Anyone remember the Isuzu Impulse? That's the car that had the green "Handling by Lotus" badges on the front fenders. It was essentially a Chevette with a fancy body on it - and presumably some tweaks to make it handle better. Or were there?
If you check the Moog Suspension catalog for all the front suspension components (bushings, ball joints, etc.) for the Isuzu Impulse you'll find that it uses the same parts as an 84-87 Fiero. Every part - exactly the same.
I believe that the truth is that both the Impulse and Fiero inherited their front suspension from the Chevette. So where did Lotus figure in? I dunno...
Suspension tuning is all in the details. Lotus tuned the suspensions of several cars by specifying bushing stiffness, alignment specs, shock valving and anti roll bar sizes. The parts like ball joints would be the same, as for Moog bushings, remember that Moog does not supply every variation in a particular bushing set, just a good quality "one size fits all" replacement.
Yes also the Impules and the Lotus Ellan(spelling) are the same chasis. you can look that up and find it to be true online. My budy had an Impulse. And as for the Lotus design Fiero suspention. that rummor is false.
------------------ Fierokid's baby: R.I.P.V-6 Swap 1987 Blue Fiero sport coupe White 1988 Fiero Formula AIM: Fierokid87 Rate Me Please 2.9L V-6: 2030 Compucam, Darrel Morse Fuel Pressure Regulator, 9.5:1 comp, zeroed out balanced crank, connecting rods matched, MSD 6A ignition box and Blaster GM style coil, Darrel Morse Bored out TB and intake, 19# Mustang Injectors, Removed TB coolant lines, Darrel Morse Dogbone strut, and more to come
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10:02 PM
Fierochic88 Member
Posts: 4987 From: Staunton, VA Registered: May 2001
Hulki said the only role Lotus played in the Fiero was that GM looked over the Lotus paint factory and decided their methods were too antiquated for GM use.
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10:13 PM
Razor_Wing Member
Posts: 1753 From: Blowing Rock, NC, USA Registered: Apr 2003
Lotus Had NOTHING to do with the desighning of the fiero, however, GM DID buy 3 ferris to desighn body and suspension componts after . And I 2nd the fact of the 88 spension being desighned by lotus 100% false. This has been said by GM AND Lotus, as well as the engineers that DID the redesighning.
------------------ '86 GT - 4speed RED! Pioneer Radio
<>{RazorWing}<> (I need a REAL sig, lol)
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10:22 PM
derangedsheep Member
Posts: 3089 From: Myerstown, PA Registered: Mar 2003
Hulki said the only role Lotus played in the Fiero was that GM looked over the Lotus paint factory and decided their methods were too antiquated for GM use.
I see some confusion here, the later FWD Impulse (also with Lotus tuned suspension) donated its drivetrain to the short lived FWD Lotus Elan (not the original 60s/70s RWD Elan). The earlier Impulse was on the Chevette chassis with bodywork by Italdesign, beautiful, if unsophisticated, car. With the Lotus tuning the car handled very well (I keep telling people that the Chevette was just a cut rate version of the Opel Kadette, a car with some success in racing in Europe. GM, in their ultimate wisdom, chose to offer a much less powerful engine in the North American version, the Chevette, and then pulled the handling package from the options list after only a couple of years. Compare the Chevette suspension to the RWD ox carts most import manufacturers were offering in the late 70s and you can see that it was quite sophisticated. It was the super el cheapo interior that really set the Chevette apart.)
Ira
BTW a suggestion to the extreme "typing impaired", why don't you type up your responses in a word processor and then paste them into the forum message space, that way there would at least be a spell check. I hope no one is offended by this, but some of the responses I see are nearly impossible to read. Everyone makes mistakes but usually you can follow what they are trying to say, but when it gets too bad you tend to just ignore the post.
[This message has been edited by Monza76 (edited 08-15-2003).]
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07:27 AM
Raydar Member
Posts: 41474 From: Carrollton GA. Out in the... country. Registered: Oct 1999
I see some confusion here, the later FWD Impulse (also with Lotus tuned suspension) donated its drivetrain to the short lived FWD Lotus Elan (not the original 60s/70s RWD Elan). The earlier Impulse was on the Chevette chassis with bodywork by Italdesign, beautiful, if unsophisticated, car...
Ira
Yeah. I'm confused, too. I just can't picture the early Impulse. Unless... Were the later ones the same car that shared a body and Chassis with the Geo Storm?
------------------ Raydar
88 3.4 coupe. 17s, cut springs 'n all.
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07:33 AM
Razor_Wing Member
Posts: 1753 From: Blowing Rock, NC, USA Registered: Apr 2003
BTW a suggestion to the extreme "typing impaired", why don't you type up your responses in a word processor and then paste them into the forum message space, that way there would at least be a spell check. [This message has been edited by Monza76 (edited 08-15-2003).]
I know your talking about me and I KNOW I can't spell, I don't care! But I don't HAVE a word processor , that's why.
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08:05 AM
DjDraggin Member
Posts: 2854 From: St Louis, MO. USA Registered: Feb 2003
Raydar Here is a picture of the Impulse and a quote from the Isuzu spotters guide: The Impulse was introduced in the US market with little change from the Ace Of Clubs concept car. The addition of slightly larger bumpers to meet the 5 MPH DOT requirement, shortening of the windshield and lengthening of the hood to allow for easier installation of the engine on the assembly line, and enlarging the overall dimensions a few inches to allow more interior space in anticipation of sales in the US market being the only significant changes from the concept car. The Japanese market equivalent, the Piazza , became available in 1981, but crash testing and DOT certification delayed the vehicle's introduction in the US by several years. The 1983-84 models were all non-turbo 2.0 liter SOHC. Outwardly, these models lack any rear spoiler or front air dam. Distinguishing features of earlier model Impulses are the headlight eyebrows and plastic inlaid tailgate garnish. The standard 14x6 alloy wheel was the aluminum color tic-tac-toe style with twelve inlaid squares with black accent, arranged similarly to a tic-tac-toe pattern. Taken from: http://kourt.dehaas.com/vehicles/
Razor_Wing take DjDraggin's suggestion and try that program. No offense meant but sometimes it is hard to read.
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01:29 PM
jscott1 Member
Posts: 21676 From: Houston, TX , USA Registered: Dec 2001
Yeah. I'm confused, too. I just can't picture the early Impulse. Unless... Were the later ones the same car that shared a body and Chassis with the Geo Storm?
Yes, I had a 92 Geo Storm that was virtually identical to the Impulse of the day, (except it lacked the handling by Lotus badge ) GM was struggling in the early 90s to produce a small car and rebadged the Isuzus and Suzukis and whatever, as Geos.
I don't think it's a stretch that Lotus was involved in the Fiero suspension, but there is no documented proof of that.
------------------ If you find my advice useful, then please give me a positive rating, thanks... 1988 GT (Firebird Interior) 1988 Coupe (Daily Driver), 1985 SE (Project Car) Recent Addition 1985 Coupe (parts car) Firebird Interior Installation Thread
[This message has been edited by jscott1 (edited 08-15-2003).]
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03:08 PM
fierobear Member
Posts: 27109 From: Safe in the Carolinas Registered: Aug 2000
Its my understanding that the 88 suspension was not redesigned. But It was the original intention of the engineers to use that susp. from the start. The Pre88 suspension was used to cut costs.
I dont know how true this is, but it makes complete sense.
Its my understanding that the 88 suspension was not redesigned. But It was the original intention of the engineers to use that susp. from the start. The Pre88 suspension was used to cut costs.
I dont know how true this is, but it makes complete sense.
I have read this also. The susp upgrade would have increased the project's cost by 10% (30 million) so they were postponed.
That story is consistent with some of the articles written before the Fiero was introduced. Imagine if they hadn't been so cheap at GM we all would have the adventages of the 88 suspension and brakes.
Ira
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05:34 PM
Whuffo Member
Posts: 3000 From: San Jose, CA Registered: Jul 2003
That story is consistent with some of the articles written before the Fiero was introduced. Imagine if they hadn't been so cheap at GM we all would have the adventages of the 88 suspension and brakes.
Ira
Yes - but if they'd spent the extra money to get the suspension and some other things right (like that molded foam interior stuff), then the price of the car may have been so high that it wouldn't sell very well. As the Fiero was designed, warts and all, it sold amazingly well - which those of us who restore and love these cars appreciate 'cause it makes it relatively easy to find parts...
But it does make one wonder - if the Lotus-tuned Impulse uses the same basic components as our Fieros, Lotus-like handling should be attainable - right?
Whuffo, good point about the price. Many cars have achieved handling greatness with far less sophisticated suspension than the 1984-87 Fiero. The magic is in the details.
Ira
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07:43 PM
Razor_Wing Member
Posts: 1753 From: Blowing Rock, NC, USA Registered: Apr 2003
Its my understanding that the 88 suspension was not redesigned. But It was the original intention of the engineers to use that susp. from the start. The Pre88 suspension was used to cut costs.
I dont know how true this is, but it makes complete sense.
I'll third this statement. In the 88 suspension, there is, however, sligtly less bump steer, and they gave it vented brakes. But I've read that the "new" suspension was'nt nessarly for better Performance, and it makes sence. They started of thinking of canceling the fiero about 1/2 way through 87, so why would they redesighn it to be BETTER? They just wanted to save what money they could from the program!
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07:55 PM
Kento Member
Posts: 4218 From: Beautifull Winston Salem NC Registered: Jun 2003
Originally posted by Monza76: BTW a suggestion to the extreme "typing impaired", why don't you type up your responses in a word processor and then paste them into the forum message space, that way there would at least be a spell check.
hukdonfonixwerkedferme I kant mispel werds, I hav an eror corekting modam
------------------ 87 2M4 5 spd Daily Driver Project 2m$ **************************************** 86 SE Needs every thing but a Motor & Sunroof Seal!!! Now for Sale! $750.00 http://home.cfl.rr.com/fierose Web Master Central Florida Fieros http://www.centralfloridafieros.com
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07:56 PM
PFF
System Bot
Raydar Member
Posts: 41474 From: Carrollton GA. Out in the... country. Registered: Oct 1999
Raydar Here is a picture of the Impulse and a quote from the Isuzu spotters guide: <snip>
And that has what amounts to a Chevette suspension?! I never woulda guessed it. I drove a Chevette for about two days. (It was a rental.) One of the most uninspiring cars I ever drove. Always thought that generation of Impulse was a beautiful car. Still do, for that matter.
The problem with the Chevette was in the details, while Corollas were managing with MacPherson struts and leaf springs the Chevete had control arms front and a nice torque tube, trailing arm, panhard rod suspension rear (this is a fore runner in design to the last generation F-body). The problem was that GM in North America didn't really start to take small cars seriously until...., let me rephrase that GM in North America has never really taken small cars seriously.
The Opel Kadette and the Isuzu Impulse were both fine handling cars (not great but quite competent), the Opel was quite successful in rally and road course racing (and remember that was back when rally cars were far closer to stock in most classes).
As for the Impulse, the Ace of Clubs concept car from Italdesign (Guigiaro) was meant to be the next VW Scirocco (they did the original) but when VW decided to do their own design this time, Guigiaro went looking for a buyer and Isuzu stepped up. The design was changed to fit the RWD Chevette floorpan instead of the VW FWD and the Impulse was born. The later turbo models were fast for their time.
Ira
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11:47 PM
Whuffo Member
Posts: 3000 From: San Jose, CA Registered: Jul 2003
Details like the anemic BlueSmoke RodNocker engine, the ThinTin body with the pressed cardboard interior, etc. You'd never know if it handled well because it wouldn't go very fast and it took a while to get there. And let's not forget the famous ButtUgly styling - Fisher Body woudn't admit having anything to do with this one.
Under all that cheapness was a fairly well designed suspension system. Even in Fiero trim, the front suspension works pretty well. It's that rear suspension that needs some help...
When they took the front wheel drive system from the X car and grafted it in, someone was asleep at the drawing board when they fudged in hard mounts for the tie rods. If the center of rotation that the suspension pivots on was shared by the inner tie rod mount it wouldn't jump sideways like it does. I can make allowances for the unequal length drive axles, but that tie rod thing is an engineering botch.
No argument there, this system is used on quite a few cars without the "Fiero sidestep", however only the Ryanne/Held fix seems to have a real solution, by putting the toe link in the same plane as the control arm. The Held part looks like it would do the trick, but it "looks" a little complex and heavy, anyone know if it is much heavier than the stock parts (I am only concerned about the possible increase in unsprung weight).
Ira
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09:10 AM
Whuffo Member
Posts: 3000 From: San Jose, CA Registered: Jul 2003
No argument there, this system is used on quite a few cars without the "Fiero sidestep", however only the Ryanne/Held fix seems to have a real solution, by putting the toe link in the same plane as the control arm. The Held part looks like it would do the trick, but it "looks" a little complex and heavy, anyone know if it is much heavier than the stock parts (I am only concerned about the possible increase in unsprung weight).
Ira
I'll find out more when I get to the back end of my car; first, the front end gets the ground-up rebuild as soon as all the parts get here. Like you, I prefer to keep the unsprung weight to a minimum but I'd gladly give up a few ounces to correct that one flaw.
Imagine you're exiting the freeway, slowing down as you loop around the cloverleaf - nice sweeping turn - and suddenly the clown in front of you locks 'em up. You jab the brake pedal and...
Yow, I hate it when the car does that!
One thing I'm sure is going to happen when I get to the rear suspension is that the cradle bushings are going to be replaced with poly or aluminum - and the rear control arm bushings are going poly too. I'm sticking with OEM rubber all through the front (ask me why) but the back needs this treatment to reduce the ability of the cradle and rear suspension to steer the rear wheels. These little cars suffer from torque steer just like the front drive version but you don't feel it in the steering - instead, it causes the rear suspension and cradle to shift on the rubber bushings and you get that funny loose feeling in the back on acceleration. This is disconcerting...
However, the (i hate to call it) bumpsteer can be dangerous - hit a bump or make a sudden change in acceleration or braking while in a hard corner and you can lose control in the blink of an eye. This is dangerous...
I totally agree with your buildup plans Whuffo, I would also leave rubber up front and go with full poly rear (with aluminum cradle bushings). Part of what you are describibg is the drop throttle oversteer, not much you can do for that except stiff bushings and shocks, and wider rear tires. As a matter of fact that is the only change I would make to your plan, wider rear tires (two sizes should do it) I would like 195/65X15 front and 215/60X15 rear (I am not a big fan of ultra low profile tires, too many bad roads here). And make sure you use shocks with lots of jounce control (the stock struts have practically none, they catch the car on rebound).
I plan on doing the same thing when I get the money together.
Ira
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04:26 PM
Whuffo Member
Posts: 3000 From: San Jose, CA Registered: Jul 2003
I agree about the tires - in fact, I've already changed to 205/55-16 in the front and 225/50-16 in the back. These fit comfortably and work well on a Fiero. The shocks / struts will be Monroe Sensatracs; these give a decent ride yet still provide good damping.
OK, money is always a problem. The tires I described (Yokohama Avid V4) on nice Mille Miglia MM-11S 16x7 wheels were $658 mounted and balanced from TireRack. Not too bad, eh?
The entire front suspension including ball joints, shocks, and tie rod ends came to $302 at Rock Auto.
I'll let you know when I get to the rear end. I believe that its possible to make a correction to the geometry without too much trouble and fix that bump steer problem for good.
And your instincts about the larger tires on the rear are correct - since switching to these new tires I've found that when you push it hard it handles MUCH better. When the back end comes around under acceleration it does so gracefully and tucks back in easily.
Of course, I'm not building a race car. I'm building something for scenic drives and short trips that'll get me there and back swiftly and in comfort and safety - and do it reliably. The Fiero does most of this pretty well already, but I'm going to have to rework the "swift" and "reliable" parts a bit to get it right...
Whuffo, Those are basically my goals as well. If we ever organize an autocross event out here I may give it a try.
I still have serious suspension issues, however I already have the front shocks replaced (Monroes I think) and urethane end links in the sway bar, the rear struts (also Monroes) are sitting in boxes at my house, I need one upper front and one rear ball joint, and since the rear suspension will be apart, I may get the urethane control arm bushings. The cradle mounts will have to wait.
I may get the moog caster kit for the upper front arms (the long mounting bolt, and all of the shims) so that I can dial in more caster but I don't plan to add a rear sway bar just yet. Let me know what you are planning and give me a rundown of the results.
Ira
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11:47 PM
Aug 17th, 2003
Whuffo Member
Posts: 3000 From: San Jose, CA Registered: Jul 2003
Ira, start with those ball joints - Rock Auto (www.rockauto.com) has the best prices I found on Moog parts. As long as your control arm bushings and ball joints are good, you probably won't need the caster kit unless something's bent. Even if you do, all you'll really need are the washers; you can probably find suitable replacements at your local hardware store.
Those front upper ball joints are easy enough to change and a failure here on the road would SPOIL YOUR DAY in a bad, BAD way. Replace in pairs; if one's gone the other isn't far behind.
Here's the way the ball joint crumbles: rubber seals lose their integrity and water gets inside. The ball and socket get a little rusty and pitted - this is when you start hearing noises and the steering starts getting a little stiff. These rough surfaces move as the suspension flexes and the ball wears into the socket. It doesn't take too much of this before the ball breaks through the back of the socket - and when this happens the steering instantly locks up.
Hope I got the message across firmly enough; if you think the joint is bad, change it NOW.
Did you remember to get the cam bolts to go with those struts? If not, do so - they're worth every penny.
May as well put the poly bushings in while it's apart; they're cheap in comparison to some of the other parts (priced a rear ball joint yet? eek!). And if aluminum cradle bushings are out of reach, consider putting poly in there too. You may find that you don't need aluminum there - a little give is a good thing. And when you price the parts and discover that the rear lower ball joint is unique to the Fiero and priced accordingly - check the price of the rear wheel bearings and be glad you don't need those too...
[This message has been edited by Whuffo (edited 08-17-2003).]
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12:54 AM
RBeaubien Member
Posts: 775 From: Glendale (Phoenix), AZ, USA Registered: Mar 2002
Everyone give thinks the Chevette was sh*t. It wasn't too bad and had its place in the market. I had a '77 for my first car when I was 16 (1981). It had 68k miles on it at the time. I beat that car to death as most teenagers do and traded it in with 225k on it for my NEW '86 Fiero SE 4-speed in May 86. At the time, the stereo in the car was worth more than the car, but it had served me well. Cheap, reliable, easy to maintain transportation.
Whuffo, The ball joints will be replaced soon, I realize the danger. I may have to settle for the joints that NAPA carries. As for the rear, I may go with the poly bushings for the control arms and leave the rubber in the cradle for now (not as much flex there as in those huge control arm bushings).
Ira
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07:45 AM
Will Member
Posts: 14303 From: Where you least expect me Registered: Jun 2000
Which kind of upper ball joints still use castle nuts?
All the upper ball joints I've seen use nylon lock nuts, which are a hue PITA in that application. I haven't checked TRW units yet, but the others I asked about all had nylon lock nuts.
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12:23 PM
Whuffo Member
Posts: 3000 From: San Jose, CA Registered: Jul 2003
Whuffo, The ball joints will be replaced soon, I realize the danger. I may have to settle for the joints that NAPA carries. As for the rear, I may go with the poly bushings for the control arms and leave the rubber in the cradle for now (not as much flex there as in those huge control arm bushings).
Ira
I don't know if Rock Auto (www.rockauto.com) ships to Canada - but if they do, their prices are much lower than NAPA's.
And try to save up a few extra dollars before beginning - when you start taking things apart you may find that some parts you weren't planning to change are worn out or broken. Don't forget the cam bolts for the struts - it's almost impossible to set the alignment without them and you have to buy them separately...
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01:52 PM
Whuffo Member
Posts: 3000 From: San Jose, CA Registered: Jul 2003
Which kind of upper ball joints still use castle nuts?
All the upper ball joints I've seen use nylon lock nuts, which are a hue PITA in that application. I haven't checked TRW units yet, but the others I asked about all had nylon lock nuts.
You can buy castle nuts at Home Depot (in the hardware department) if you need them; the studs are still pierced for the cotter pins even though the nylon lock nut is used.
Nylon's not a bad idea here, though. That joint is under compression at all times; the only time the nut may carry any load at all is when you jack the car up. And when time comes to take things back apart, I'd rather just burn the nylon nut off than fight with a rusted castle nut.
Originally posted by Whuffo: the studs are still pierced for the cotter pins even though the nylon lock nut is used.
Not the ones I've gotten.
quote
Nylon's not a bad idea here, though.
Obviously you've never used a nylon nut in this application. Trust me, you don't want to. There are flats on the shank for tightening the nut down. Since you have to hold the shank with a wrench, you can't use a socket on the nut. Because of the proximity of suspension components you can't even get 1/6 turn at a time. You have to flip the wrench over every stroke. I'm into my suspension often enough that I need a ball joint that's easy to remove and reinstall. When I was reinstalling it the first time, I broke a jaw off the wrench I was using to hold the shank.
Overall, nylon lock nuts are a gross inconvenience in this application, and I'd like to strangle the guy who came up with that idea.
[This message has been edited by Will (edited 08-17-2003).]
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08:35 PM
Whuffo Member
Posts: 3000 From: San Jose, CA Registered: Jul 2003
Obviously you've never used a nylon nut in this application. Trust me, you don't want to. There are flats on the shank for tightening the nut down. Since you have to hold the shank with a wrench, you can't use a socket on the nut. Because of the proximity of suspension components you can't even get 1/6 turn at a time. You have to flip the wrench over every stroke. I'm into my suspension often enough that I need a ball joint that's easy to remove and reinstall. When I was reinstalling it the first time, I broke a jaw off the wrench I was using to hold the shank.
Overall, nylon lock nuts are a gross inconvenience in this application, and I'd like to strangle the guy who came up with that idea.
So how would a castle nut be easier? It's still just as "easy" to get a wrench on it. And the crennelations in the nut are perfect rust traps; maybe you break things down often enough that it's not a problem for you. For us average folks, that 10 year old castle nut needs a torch to get it off...
OK - you can get ratcheting box end wrenches; Sears has them and I'm sure other do too. Try one of those on the nut and this task will go much quicker.
I'll keep an eye open for joints with castle nuts and let you know if I find any...
[This message has been edited by Whuffo (edited 08-17-2003).]
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08:44 PM
Aug 18th, 2003
Will Member
Posts: 14303 From: Where you least expect me Registered: Jun 2000
So how would a castle nut be easier? It's still just as "easy" to get a wrench on it. And the crennelations in the nut are perfect rust traps; maybe you break things down often enough that it's not a problem for you. For us average folks, that 10 year old castle nut needs a torch to get it off...
OK - you can get ratcheting box end wrenches; Sears has them and I'm sure other do too. Try one of those on the nut and this task will go much quicker.
I'll keep an eye open for joints with castle nuts and let you know if I find any...
My point is that I can run a castle nut all the way down with my fingers in about 3 seconds (well, maybe 4). When I was reassembling my front end, not counting the time breaking the jaw off my 8 mm wrench cost me, just running the nut down to the point where it started to get tight took several minutes. At 1/12 turn each time you put the wrench on it, it's slow and tedious when there's absolutley no dam reason for it to be. It just pisses me off that people depart from the time tested very functional normal way of doing things and cause me grief and inconvnience just so they can save $0.07 per ball joint by using a nylon nut.
I've never needed a (quite expensive) ratcheting box end to do this job before. Why the heck do I need to go buy one now? Like I said, I'd like to strangle the guy who came up with that idea.
I've never had a problem getting a castle nut off, even an old one. They're typically covered in grease from the ball joints anyway, so rust is seldom an issue.
[This message has been edited by Will (edited 08-18-2003).]
. And I 2nd the fact of the 88 spension being desighned by lotus 100% false. This has been said by GM AND Lotus, as well as the engineers that DID the redesighning.
and I KNOW I can't spell, I don't care! But I don't HAVE a word processor 
) GM was struggling in the early 90s to produce a small car and rebadged the Isuzus and Suzukis and whatever, as Geos. 
