I have from time to time read where an alante intake is used on a 4.9 motor. I ws wondering what the benefits of that intake are, and can those intakes be converted to use a carburetor?

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87 fiero gt 4.9
99 trans am ls1

I have an allante intake on my 88 Formula/Gt. When I ran it on the dyno I pull 197 hp and 295 ft.lbs at the rear wheels. Having had both intakes on my car I would have to come down on the Allante intake side, my set of the pants meter says that my car is faster with the Allante and the WOW factor just adds to it



Joe Sokol

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85 SE Daily driver
88 Formula/GT 4.9 Allante Intake (My Baby)

quote Originally posted by Fieroking: I have an allante intake on my 88 Formula/Gt. When I ran it on the dyno I pull 197 hp and 295 ft.lbs at the rear wheels. Having had both intakes on my car I would have to come down on the Allante intake side, my set of the pants meter says that my car is faster with the Allante and the WOW factor just adds to it Joe Sokol

What did you do about the IAC??

quote Originally posted by Mickey_Moose: What did you do about the IAC??

there is no IAC on the allante, it uses an ISC motor just liek the regular 4.9L throttlebody does

The only mods that I did to my engine was to port the exhaust manifolds and the Intake were the runners pass by the lifter tubes. iI also installed a MSD 6A ignition system. I do have the Eldorado down and under Exhaust 2.5" from the manifolds into a 3" collector.

Joe Sokol

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85 SE Daily driver
88 Formula/GT 4.9 Allante Intake (My Baby)

quote Originally posted by Fieroking: The only mods that I did to my engine was to port the exhaust manifolds and the Intake were the runners pass by the lifter tubes. iI also installed a MSD 6A ignition system. I do have the Eldorado down and under Exhaust 2.5" from the manifolds into a 3" collector. Joe Sokol

those are great numbers on an essentially stock motor...

quote Originally posted by Fieroking: The only mods that I did to my engine was to port the exhaust manifolds and the Intake were the runners pass by the lifter tubes. iI also installed a MSD 6A ignition system. I do have the Eldorado down and under Exhaust 2.5" from the manifolds into a 3" collector. Joe Sokol

Joe,

What about PCM tuning?
Was anything changed to accommodate the Allante intake?
Also, What about EGR?
I understand that the later Allante intakes don't have EGR. I'm concerned that mine won't pass the e-check without it.

IMO, Fieroking's 4.9L installation is a very sharp-looking one, and 295 ft.-lbs. of torque (even with "only" 197 HP) sounds like his 4.9L Fiero would be great fun around town.

However, based on this other thread, titled, "Allante intake... vacuum routing....?" which is accessible via this link, https://www.fiero.nl/forum/Forum2/HTML/081709.html , it's not entirely clear (at least not to me) as to whether or not he has an EGR with his Allante intake. Hopefully Fieroking will chime in with the answers to that and your other questions, Raydar:

quote Originally posted by Raydar: What about PCM tuning? Was anything changed to accommodate the Allante intake? Also, What about EGR? I understand that the later Allante intakes don't have EGR.

I also have an Allante intake on my 4.9. Throttle responce seems better from the 4.9's stock intake. Other mods to my engine include ported heads, ported intake, 2.5" exhaust and a Delta camshaft. I'm still trying to get someone to burn me a new chip because my engine runs a bit on the rich side. I put down 190hp/282tq at the wheels with this setup and smoked out the shop because it runs soooo rich! I get in the 20's for fuel mileage on the highway and in the teens around town. Oh, and I am NOT running an EGR valve. There is also a slight modification/trimming of the 4.9 alternator bracket to make it work with the Allante intake. The Allante fuel rails also have to be used, the 4.9 rails will not bolt up and some of the sensors (Throttle position) use a different style connector than the 4.9. Just be sure to get the upper intake, throttle body, lower intake and fuel rails if you get an Allante setup.














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88 Coupe: Modded 4.9L V8 5 speed
84 Coupe: 4 Cyl 5 speed
www.geocities.com/fast88fiero

[This message has been edited by FieroMaster88 (edited 12-02-2007).]

Longer intake runners usually tend to boost the lower end of the power band.

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87GT - with 3800SC Series III engine, 4T65eHD
87GT - 3.4L Turbocharged engine, modified TH125H
" I'M ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by FieroMaster88: I also have an Allante intake on my 4.9. Throttle responce seems better from the 4.9's stock intake. Other mods to my engine include ported heads, ported intake, 2.5" exhaust and a Delta camshaft. I'm still trying to get someone to burn me a new chip because my engine runs a bit on the rich side. I put down 190hp/282tq at the wheels with this setup and smoked out the shop because it runs soooo rich! I get in the 20's for fuel mileage on the highway and in the teens around town. Oh, and I am NOT running an EGR valve. There is also a slight modification/trimming of the 4.9 alternator bracket to make it work with the Allante intake. The Allante fuel rails also have to be used, the 4.9 rails will not bolt up and some of the sensors (Throttle position) use a different style connector than the 4.9. Just be sure to get the upper intake, throttle body, lower intake and fuel rails if you get an Allante setup.

the delta cams drop-in cam isnt radical enough to make it run that rich. i think you have other issues, perhaps wring issues or bad sensors.. OR, maybe your O2(s) arent heating up enough to let the computer enter closed loop, i recommend installing a relay and heated O2 sensors...did you wire 12v+ to the Power steering input on the ecm? if you dont, the car will run rich..

quote Originally posted by aaronrus: the delta cams drop-in cam isnt radical enough to make it run that rich. i think you have other issues, perhaps wring issues or bad sensors.. OR, maybe your O2(s) arent heating up enough to let the computer enter closed loop, i recommend installing a relay and heated O2 sensors...did you wire 12v+ to the Power steering input on the ecm? if you dont, the car will run rich..

I believe we've discussed this in PM's before. Yes, there is 12V to the power steering input, I have installed heated o2 sensors and all of my sensors are reading properly, all the wiring is correct and there are no codes in the pcm. I'm sure it needs some different tuning. I've modified the ammount of air entering the engine a coupple of different ways. On any other car you would need a software modification.

quote Originally posted by FieroMaster88: I believe we've discussed this in PM's before. Yes, there is 12V to the power steering input, I have installed heated o2 sensors and all of my sensors are reading properly, all the wiring is correct and there are no codes in the pcm. I'm sure it needs some different tuning. I've modified the ammount of air entering the engine a coupple of different ways. On any other car you would need a software modification.

yeah, just because a sensor is "reading" doesnt necessarily mean it is good. on the highway, you should get 28-30MPG with a stock or a fastchips tune, and about 20-22 in the city, even with the drop in cam... now, if you had installed larger valves, i would say it needs a retune, but it shouldnt...

also, you wired 12v+ to the power steering input, but did you test it with a digital multimeter at the ecm connector after the install? also, im curious, what fuel pump are you using and what is your fuel pressure at the rail? are the injectors the stock caddy injectors?

The only part of the EGR system on my Allante is the vacume operated valve that mounts on the side of the throttle body. I installed it when I did the change over, however I have found that it makes no difference whither it is connect or not.

I made no changes to my PCM tuning. The chip was programmed by Rockcrawl ( Jon Langer) when I did the initial build.

I had the same problem with the car running very rich, through all my reading and work on the engine I found that the after market (Bosch) O2 sensor was the culprit. I changed to a GM O2 sensor (at least twice the price) but the car runs totally different after I installed it. My car idles at 700 rpm and is as smooth as silk driving around. But the biggest difference is the back of the car doesn't get covered in black soot any more.

I get low 20's in town and high 20's 0n the highway.

Joe Sokol

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85 SE Daily driver
88 Formula/GT 4.9 Allante Intake (My Baby)

quote Originally posted by FieroMaster88:

hey that looks mighty familiar

One other thing I do have is a true cold air intake, it is basically a 3 inch tube from my side scoop to the engine.



Joe Sokol

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85 SE Daily driver
88 Formula/GT 4.9 Allante Intake (My Baby)

Pretty good guess, Aaron, seeing as how when we dyno'd ours we had 175 at the wheels and the poster with the Allante intake had 197 rwhp. I'm surprised it makes that much difference, but that would be a nice boost since it apparently does.

John Stricker

quote Originally posted by aaronrus: first off, dont carb the 4.9L, you are robbing it of its fuel economy AND power/TQ. the allante intake added 20 HP to the 180 HP PFI engien in 1990, so i would imagine similar gains on a 4.9L..

quote Originally posted by aaronrus: yeah, just because a sensor is "reading" doesnt necessarily mean it is good. on the highway, you should get 28-30MPG with a stock or a fastchips tune, and about 20-22 in the city, even with the drop in cam... now, if you had installed larger valves, i would say it needs a retune, but it shouldnt... also, you wired 12v+ to the power steering input, but did you test it with a digital multimeter at the ecm connector after the install? also, im curious, what fuel pump are you using and what is your fuel pressure at the rail? are the injectors the stock caddy injectors?

Ok, should let you know I'm not retarded. I'm a master ASE Certified technician. I know how to test sensors and what the readings should be and have a scantool to do it with. I know what fuel pressures should be. I've also tested everything over and over again as have some of the people I work with and there are no problems found. I do appreciate you trying to help but am getting a little tired of you telling me I don't know what I am doing.

quote Originally posted by FieroMaster88: Ok, should let you know I'm not retarded. I'm a master ASE Certified technician. I know how to test sensors and what the readings should be and have a scantool to do it with. I know what fuel pressures should be. I've also tested everything over and over again as have some of the people I work with and there are no problems found. I do appreciate you trying to help but am getting a little tired of you telling me I don't know what I am doing.

they were simple questions aimed at trying to figure out what is wrong. im sorry i cannot read your mind and discover that you are "ASE certified".

another consideration: this is not the first time i have heard of someone using one of rockcrawl's chips running rich even after using heated O2s and wiring everything properly. In fact, it is the 4th time. If you send me a chip, i'll send you a stock deville program with the VATS removed so you can test that theory out, just send $5 with it for return shipping. also another idea: if you can get ahold of a chip from a '91-'92 allante, i can remove the vats on that and you can test that chip out as well, see which fuel/ignition maps work better for your setup.

quote Originally posted by Fieroking: One other thing I do have is a true cold air intake, it is basically a 3 inch tube from my side scoop to the engine. Joe Sokol

You know, oddly enough, cold air makes a HUGE difference with this engine

I ran the stock 4.9 intake at first. Performance was good and I didn't think the Allante intake would make much difference in performance. But I found one and bought it because it looks so much better..... and to my surprise felt a very noticeable improovement in the 3000-5000 rpm range.

Here are some current pics...

Nice installation, v8fiero400!

I agree with you about the appearance of the Allante manifold and the stock 4.9L manifold:

quote Originally posted by v8fiero400: I ran the stock 4.9 intake at first. Performance was good and I didn't think the Allante intake would make much difference in performance. But I found one and bought it because it looks so much better..... and to my surprise felt a very noticeable improvement in the 3000-5000 rpm range.

I also think it's great when you can find a better-looking manifold that also works better than the stock 4.9L manifold (as others on this thread also have reported).

quote Originally posted by FieroMaster88: ...The Allante fuel rails also have to be used, the 4.9 rails will not bolt up ...

How much different are they.
Can they be made to work if the Allante rails are not available?
What would be involved?

I've got both out in the shed... IIRC, the mounting tabs are all in the wrong places. I don't recall if there are any problems with tubing interference or injector placement.

not to high jack this thread, why do the 4.9l make no horsepower?
looks like you guys have a hard time breaking into the 200hp mark....
whats it like driving a light car with a bunch of torque and no horsepower?


i have a stock ford 302 engine in my fiero and it pulls of decent 1/4 mile numbers, estimate hp is 230hp... and comparatively speaking they are both 4.9l, intakes the same type (allante)...

quote Originally posted by 2feido: not to high jack this thread, why do the 4.9l make no horsepower? looks like you guys have a hard time breaking into the 200hp mark.... whats it like driving a light car with a bunch of torque and no horsepower? i have a stock ford 302 engine in my fiero and it pulls of decent 1/4 mile numbers, estimate hp is 230hp... and comparatively speaking they are both 4.9l, intakes the same type (allante)...

I don't know if you mean well and ask questions for enlightenment, or if you are trawling to start a flame war...but either way, saying the 4.9L makes no power is not going to be productive.

But to answer your question, the 4.9 was never intended to be a high horsepower motor. Cadillacs of the mid 90s were not high speed performance cars. And 200 hp is a respectable number for that era. The engine doesn't really respond well to mods because it produces maximum torque at low rpm. In my humble opinion if you want a high revving high hp motor it's much easier to start with a different engine. The 4.9 should be enjoyed for what it is...an inexpensive, light weight V8 that does not require an adapter plate to fit in a Fiero.

quote Originally posted by Fieroking: The only part of the EGR system on my Allante is the vacume operated valve that mounts on the side of the throttle body. I installed it when I did the change over, however I have found that it makes no difference whither it is connect or not. I made no changes to my PCM tuning. The chip was programmed by Rockcrawl ( Jon Langer) when I did the initial build. I had the same problem with the car running very rich, through all my reading and work on the engine I found that the after market (Bosch) O2 sensor was the culprit. I changed to a GM O2 sensor (at least twice the price) but the car runs totally different after I installed it. My car idles at 700 rpm and is as smooth as silk driving around. But the biggest difference is the back of the car doesn't get covered in black soot any more. I get low 20's in town and high 20's 0n the highway. Joe Sokol

do you have a part number on the GM sensor, and is it the heated type?

quote Originally posted by jscott1: I don't know if you mean well and ask questions for enlightenment, or if you are trawling to start a flame war...but either way, saying the 4.9L makes no power is not going to be productive.

What? Since when is the truth not productive? The 4.9 is a stone. This, of course, is a big part of the reason it's cheap...
It is such because it has terrible cylinder head and intake flow. The intakes were seriously squashed to fit under relatively low Cadillac hoodlines. With decent heads and intake on it, it could make 400 HP, just like a Ford 5.0.

quote Originally posted by Will: I'm curious about your 5.0 build. Do you have it documented anywhere on the internet? As I said above, the 4.9 heads and intakes--even the Allante--just don't flow. At 92mm x 92mm, it's also got a pretty small bore compared to a Ford 302, which further limits it. There's a build thread on this forum someplace in which the author does a pretty much all out build of a 4.9. He uses Northstar pistons (overbore to 93mm and compression to 10ish), ported exhaust manifolds, ported heads with bigger valves, ported Allante intake, reground cam and a lot of other little mods I'm forgetting. He made 235 HP to the ground. I'm not knocking his ability, but for a 5 litre V8 to only put 235 to the ground is pretty pathetic. The 4.9 just doesn't have any performance potential with the stock heads and intakes.

Will. why are you beating a dead horse, this subject has been beaten to death before.

Nobody chooses a 4.9 as an ultimate performance engine, it's shortcomings are known, it is an effective swap in terms of cost, ease of installation, performance (the torque makes for a really quick accelerating car from stoplight to stoplight) and yes sound. we already know that it's not your choice, it's been mine in the past, but I'm doing something different now.

So how about you stop trashing a tech thread and lay off the 4.9. BTW the build you talked about, when he dynoed the combo there were valvetrain issues as well as some tuning issues.

If you can't see the future,
your not driving fast enough. Joe

'Cause a guy with a Ford 5.0 asked... the displacement invites comparison.

The 4.9 definitely has its uses. It's great if you need not more than 200 HP and a buttload of torque in a lightweight, cheap package. I'd put one in a Triumph Stag and it probably works well in other small lightweight British sports cars. It would be amusing in a Miata. I've seen a website in which a guy puts one in a Suzuki Samurai (?).

It's just not a barn stormer.

quote Originally posted by 2feido: not to high jack this thread, why do the 4.9l make no horsepower? looks like you guys have a hard time breaking into the 200hp mark.... whats it like driving a light car with a bunch of torque and no horsepower? i have a stock ford 302 engine in my fiero and it pulls of decent 1/4 mile numbers, estimate hp is 230hp... and comparatively speaking they are both 4.9l, intakes the same type (allante)...

Well, if you have a stock 302 then you are making about 180-185 at the wheels. No one is complaing that it doesn't pull well, just that it runs out of breadth fast (4500rpm). Adding the Allante intake kicks us up to 190+rwhp and lets it breath to a bit over 5000rpm. I've seen many 302 dynos in my day and most end up around ~232rwhp with lots of mods, which has also been done on the caddy motor by one member here. Also, it's easy to get headers for a 302, not so easy for a Caddy 300. To me, having the Caddy motor bolt up directly to the tranny with no adapter plate is a win, as is the lighter weight of the install.

Unfortunately, due to a poor installation job by the Fiero Factory, I am missing a boss for one of the bolts of the front engine mount. Does anyone know of where/how I can fabricate a second/additional mount on the firewall side of the motor?

Anyone know who burns a chip for 2 o2's for more HP?

I am having a Allanted intake swap done now.
The issue of the throttle cable has come up. Use a new GM one or can the stock 4.9 one be used on the Allante throttle body?

quote Originally posted by lou_dias: I am having a Allanted intake swap done now. The issue of the throttle cable has come up. Use a new GM one or can the stock 4.9 one be used on the Allante throttle body?

as far as i know, the stock 4.9L can be used. the connector is the same, although i am not sure about the length.

did you sort out the missing boss/bolt for yoru front engine mount from the fiero factory?

My tech welded the mount to the AC mount for extra support. So ofcourse the next weakest link broke : tranny mount.
Also just found a cracked valve cover on the front (firewall) side. No wonder I've been bleeding oil. Great low miles engine they sold me...

GT told me to use the 87 4cyl throttle cable.

quote Originally posted by madbrad01: Anyone know who burns a chip for 2 o2's for more HP?

i do.. PM me