Ok, first of all, I realize this is a somewhat n00bish kind of post, but I've read and searched around and it's hard to find any kind of consensus on this, so here goes.

I just recently (barely over a week ago) bought my '98 Sunfire GT with the 2.4 motor (5 speed, by the way). It has a little over 91,000 miles on it which I realise, especially for the year, isn't that high of mileage. The engine seems to me to run very well (then again I have zero experience with this engine to compare it to). In the usual juvenile sorts of tests, it has seemed to have plenty of power still (I can bark 'em good from a dead stop and powershifting to 2nd, which I've done like once just for sh!ts and giggles, I got another good chirp out of them too...and that was totally stock. An eBay intake seems to have added a nice little gain itself as well). I do have noise coming from the tensioner but I gather that's not uncommon and doesn't really affect performance (but sure sounds like crap).

A bit of background. Obviously I want to get more power from the car. I'm not the type of person who picks a number out of the air and shoots after that at all costs, I really couldn't care less if I'm making 150, 250, 300, or 400 whp, as long as I'm enjoying the car. Plus, the car is my daily driver and a crazy high HP number would probably make it a lot less streetable as well (not to mention cost a fortune). I've always been interested in drag racing but have never made a single pass at a dragstrip...I am, however, very interested in autocross, but again have only ever gone once (I do plan to go several times this summer though).

So...supercharged, or N/A? That's what I'm trying to decide between. My biggest question, how many horror stories are there of boosting older 2.4's and then blowing them up without a rebuild first? I know a lot depends on just how the engine has been treated and of course that's an unknown. I changed the oil a few days back and it was black as tar but didn't seem to have any kind of sludge or anything in it. Not sure what kind of oil was even in there before, but it has Mobil 1 10w-30 in there now and it seems to love it. A compression test would probably go a long ways towards determining just how healthy she is, and I may pick up a tester in the near future and check it, along with changing the plugs just for the heck of it.

My thought is, if it's pretty likely that a rebuild would be necessary (or at least reccommended), why not just go with an all-motor setup? The Import Performance Parts engine rebuild kit with 10.5:1 compression pistons and some good cams (probably oversized valves and stiffer springs too), plus all the basic bolt ons (including HO manifold swap and all), and it seems that I'd be pushing close to 200 whp, or a bit more, from what I've seen - a comparable number to what I'd get with the supercharger. Obviously it will cost more to go the all-motor route, but in the end it won't if supercharging it will likely just lead to the necessity of a rebuild anyways. On the other hand supercharging it would allow me to swap pulleys down the road and increase power if/when I get more power hungry.

Another cavaeat - how much power does the Isuzu tranny hold up to? I'm sure it's been discussed but I haven't really come across it, then again I also haven't really looked too hard for that. Obviously when power levels really start to rise I'll be needing a new clutch and probably will upgrade to a lightweight flywheel as well - but does this tranny like to take a crap at a fairly low power level? I'm not considering swapping the tranny at ANY point, just wondering if I might be wise to plan to keep it a bit under control to keep from turning the tranny into scrap (i.e. being satisfied with the lower limits of power that the all-motor build would provide).

Thoughts/input? Before someone mentions it, I'm aware that any of these kinds of mods will put me in street mod class for autocross...that doesn't bother me. I know I probably will never be competitive there, but I really just do it for the fun of it. Besides, driver skill is the #1 most important thing in any class, so if I can upgrade the driver mod enough, who knows what I could do. Sorry about the novel.

Sounds like you have done your research, very nice I can't say that with alot of new J-Tuners to the .org. 91k miles huh? That is pretty good in my book since my 97 Z24 with the 2.4 LD9 is pushing close to 140k miles on it and still running strong. I would say run a compression test, that would be wise to do before doing any modifications. I'm not sure what kind of budget your on but if you are more interested in AutoX than the 1/4th I personaly would stay N/A. Your not going to be going fast enough in auto X to really use the full powerband of a S/C or Turbo system. Go with a real nice suspension like:

Koni Yellow Struts
Ground Control Coilovers
front and rear tower strut bars
sway bars
all the motor mounts
all the bushings
short shifter
nice set or rims and tires
light weight flywheel
upgraded clutch

That is what I would start off with because you can NEVER be to safe in these cars. One thing people keep forgetting is that these cars were not built to race or perform the way it is needed for auto X. So safety first with the mods listed up above. After that I would then start the engine upgrades I'll throw out a nice setup that would work great in auto X and possible high 14's low 15's passes at the dragstrip with a nice driver.

2.3 HO Intake Manifold
56mm or bigger throttle body
"Secret Cams" (see sticky above)
WAI with a nice K&N Filter
either stock size lightened or underdriven pulleys depends if you want a powerful stereo system or not. If you want to get a little bit more extream with your NA setup there is alway the 086 head swap, with the 2.3 HO exhaust manifold, .20 bore 9.1:1 CR pistons, cometic head gasket (Now that there is one for this swap.)
2.5"-3" exhaust system. and HP Tuners for a real nice tune. With all that you are looking around the 210-220whp range NA. Hope this helped you and good luck in the future.





In the planning stage for an all American TRD Cavalier.

Z24HO - thanks for the pointers! And honestly, I'm not totally new here, I've been a member for almost 2 years because my ex-wife has an '02 2200 Sunfire and I joined to research for her car. Along the way I've picked up some things about the 2.4 as well, and now I have one. Plus I've been modding an '01 Eclipse Spyder GT for 2 1/2 years and while the parts are totally different, the concepts are much the same - do your research, have a plan, etc.

First off, as far as my budget goes, at this point I don't have much money to really throw around. I'm thinking basic bolt ons this summer as far as power adders (already got an intake, thinking full exhaust and that's pretty much it, and then hopefully HP Tuners shortly thereafter), but really (oddly enough) my focus for this summer was to get the handling of the car buttoned down...isn't it ironic that I was thinking that and you suggested it first? While not 100% positive on everything, I'm thinking slightly different parts in a few cases, but pretty similar to what you listed - I already have front and rear eBay strut tower bars (probably not the best but it seems they'll work). I'm planning to go with a AGX-Tein S-Tech combo instead of the Yellows/GC's although I considered them too. Really the only reason I'm leaning away from coilovers is because I figure I'd set them at one height and then leave them there permanently...and it just doesn't seem like an efficient use of money. I plan to add a rear sway bar as well, plus Powerslot front rotors, Hawk pads, and stainless brake lines. Also a nice set of reasonably lightweight 17" wheels and probably some Fuzion ZRi or other comparable cost summer performance rubber. Don't know how soon I'll have money to have a clutch/flywheel combo installed but that's probably after the other suspension mods.

As far as the power-adding mods you've listed, sounds sorta like what I was thinking for an NA build. I'd read about them, but I wasn't sure if the secret cams would be adequate for higher HP numbers or if I'd want to consider something more aggressive (like the JBP Stage 2 or something like that). 2.5" full exhaust is planned - not so sure about a 3" full exhaust as the car is a daily driver and I don't want the bottom end to start to disappear. As far as pulleys I take it they tend to work well on this engine (with my Eclipse pulleys were pretty much a joke, people who tried them ended up fed up with getting no gain other than the wonderful "service engine" light), and I really don't plan to do much (if anything) to the stereo - the stock one actually is pretty decent and probably good enough for my needs...and I'm a music lover too. A HO intake manifold and larger throttle body were also things I'd considered.

I was considering porting and polishing my own head and building it with cams and oversized valves, etc, although that may be too big of an undertaking for me (I have a dremel...I'd be working for hours on the head...). I'm not sure - I don't know hardly anything about building something like that but I'd be willing to learn if I could figure out where to look for info on such a project. Maybe someone has done a write-up on building their own head and I haven't seen it? As far as the head swap goes I don't have a very good grasp on what that entails but perhaps that's a possibility. With the head swap you can't use a header made for the 2.4 though, correct (since the exhaust ports on that head are different than those on the 2.4)?

With the 086 head your right you can't use a 2.4 header, and it kind of sucks that nobody makes a 2.3 header yet. But I do know that the 2.4 exhaust manifold out flows any 2.4 header on the market. Infact from what I have learned the 2.4 headers are really not all that much better than the stock manifold. But if you really wanted to use a header with the 086 head it would not be hard to have the flange from a 2.3 HO exhaust manifold fitted and welded onto the 2.4 header of your choice. With the head swap itself I find that it is about the same price if not a tiny bit more expensive to do the 086 head swap vs building up your current head. The only thing you really need to do with the 086 head is bore out the water passage to match that of the LD9 block, and now that Cometic makes a head gasket for the swap that makes it much easier. In the end you would have a CR of something like 11.5:1 so it would be smart to change your pistons and get something like the 9.1:1 .20 overbore weisco pistons from Karo on www.carcustoms.net, and get the thicker cometic head gasket. I beleive that would drop you down around 10.5:1 I can't remember off the top of my head I'm sure you can find it in the forums somewhere.






In the planning stage for an all American TRD Cavalier.

Well as you have said do a compression check, and a leak down test. Also I would replace the timing chain tensioner if it is making noise. Yes a common problem, but not one to leave be. I also would say for Auto X to go all motor. Unless the motor has signs of serious problems I would stay with the current motor and add bolt ons. Intake, Throttle body, header, exhaust, mounts, maybe some cams, suspension for autoX, and some HPT tuning on the dyno. I think that will give you plenty of power and fun for the autoX. Also would recommend a oil pressure gauge and oil temp gauge. If you were to stay with the current motor maybe a oil pump change to a melling pump.

Another option with all motor would be to get a 2000+ 2.4 with lower miles and put in. This can be done and just stock for stock seem to be a little stronger (which some will say no difference).



FU Tuning

Sorry I wish there was an edit, I meant to say the 2.3HO exhaust manifold outflows all 2.4 headers and exhaust manifolds.




In the planning stage for an all American TRD Cavalier.

Since I've owned both a '96 Sunfire with a LD9, and a 2000 Sunfire with an LD9 - I know that both feel equally strong. The '96 -'98 LD9 motors have a slightly lower CR than the '99-'02 LD9's have. But you can't really feel any difference(at least i can't). GM does rate the 96-98 LD9's any less than the '99-'02 LD9, although there may be about a 5 hp difference.

With either you have some options - depending on what you want.

1.) All- Motor "stock" LD9 - basically stuff like Perf cams, P&p the head & intake manifold, Perf pistons, Enlarge TB, 4-1 Header, Perf Cat, Cat back exhaust - with little or no Quad 4 parts.

2.) All-Motor hybrid LD9 - basically stock block, crank and pistons of the LD9, with Quad 4 (possible HO) head, Cams, valves, & springs.

3.) All Motor - 2.6L "Stroker" LD9 crank with a Quad 4 block.

4.) Supecharged - either the GM S/C or a centrifuge S/C.

5.) Turbocharged

6.) Motor build up with Nitrous Oxide.

It's kind of up to you want

Quote:

Since I've owned both a '96 Sunfire with a LD9, and a 2000 Sunfire with an LD9 - I know that both feel equally strong. The '96 -'98 LD9 motors have a slightly lower CR than the '99-'02 LD9's have. But you can't really feel any difference(at least i can't). GM does rate the 96-98 LD9's any less than the '99-'02 LD9, although there may be about a 5 hp difference.

I had a 97 Z24 5 speed, and traded it in on my 2001 Z24 5 speed. I can tell the difference (of course tranny's and ratio's are different as well). I have also swapped in 2000+ LD9's into pre 2000 cars they always seem to be stronger with the 2000+ motor. Also most of your N/A LD9's with strong times seem to be 2000+ cars, or at least motors. Throw out the 2000+ might or might not be stronger fact and still a 2000+ motor is going to have less miles and easier to find in good shape.



FU Tuning

Still with the 2000+ LD9 motor is easier to install the GM Supercharger on it. Although not impossible for the '98.

As for my two Sunfire GT's both had about 40-45,000 miles on them when I first got them, but then both are automatics - which may be why I couldn't really feel a difference. Since both cars have the basically the same motor, the same transmission, and the same gear ratio.

Quote:

I can tell the difference (of course tranny's and ratio's are different as well).

Well the different tranny & gear ratios explains why they're a bit faster. So it not the motor he needs to swap - but the tranny & gears.

Quote:

Throw out the 2000+ might or might not be stronger fact and still a 2000+ motor is going to have less miles and easier to find in good shape.

My 2000 Sunfire GT has almost 85,000 miles on it - which is actually slightly below mileage. And is only about 6,000 miles less than his '98 GT has on it.

Personally since your motor appears to be in good shape, and low mileage for it's age. I would say keep it - spend to money you would on a motor swap, on performance parts for your motor instead. You'll likely enjoy it more.

Quote:

Personally since your motor appears to be in good shape, and low mileage for it's age. I would say keep it - spend to money you would on a motor swap, on performance parts for your motor instead. You'll likely enjoy it more.

I do agree with this as well. I was giving options. Truth is you can find a 2.4 with much less miles than he has on his current one.



FU Tuning

Wow...thanks for the input guys - it's nice to see some discussion and such generated by this.

kj1168 - Yeah, I'm pretty much trying to decide between #2 and #4 on your list - if the secret cams would be sufficient for a decent all motor 2.4 build then I would definitely rather go that route because even buying the parts new from GM (which obviously is the most expensive way to go), it would still be cheaper than the JBP cams. Supercharging the car seems to be the better way to go if you want an "easy" solution (easy in quotes, because adding boost to a NA car is always a challenge no matter what kit is available, and my car being a '98 instead of a 2000+ would make it a bit more challenging then at that. I don't think nitrous would really be too useful in autocross...I probably won't ever get really big into drag racing, where it would be a much bigger benefit. And I'm definitely not one of those ricer street racers that would be out spraying all over the city streets - not to say I'm not prone to a stoplight showdown here and there but I don't make a habit of it and I am *very* selective about the situations where I do in fact do it. But that's for a different discussion. I am somewhat interested in nitrous though honestly and perhaps if I did get into heading to a test and tune just for the heck of it every week or so, a nitrous kit might be nice. Honestly if I got into an engine rebuild, a good all motor setup would lend itself very well to spraying now and then at the track - a well tuned 75 shot with a nice solid all motor build would probably make close to if not 300 whp or so. That would be more than enough to break 'em loose at the strip, that's for sure.

One of the original questions I had I haven't really seen discussed, and that's how common it is for people to have something blow up with the supercharger. I realize that lower boost levels are the norm for the supercharger (and the higher ones are generally reserved for the turbo guys), but these engines aren't getting any newer and adding boost in any amount to an engine does nothing but make it more likely to have something go *pop*. I see very few people, it seems, who have added boost to any motor and haven't done a rebuild - which is why I'm thinking I may as well just go with the all motor route and plan on doing a higher compression rebuild after things like the head, secret cams, HO intake manifold, and the usual I/H/E. Sure I'm limiting myself in terms of how much power I can make but I think that realistically that may be enough power for what I want. As long as a 200-225 whp range all motor 2.4 is still going to be streetable - I don't want to have to constantly take the engine to 5000 RPMs just to have any kind of power for daily driving. I don't think it seems that's the case though.

Plus, if I didn't for a high compression rebuild after doing everything else possible, I could still supercharge the car with no adverse effects. I would have spent money that I didn't need to spend but it would still help get more power with the supercharger as well.

I still think with what you want you want to do I would go with a high CR NA build with the 086 head. When it is time for a rebuild go with forged internals, make the engine bullet proof and then intall a 75 wet shot or higher. That would be plenty of fun, and what I would love to do. Right now I'm waiting to have the money to buy the pulleys I want. I don't look like MD is going to have his stock pulleys made any time soon so I think I'm going to have to do the Unorthodox UD pulley with the AEM alt pulley. I'll install those along with the Secret Cams I have sitting wrapped up in my living room. Then when it is time for a rebuild I'm going all forged internals 086 head and HPT with 75 wet shot. Lets see if I cant high low 14's in an auto then.




In the planning stage for an all American TRD Cavalier.

i remember you marcus. did you end up with any sucess regarding the 2200? I beleive you were the one who dyno'd it with very rich numbers. If you get hp you can use it on both cars, lol. Well, i suppose if i'm thinking of a different person you can just disregard this post, but if you are, who I think you are, I'd really like to know about the 2.2. either way good luck with your build. I say go for an na build with some nitrous. nitrous is always fun

the lemur wrote:i remember you marcus. did you end up with any sucess regarding the 2200? I beleive you were the one who dyno'd it with very rich numbers. If you get hp you can use it on both cars, lol. Well, i suppose if i'm thinking of a different person you can just disregard this post, but if you are, who I think you are, I'd really like to know about the 2.2. either way good luck with your build. I say go for an na build with some nitrous. nitrous is always fun

Yeah, you're thinking of the right person. The 2200 was my ex-wife's and at this point I'm not too likely to be involved in anything else going on with her car - money turned out to be one of our biggest problems (specifically, the fact that she was horrible with it) so nothing more really had been done with her car after it was dynoed. Very rich was an understatement - I was looking at a scan of the dyno a few days back and that sucker was between 10.5:1 and 11:1 for pretty much every RPM above about 3500.

Does the 2.4 tend to run that rich stock as well? Because if that's the case I'm sure that a good tune with HPT and just minimal bolt-ons would yield some nice gains. I really think with slightly advanced timing and a leaner A/F her auto 2200 could have gone from 85 whp to at least 95 if not 100 whp. I believe I've read that a stock (or near stock) 5 speed 2.4 would dyno around 120 whp or so, maybe a bit more. With just I/H/E and a good tune with HPT I wouldn't be surprised if that could be taken to 150 whp pretty easily, that is if all of the J's tend to run that rich from the factory.

I've always been a fan of all-motor setups myself as well - it's not that I think it's cheating to go with FI but I just think it's cool to see how much power you really can get out of an engine without it. Plus there's that standard of tuning - a good tuner supposedly should be able to get at least 100 HP from every liter of displacement. Following that logic, 240 crank HP from the 2.4 shouldn't be too difficult if done correctly, and a bit higher than that would still be reasonable. I haven't seen any reason that a daily driven 200+ whp 2.4 isn't realistic, and I think in this car, for my goals, that sort of power would be plenty adequate. And then with a bulletproof build, a 75 shot, or hell even a 100+ direct port shot for the occasional 1/4 mile pass would put the car down in the low 13's I'd think...if not 12's.

2. Karo, 12.051@111.767 (N2O)

i think 12's is reasonable, lol. karo's build doesn't sound too far off from what your talking about doing, his was just a little more extreme. either way that gives you an idea. A while ago somebody posted what he used for his na set up, but I have no idea what post that was in. You should try getting a hold of him for a couple tips and what-not.

the lemur wrote:2. Karo, 12.051@111.767 (N2O)

i think 12's is reasonable, lol. karo's build doesn't sound too far off from what your talking about doing, his was just a little more extreme. either way that gives you an idea. A while ago somebody posted what he used for his na set up, but I have no idea what post that was in. You should try getting a hold of him for a couple tips and what-not.

Yeah I saw that post with what he used for his NA setup...and yeah it really didn't seem that far off (he ran a low 13 NA, didn't he?). And sh!t, damn near 11s with the spray...that'd almost be scary. I wouldn't want to make the car that fast for the strip, I'd be afraid I'd break something every time I ran it there and that would suck for a daily driver. I think he might have been using slightly higher compression than I'm thinking (10.5:1 at most), but I think mostly what made it seem so extreme is that he used top-of-the-line hardware for EVERY part of the rebuild of the motor. Definitely nothing wrong with that but I probably wouldn't be spending thousands on fasteners...

But yeah, like I said, I'm not looking to make power records - I don't have the money for that, at least not now (maybe a few years down the road, who knows). And a whole bunch of power would not only make the car not very street friendly but also not so friendly for autocross. Which is why a good NA build + N2O if I want some dragstrip fun would probably be a good combo. And pricing it out, parts wise (not including the cost of catback and header which I'd have if I went with the supercharger anyways) it appears I could come in under $2000 for the parts for the all motor build - rebuild kit, HO manifold, secret cams, oversized valves, springs, etc. I don't have the skill to rebuild an engine myself so I'd have to bite the bullet and have someone else build it, but I'd like to think I could figure out how to do a lot of the rest of the work.

I think the all motor route looks like a good deal...now all I need is the $$$. *starts new-job hunting*