most of these mods aim at 7-9000 rpm out of the 2.8....I don't think that really makes sense. I have a 3.4 F-body long block under my stock induction system. I have read about someone testing an intake on a flow bench- with a enlarged throttle-body and then with the "neck" enlarged...The "Neck" enlargement was the big (Real) improvement.
Here is what I have done to mine.....(Haven't painted nor installed it tho)
[This message has been edited by cvxjet (edited 03-31-2020).]
I t seems that most of these mods aim at 7-9000 rpm out of the 2.8....I don't think that really makes sense. I have a 3.4 F-body long block under my stock induction system. I have read about someone testing an intake on a flow bench- with a enlarged throttle-body and then with the "neck" enlarged...The "Neck" enlargement was the big (Real) improvement.
A flowbench is a tool to be used as a means to have an idea of your goals, I personally don't care about flow numbers. There are a lot of variables a flowbench doesnt test for. For example, according to the flowbench my iron heads were only good for 242WHP max. The engine made 304WHP, 62WHP extra of what the holy flowbench predicted. How can that be?!! Well, the same way you can add a turbo to an engine that according to the flowbench would be impossible to reach 300WHP, now with the altered atmospheric pressure the flowbench predictions become obsolete. That same way you can design an N/A system where the TB, intake, cam and head act like a torque converter and multilply the rate of incoming air velocity to increase VE and power. That's only one variable! Takes a lot of thinking, Its tedius work but it can be done. Turbo or supercharge is the easy way out if you don't want to put the effort.
CVXJET, I like your improvement on the stock upper plenum and can't wait to see the results, good luck my friend!
I've got the intake manifold available (if someone is interested) off of this setup found in the junkyard. Just the intake. I took details shots of the TB used but the price was too high on that.
So how much are you selling the intake section for? And what throttle body was on there so I could try to find it.
Also, I wonder if the lower intake plenum will choke out the gains of the ported upper... Right?
I sent and email to the Trueleo guys, and I actually got back an email like quick! It was his son Troy, who told me that he doesn't have the tools anymore to make them. And the most ineresting bit about the email was that he told me that they only made 15-20 total. So they are very rare. He also said that when he has seen them pop up on ebay, they are selling for way more than they sold them for. It's really too bad, it looked like exactly what I'm looking for.
That being said... I might be interested in that intake sourmash, I mean it is ported right?
And if anyone else is willing to sell their skills, or intake for matter. I'm open to paying someone with experience to port an intake for me, or a fabricated setup if you're up to making one for the right price. Keep in mind the list of mods in my initial post for this thread. That's why it needs more CFM, and there I explain my goals for the car.
The cvxjet modification is called the Dawg mod. He might still do those. Around here machine shops that weld like that charge $90 per hour and none convinced me they could do it reliably. Sad. This one I have is an alternative form to get around the neck restriction. The builder used a DIS setup like the Camrobird 3.4 setup as you can see the coils on the right side of the full engine shot. $50 bucks plus shipping and it's yours. Here's the shots of the TB it had on it. Someone should be able to recognize it or it could be sized by the opening and bolt pattern. Using a stock Fiero TB when this was built would be a big miss, so I'm sure it's larger. It appears to be a Fiero intake, and it's a straight-shot design now. No throat to choke,
[This message has been edited by sourmash (edited 04-01-2020).]
I did all of the cutting and fitting- then had my buddy weld it up for me- He was a welder at NAS Alameda back in the 80s-90s- He had actually gone to Metallurgy classes- so he actually knows what is going on while he is welding.....I needed my boat trailer shortened to fit in my garage, so we spent a whole Saturday cutting the front, bending, and then rewelding it together- that was back in 2000 and it is still solid!
The crazy thing is he would not let me pay him; Later, I bought a second copy of a book I had been given for Christmas; "The Muscle Car Chronicle". It is a very cool book with 15-20 pages devoted to each year from 1960 to 1972, (Hardback).....I gave him the book and he looked it over then tried to give it back ("No- it's yours!!")...Then he starts to pull out his WALLET!....."Dude! You never let me pay for the trailer welding! Take it!"
I'm waiting to sand-blast it to get the old paint off so I can spray the new paint- and the Virus-Crisis has stopped all of that stuff.....
Here it is! that same 2.8 testing at a road course. I had street tires on porpuse. My goal was just to drive the car and feel the overal set up. The transmission was not meant for this track. Enjoy! https://youtu.be/apPx7Tu3Q9E
[This message has been edited by La fiera (edited 04-02-2020).]
PM sent. Just to reiterate, what was the issue with the TB not being included? You said it was too expensive to mention? So it's not for sale? Or you just feel like whatever number you put out there would melt my face off? Or did I misunderstand completely?
quote
Originally posted by sourmash:
The cvxjet modification is called the Dawg mod. He might still do those. Around here machine shops that weld like that charge $90 per hour and none convinced me they could do it reliably. Sad. This one I have is an alternative form to get around the neck restriction. The builder used a DIS setup like the Camrobird 3.4 setup as you can see the coils on the right side of the full engine shot. $50 bucks plus shipping and it's yours. Here's the shots of the TB it had on it. Someone should be able to recognize it or it could be sized by the opening and bolt pattern. Using a stock Fiero TB when this was built would be a big miss, so I'm sure it's larger. It appears to be a Fiero intake, and it's a straight-shot design now. No throat to choke,
Also Sourmash, can you measure the opening of the intake? It looks like it matched the throttle body. That would help me narrow down what it was. I wonder is a stock fiero TB has enough meat on it to port it to match. Also, I think I get it now. I was too expensive at the junk yard so you left it..
[This message has been edited by SpaceLion (edited 04-04-2020).]
All of the above mods look good and will help the 2.8L breath but on my first Fiero I just bolted on a turbo that I purchased at the junkyard for $30. It came from a Ford 2.5L engine Rebuilt it for $30 in parts, bolted it on; breathing problem solved and a 0-60 time in about 6.5 seconds. Big improvement in performance but this mod does require some welding skills for the plumbing. Total cost with all the pipes was under $200 but that was a while ago.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Yeah I definitely thought about forced induction solutions to get the air volume right. Unfortunately I don't have the skills or equipment to do that. I'm also assuming you had to have the fuel and ignition tuned to your new setup. So all things considered, a turbo would probably cost me quite a bit. Plus there is the issue of the bored out and modified engine that I'm working with. I'm not sure what the new compression is yet, or how much boost it could reliably handle. I was actually hoping to find a 5-7 psi superchanger that might work. Since at least for me, superchargers seem to be more straight forward in their installation and require less skill usually. Plus I'm a fan of SC powerband shape over turbo powerband shape. I like smooth predictable power. But hey! If I could find someone willing to install and tune for a small turbo setup under 1k, I would almost definitely do it. For now though, I'm just pushing forward with trying to get her asthma cured.
I got an Ashma pump that will help you. Like Dennis said, the other way is a turbo which it produces a lot of heat in the engine bay. Good luck with your goals!
I got an Ashma pump that will help you. Like Dennis said, the other way is a turbo which it produces a lot of heat in the engine bay. Good luck with your goals!
Have you ever done one of your fancy intakes with a turbocharger?
I follow Richard Holdner on youtube, he has shown on a large variety of builds that improving the NA engine is the best way to make more power under boost.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Yeah I definitely thought about forced induction solutions to get the air volume right. Unfortunately I don't have the skills or equipment to do that. I'm also assuming you had to have the fuel and ignition tuned to your new setup. So all things considered, a turbo would probably cost me quite a bit. Plus there is the issue of the bored out and modified engine that I'm working with. I'm not sure what the new compression is yet, or how much boost it could reliably handle. I was actually hoping to find a 5-7 psi superchanger that might work. Since at least for me, superchargers seem to be more straight forward in their installation and require less skill usually. Plus I'm a fan of SC powerband shape over turbo powerband shape. I like smooth predictable power. But hey! If I could find someone willing to install and tune for a small turbo setup under 1k, I would almost definitely do it. For now though, I'm just pushing forward with trying to get her asthma cured.
If I can find them, I do have programs ( as do others) on Tunercat that have the timing tables and fueling for the 2.8L turbo. Yes you must introduce fuel and have timing retard with boost. This requires a 2 BAR MAP sensor The stock 2.8L should be able to take 5-6 psi of boost without issues but if you go hog wild on boost its BOOM!. IMO, turbos are easier to install than a supercharger. A while ago there was a guy in eBay that sold a Fiero turbo kit for $1,000. It used a Chinese turbo, had all the installation parts (exhaust plumbing) , except the program and the 2 BAR MAP. A friend of mine purchased one and it worked but he had to improve the oil feed line. As for engine compartment heat there is more but I got around this by wrapping the crossover pipe and mounting the turbo close to the air grill. When I view all the work that guys are doing to improve the plenum; the first thing that comes to mind is the turbo as a solution.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
[This message has been edited by Dennis LaGrua (edited 04-05-2020).]
I'm definitely interested, but I have to research a bit more on tuning so I don't get a bunch of crazy codes and running issues. I also am in the process of buy another intake from another member, though I'm considering also picking this one up since it seems to move the power band up. Kind of my goal.
I got an Ashma pump that will help you. Like Dennis said, the other way is a turbo which it produces a lot of heat in the engine bay. Good luck with your goals!
Have you ever done one of your fancy intakes with a turbocharger?
I actually did. It was back in 2002 when I had a 1989 Dodge Spirit Turbo. 2.5 SOHC 8 valve head. Built the bottom end forged and fully balanced and started with 250WHP and 275WTQ First I altered the stock intake and it made improvements, then I build one from scratch to suit my goals, not power because the car was heavy but low to mid grewsome torque. It took me a couple of years but when it was ready for ME with 30psi, water/meth, big plenum custom intake, modified exhaust manifold to accomodate a custom ball bearing T61 hybrid turbo with .048 turbine resulted in 420WHP@4000 and 560WTQ@3500 and it was over 400WTQ off throttle! I coul've made more power but I decided to stick with the smaller turbine, it had no lag.
The gains of the custom intake didn't make much difference in this application so I decided to concentrate my efforts in the design a turbo to match my needs, not what everybody else was running at the time.
