6G Celicas Forums

I recently bought an e46 328i, which is now my daily, and decided to store my 95 ST. I did maintenance and suspension work to the 328, and was struck by how much more expensive (needlessly I believe) BMW parts are than Toyota. And I have to say, for as much love as the e46 chassis gets, I honestly feel like the AT200 is the better car to drive.

Anyway, since storing the Celi, I've been constantly thinking about a project for it (and missing its excellent fuel economy), and I was looking for some input. I should say, though, that I wouldn't likely get started on any such project for at least a year from now, likely longer.

So the philosophy of the build would be to maintain the reliability and fuel economy of the 7a, while increasing long distance driving comfort and maximizing engine power delivery through driveline and suspension improvements. Basically, in the same vein that the BRZ/FRS was designed to make the most out of a relatively low powered engine through intelligent overall car design. The emphasis is on a comfortable, fuel efficient and reliable car for driving long distances, while always having the potential to be a 'driver's' car.

I have a few ideas currently, such as:

-Lightweight driveline components, wherever possible. Are these available for the 7a? I see flywheels for the GT, but so far nothing for ST.
-Underdrive pulleys
-Lightweight wheels/ sticky tires.
-Weight reduction where possible, but not in compromising comfort or increasing road noise. Feasible?
-Lightweight exhaust
-4 wheel disc brake conversion
-Suspension upgrades. Would certainly welcome suggestions on this.
-Cooling system upgrades (better efficiency)

And more, but I'll leave it at that for now. Other than additional comments, I'd also like to know if anyone has suggestions on where to look for parts? I've done a fair bit of searching and referenced a few sticky's, but it's still hard to find parts for an ST. For 7a specific parts, I suppose I can look at Corolla sources, but for suspension and other parts I'm at a loss.

Finally, I've been wondering if it would be possible to swap a 7a into a GT body? I assume yes. I feel like the GT is more amenable to performance suspension and braking mods.

Any input is very welcome, thank you for reading!

This post has been edited by senick: Feb 23, 2017 - 9:25 AM

For comfort, I would start off with stripping the interior and adding soundproofing wherever possible. That might add a bit of weight but is totally worth it to be comfortable.

struts, I would just stick with KYB and whatever springs you want. coilovers aren't as comfy.

brakes, wouldn't be too hard to swap the gt brakes into the rears. just gotta source all the parts.

the difference between GT and ST isn't much. aside from the 5sfe and rear disc brakes, it's almost the same.
suspension isn't any different. struts and springs from a GT will fit an ST and vice versa. even if you found a GT, the stock suspension on it would probably need replacing anyways so you're still ending up in the same place.

the 7a is reliable as F***, just keep up on maintenance and it should run forever.

Awesome, thank you for the input.

Good to know the ST and GT are the same suspension-wise, that will help greatly in finding parts. I know that as far as suspension goes, there is always a trade-off between comfort and performance, and my priority is towards comfort, so you're probably right with the KYB's.

As far as interior goes, are there lighter and more comfortable alternatives to stock seats?

After looking around, I'm starting to entertain the idea of having parts fabricated since there's an understandable lack of performance products for the 7a drivetrain. I'm looking to reduce unsprung weight as much as possible, as well as anything that rotates. I've started looking up companies that fabricate carbon fiber axles, but I wonder if that would be worth the cost... Any aluminum options?

I have 7th gen seats in mine and just holding them you can feel they are much lighter than the stock seats, but with the reduced weight also comes reduced comfort. there is less "hug" with these seats and less cushion so your butt will hurt on a long drive. haha. but the 7th gen rear seats bolt right in as well and are fairly light if you don't care about passengers lol. I've never weighed them aside from holding them in my hands though. I think the stock seats are a great mix of comfort/weight/looks. I just changed mine out because i hated tan seats.

as far as everything else, pulleys and cf axles, I've never really looked into those so I'm not sure either. let us know what you can find.

Those seats are nice, and I love the direct fit. I'd certainly remove the rear seats completely; nobody I know is small enough to fit in them anyway.

Question on radiators:

What are the benefits of upgrading to a higher spec radiator? I can see if it is required for track use where extra cooling is needed for the extra engine loads, but if driving the car in normal situations, is there a tangible reason to upgrade (other than the weight savings)?

What I'm wondering is if it will ultimately increase fuel economy or not. Performance radiators claim to allow the engine to run at cooler temperatures, but weren't the stock radiators designed to let the engine run at an ideal temperature in the first place?

EDIT:

After doing some research, I don't think a performance radiator would help fuel economy, and could actually hurt it. If the computer senses that the engine is running at a temperature lower than default, it may compensate by making the AFR more rich in an attempt to bring temperature up. Probably best to stick with stock on this one I'd imagine.

This post has been edited by senick: Feb 23, 2017 - 2:19 PM

I recommend changing the whole braking system, fronts and rears and prop valve, to GT parts. Well worth it.

The 6th gen seats are so good though, so very good. They really don't weigh too much, can't foresee them weighing too much more than any other factory seat that's all manual operation anyway. I had a ST myself, the only thing that was really done to it was Tein S. Tech springs and KYB struts and then did a short throw before it was sold but it was a nice car. If I bought another ST this is what I'd do:
GT brake conversion with Centric StopTech Sport slotted rotors(only because blanks aren't offered) and StopTech Sport pads, flush and fill system with Castrol DOT 4
Lightweight alloy 16x8 rims wrapped in performance summer tires
Short shifter
KYB struts with Tein S. Tech springs, or possibly some kind of coil-over set
Lightweight flywheel if reputable option available
As high a quality header as possible then matching diameter exhaust from there back with a high flow cat(I can't stand raw exhaust) and Jones MaxFlow straight through muffler
True cold air intake using AEM filter or like, so filter into the fender or bumper and not just there in the engine bay
Sway bars, Suspension Techniques? or other
Poly bushings throughout suspension as well as poly motor and trans mounts

I think that more or less covers it. Could do stuff like a carbon hood or lift but you get into the land of really diminishing returns.

scroll to the bottom

http://www.6gc.net/forums/index.php?showto...49858&st=80

Excellent input all.


Does this have a negative impact on ride comfort?

Also, you mentioned headers, which I agree with. I've heard it's a good idea to advance ignition timing after installing them. Thoughts?

BonzaiCelica, that's an awesome list...can't believe I've never seen it before in the forums.

Two more questions though:

Is there any potential benefit of a port and polish for the 7a head? I've heard it doesn't really matter given the design of the head, but I have to imagine it would at least do something.

How much returns could one expect to gain by trying to mess with the weight distribution of the car? Or, maybe put another way, are there potential drawbacks of removing too much weight in one particular location?

This post has been edited by senick: Feb 24, 2017 - 8:59 AM

There was one bushing people swapped to poly that made a more negative impact than what it should and I'm trying to remember which one, I think Richee was one that tried them. Outside of that it'll ride somewhat firmer but you also remove play and slop in the suspension, it's what I'd do but if you're wanting to maintain ride comfort you may want to do it last and then only certain bushings.

Advancing timing is recommended after doing the header and exhaust and you're just in luck since only OBDI cars can do such. As far as port and polishing goes if it's something you can do by yourself then sure, but I certainly wouldn't pay for it to be done. Any weight you can move off the front and/or to the rear would help, but beyond a battery relocation and carbon hood you start getting into things like A/C removal and that's just silly.

This post has been edited by Box: Feb 24, 2017 - 3:46 PM

Not the motor mounts right? That would be a big priority of mine, as in my experience the 7a tends to shake a lot at idle. What are the best motor/transmission mounts?

Also, is there such a thing as functional aero for the 6gc? I'd probably end up removing the spoiler, assuming that it only increases drag and does little to improve handling.

Endlink bushings maybe, for some reason that sounds right. I don't recall my 7A shaking much at idle, ran fairly smooth for an inline four. The best mounts are subjective, poly will transmit more vibration into the car but it'll reduce deflection under torque.

The spoiler only increased drag by .01 if I recall correctly, can't recall how many pounds of downforce it added though. I like the '94-95 spoiler, the '96-99 I'd want to remove though. There are a few lip kits that in theory would reduce the the amount of air that gets under the car.

This post has been edited by Box: Feb 24, 2017 - 8:21 PM

Yeah, my motor mounts were probably just shot, that's why I would get shaking at idle. I guess some of that is just inevitable from an inline 4 though.

So I've also been thinking about engine internals. I'd love to have the 7a rebuilt with OEM parts, but are there slightly better options available? The big objective would be to reduce inertial resistance in the engine, but I'd be concerned about compromising reliability. I've heard only good things about Wiseco pistons. If anyone has experience with lighter than stock pistons, I'd love to hear about it to see if it would be worth exploring further. I want to keep stock compression, so may not be worth changing?

Also, I hear the 7a's power is inherently limited by the restrictions in the head design. That being the case, would any exploration into throttle body upgrades be viable, or ultimately useless?

This post has been edited by senick: Feb 25, 2017 - 12:33 PM

If you want rubber mounts it'd be worth looking into getting O.E. replacements from the dealer, but given the age they'll have to be ordered if they can even be gotten anymore.

Toyota engines have the FE or GE designation, FE meaning economy and GE meaning performance. Really it boils down to valve angle being the primary difference, narrow for FE and wide for GE. As far as performance on the 7A goes I'd do a port and polish on the head myself and then shave it some to bump compression up a point on top of doing the header and exhaust as well as timing advancement, will probably have to use 89 or 91 instead of 87 but it should give a small increase in performance. From what I can gather the Russian 7A with 9.5:1 compression and more or less header back exhaust put out 120 hp, so a little bit better than the standard North American fare. Of course there's also turbocharging which would be the easiest way of adding decent power.

If I had a stock ST and I wanted to keep the reliability and gas mileage, I would do a 4age 20v swap (black or silver top). I would then get a standalone ECU and get it tuned to suck a little more power out of the engine. I hear a lot of great things about the 4age 20v. The major problems I hear is that you have to rev the s**t out of it to get into the good power band. I remember reading about someone on these forums putting a 4age 20v in a ST and getting 36 mpg, couple that with 160 hp (to the crank) and that will give the ST the kick in the pants it needs. From there I would do the coil over and tire upgrades to get the car handling well. That would be my ideal ST build (this is making my mouth water, maybe I should pick up a ST).

This would work with the stock ECU?


Yes, I've been pondering the ol' 7age route, but I have my concerns about compromising reliability. Ideally I'd stick with the stock ECU, mostly because I don't know any trustworthy tuning shops in my area, and certainly don't have the experience to do it myself.

Also, I've been doing some reading on transmission swaps, but the information I'm seeing is inconclusive. The idea of putting a c60 in sounds a bit appealing, given the extra gear for highway driving. But it seems like it's still an open debate as to whether the 6 speed helps fuel economy over the 5 speed in the 7a, given that the 7a might not have enough power to make the most of the extra gear. The topic I was reading kind of left me hanging in terms of getting an answer.

If it were me, in order to not compromise reliability, I would do a 4age swap not just a head swap. It is like when I was thinking of doing a 5sgte instead of a 3sgte, it sounds great to have the extra displacement but then you have a Frankenstein motor that may not be reliable. Yea, you lose some displacement in the swap but you still net more power, a higher redline, and you keep the Toyota reliability. Plus if you get a set of aftermarket camshafts you can get more power out of the motor and still keep it NA.

This post has been edited by HardHead93: Feb 26, 2017 - 5:53 PM

^ Yeah, I realize now that I misread your initial post. I've been reading so much about the 7a-ge lately that my mind just assumed that's what you meant.

Swapping in the whole 4age seems like the better option than mixing the two engines for sure. Finding a black top would be tough though, and probably not cheap. VVT would be fun, however... and if fuel economy is that good... I have some thinking to do.

Would have to look into it but I don't see where an extra point and increasing flow and timing would warrant a reflash or piggyback even having MAP instead of MAF, but would have to look more in depth since it's been yeas now since I've looked into it. The 6 speed is so close together you really won't get any mileage difference, same with the 5 and 6 speed in the Miata. 4A-GE with standalone as mentioned would be another option, I think some have done the 4A-GZE in 7A Corollas before and maybe a Celica. The 20V you do have to rev out to get going from what I've read, but you have to do that to some extent with the 7A anyway. Anyhow here are the ratios for the C56 and C60 respectively:
1st: 3.166
2nd: 1.904
3rd: 1.392
4th: 1.031
5th: 0.815
Reverse: 3.250
Final: 4.312

1st: 3.166
2nd: 2.050
3rd: 1.481
4th: 1.166
5th: 0.916
6th: 0.725
Reverse: 3.250
Final: 4.529

So at 70 mph you're talking about 3,400 rpm with the C56 vs 3,200 rpm with the C60, hardly worth the trouble in pursuit of fuel saving.

Very true, but there is a difference:
4A (Black top): 165 PS (121 kW) at 7,800 rpm with 16.5 kg·m (162 N·m) of torque at 5,600 rpm
7A (1995) : 110 hp (82 kW) at 5600 rpm and 115 lb·ft (156 N·m) at 2800 rpm

At least with the 7A torque peaks at a reasonable RPM, and really isn't that much less than the black top (assuming I could even find one). At this point I think it's more or less subjective. Both engines are reliable and efficient, but how one defines 'fun' or 'engaging' is just preference on where the torque comes in. Hitting 'power' (such as it is in the 7a) midway through the rev range to me is much more engaging than dragging it out to redline and constantly trying to keep it there.

Also, thank you for the gearing breakdown, that's very helpful to see it displayed in a comparative way like that. If a 6 speed wouldn't get any better MPG then, may not be worth the trouble.

This post has been edited by senick: Feb 26, 2017 - 10:26 PM