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Discussion Starter #1
Somone asked if I had posted a mod thread, and I hadn’t as I avoided mentioning doing anything to my car as long as it was on warranty. No reason not to post now.

I bought my GXP manual transmission coupe (one of 281) on August 20, 2009. That means that my warranty has now expired and I am able to talk about my upgrade process with the car without endangering any coverage, so I thought I’d post a synopsis of my development path on this car. Long and potentially boring, so avoid if tech isn’t your thing.

Background: I have been building road racing and streetable sports cars since 1973 when I took my daily driver, an MGA, off the road and outfitted it for competition use, and bought a trailer. That was about a two year learning curve where I ran a dozen races a season, and in between races I figured out why any part that had broken had failed and fixed it in a way that was intended to prevent that particular DNF mode from recurring. Along the way, I got in a lot of track time and became a smoother and competitive driver, while sorting out my then 15 year old car (which I still own).

I’ve owned between 70 and 80 cars over the intervening years and have probably modified 90% of them to improve performance, so I developed a pretty good sense of what made a difference and what was just window dressing. I also got good enough at wrenching to be able to avoid most potential problems in advance, rather than fixing things after they went wrong (my transplant of a GM 3.4 V6 and T5 gearbox into another 1956 MGA that had a Fiberfab Jamaican body on it, worked so well that it started the first time I turned the key and nothing at all failed to work except the tach which needed an amplifier unit and the speedo, which wasn’t getting a signal from the GM sensor in the trans.

I was driving the 1988 Fiero GT that I had built with a 3.2 stroker motor and a turbo (c. 300 bhp) in the early 90s and was thinking that after 20 years it might be time to move on to something else. I’d joined the Solstice site back in 2007 when the GXP provided enough power to interest me, but at that point the looks of the convertibles didn’t really attract me enough to make me think of buying. Then in the summer of 2009 I happened to drop by the local dealer for something and saw a coupe and fell instantly in lust with them.

I called around and found a dealer that actually had some for sale (they brought about 80 into Canada and maybe a dozen to BC), and the next day went over to look at them. They had a black with no air, a lovely blue (the only one to come to Canada), but an automatic, and a couple of others but only one manual trans with air, a gray car, number 378. I bought it on the spot and made an appointment to pick it up the next Saturday. I was happy to get it and though it wouldn’t have been my first choice for colour, with only 46 manuals coming into the country I took what was available.



Performance improvements:

In the intervening week after ordering the car, I gave myself an intensive course in the technical end of the Solstice, reading four years of posts on a couple of sites to see what did and didn’t work on the cars. Before I had even picked it up, I’d put in an order for the GMPP kit to bump the power. It was installed the week after I received the car, which gave me enough time to appreciate the difference.


I added on a high flow CAT from Solo and an exhaust system (which was another story – the Street Race was much too loud on a coupe – mine was the first coupe they’d sold one for – and I swapped out for a Mach which sounds nice without giving you headaches Good deal available on a Street Race with maybe 200 km. on it!). No added power from the system, but nicer sound. I also stuck in a GMPP intake, not for performance (there isn’t any to be had there either) but to avoid issues with broken tubing elbows on the stock plastic assembly and to clean up the engine bay. I added DDM intercooler tubes and a larger Werks intercooler in preparation for future performance increases (they do nothing with a stock or mildly tuned set up).

I also researched what could be done to safely increase power beyond the GMPP stage. I bought a Trifecta tune after talking to Vince Geglia (he was more readily available in those days). I asked him if he would agree to retune if I swapped turbo units later and he agreed, and said they hadn’t done any Solstices yet with larger turbos but that there should be no problems. The tune went in shortly after I bought the car and the big wheel turbo followed in the Spring of 2010, tuned with maybe five different data logs being exchanged to get it just right. It was now putting out around 26 psi and was an impressive step above the standard Trifecta tune. The exact same set up was getting high 12.9 sec. 1/4s and dynoed at 324 hp/347 Tq at the wheels with another member I corresponded with (obviously dyno readings vary, but that gives an idea of the results). Any other larger/different turbo would have been a red flag if there had been any warranty claims so I opted to stick with this one until warranty ran out.



Handling mods:

Once I got the car, I took it out and started investigating the handling. I found a couple of flaws. The shocks and springs were predictably middle of the road choices calculated not to cause complaints about harshness by people just using their cars to drive to the mall. There was an annoying unsettled period near the apex of a hard corner (most people probably wouldn’t notice unless they corner very hard) where the car seemed to give a little lurch and lose grip. The stock brakes sucked as far as initial grip and stopping distance were concerned. I researched and talked to some of the guys running slalom competition and ordered up the ZOK bars front and rear (for solo competition they often use a stock front, but for street the ZOK front is my preference) as well as a Backbone and Probeam from DDM. All that went in within a month of me getting the car. I also added a complete set of adjustable BC Racing shocks and uprated springs within a short time, which cured the handling issues. I later added a front brace as well for a smaller but worthwhile improvement. We aligned the car a bit aggressively, and for fun I also corner weighted it, although that is something I normally reserve for the race cars.


Other mods:

I was annoyed that the factory brochure showed the twin spoke Q9Y wheels but you couldn’t buy the car with them, an error on the Canadian brochure. An early mod for me was picking up some NOS Q9Y wheels on Ebay. I eventually swapped out brake pads for EBC Reds and am much happier with them. I also added a good on board Radar/Laser detector (the new Passports had just come out and the old model – SRX – was available at around half price on Ebay, new in the box. I also added, quite early, a sonic back up alert, a proximity alarm to deal with the horrid rear visibility of the coupes when backing up.

I had early on bought a plate to obscure that annoying air bag light, and I’d ditched the plastic engine cover for a painted cam cover that actually made it look like you have an engine under the hood instead of a Tupperware collection, but otherwise I had lived with and largely ignored the various interior aspects that were awkward or displeasing – badly placed window switches, tunnel covers you couldn’t lean on without cracking, gauges located at the bottom of dark tunnels that preclude you actually reading them in bright sun and such.

So I’ve driven the car in stock form, with GMPP tune, with Trifecta tune, and with Trifecta retune with big wheel turbo, four stages in all. I’m sure you can guess which way is the only way I’d want to own it! The result is a great combination of performance and economy (once I got over the initial fun factor and started driving without the accelerator always heading for the floor), and the handling is really excellent – I was driving a local winding highway at what felt like about 8/10ths (you can’t see the speedo on a Solstice in bright sun, see above) and looked down while in a patch of shade and saw that I was doing 100 mph in a broad turn without even drawing a comment from my passenger, She-who-must-be-obeyed (and she is quick to ‘comment’ if she feels one is driving too fast!).

There are a lot of mods out there that don’t do much (or anything) for performance, but I stick to things that I get some pay back from and have been very happy – I am now considering one final modification, a larger turbo, but want it to be consistent with a stock engine. Seriously looking at the EFR 6758 for that. And a new set of tires as the stock ones have hardened over the last five years, although with only 8,000 miles on them they haven’t worn much yet!


 

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Just because stuff is over my head, beyond anything I know or understand, doesn't mean that I can't enjoy reading about it.

And when it's as well organized and written as the above, I enjoy it even more.

Thanks, Bill!

Your car's a beauty. I hope you've grown to like the colour (getting in the spirit of the owner's homeland) more than you did initially, because I think it's very nice looking.
 

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Just because stuff is over my head, beyond anything I know or understand, doesn't mean that I can't enjoy reading about it.

And when it's as well organized and written as the above, I enjoy it even more.

Thanks, Bill!

Your car's a beauty. I hope you've grown to like the colour (getting in the spirit of the owner's homeland) more than you did initially, because I think it's very nice looking.
I had a similarly coloured Mustang once. No one can see the damn things. Everyone kept trying to hit me. Good luck with it.

Now if it were a nice bright red or maybe even yellow . . . .:lurk:
 

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Discussion Starter #6
I had the chance to get a red one out of Calgary - for an extra $1,000, sight unseen. My quandary was that if I ordered it and waited a couple of weeks for it to arrive and something happened (Oh, sorry, don't know why that showed in inventory, it was promised to a local customer) then I might have missed out on getting a manual shift coupe altogether. And as I haven't seen a manual coupe for sale here in the last 5 years (couple of autos only) that would have meant forever unless I went hunting elsewhere.

Ironic, as one of my other enthusiasms is wine and the coupe in question was, IIRC, Merlot!

The colour is fine - you don't see the outside when you are driving, and I have come to think of it as stealth/elegant. But then my colour sense is suspect in any case as I once painted a Triumph TR-3 in Mopar Plum Crazy (purple metallic).....

I'd have liked a green coupe, but sadly they didn't make any!

As for future posts, I tend to modify my cars soon after I get them, attain a permanent state fairly quickly, and then leave them alone. Perhaps having built so many race and street cars has honed my selection skills so that the biggest decision issue is choosing a colour to paint them (I still have trouble with that).

If I do swap out the turbo, I will certainly post on that, though. It's been a bit of a strain not being able to reply truthfully for the last 5 years when someone asks me how I know when I posted on tunes and various mods....
 

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wspohn.
I have also as you know the larger wheel and mine is tuned by Dave at DDM.
Mine is about 360 BHP/300 RWHP and 347-350 torque.
I do not have a HFC so the difference from yours to mine of an additional(390 BHP/324 RWHP) 30 BHP must be the HFC in combination with the exhaust.
I was going to do the EFR until I changed my mind an purchased a 2015 Z51 Stingray with the magneteic ride option.
I think if you are going to go with the EFR6758 you go ahead and upgrade the pistons and rods and valve springs.
With your present setup as you know you are close to 400 BHP, the EFR will put you well north of that, so the engine must be upgraded.
 

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Discussion Starter #8
I can't disagree with you, Alvaro, but with only low mileage on my engine I prefer to leave the internals stock for now and use it conserrvatively with a larger turbo. I'm not a drag racer and I have no problem (as others seem to have) with shifting at a sensible rpm, especially given the broad torque curve of these engines. If it comes to grief, I'll try and remember to say 'you were right'!

I wouldn't take the dyno figures too literally - you know as well as I do the variability between dynos. The figures I quoted are from this thread and from Scott (sbindley) first mod on his coupe (before he went V8) where he had Werks do a big wheel turbo. I'm not a drag racer, I just enjoy having a nice power reserve when driving the canyons and winding roads.

http://www.solsticeforum.com/forum/f102/werks-big-wheel-going-5-speed-coupe-58949/
 

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I had a similarly coloured Mustang once. No one can see the damn things. Everyone kept trying to hit me. Good luck with it.

Now if it were a nice bright red or maybe even yellow . . . .:lurk:
Rob I can certainly tell you.....yellow does not make people see you. I am always dodging people and i use those damn DRLs. :cuss:
 

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I had the chance to get a red one out of Calgary - for an extra $1,000, sight unseen. My quandary was that if I ordered it and waited a couple of weeks for it to arrive and something happened (Oh, sorry, don't know why that showed in inventory, it was promised to a local customer) then I might have missed out on getting a manual shift coupe altogether. And as I haven't seen a manual coupe for sale here in the last 5 years (couple of autos only) that would have meant forever unless I went hunting elsewhere.

Ironic, as one of my other enthusiasms is wine and the coupe in question was, IIRC, Merlot!

The colour is fine - you don't see the outside when you are driving, and I have come to think of it as stealth/elegant. But then my colour sense is suspect in any case as I once painted a Triumph TR-3 in Mopar Plum Crazy (purple metallic).....

I'd have liked a green coupe, but sadly they didn't make any!

As for future posts, I tend to modify my cars soon after I get them, attain a permanent state fairly quickly, and then leave them alone. Perhaps having built so many race and street cars has honed my selection skills so that the biggest decision issue is choosing a colour to paint them (I still have trouble with that).

If I do swap out the turbo, I will certainly post on that, though. It's been a bit of a strain not being able to reply truthfully for the last 5 years when someone asks me how I know when I posted on tunes and various mods....
Bill, that may have been me asking if you had done this in another thread a few days back. In any case, here it is now, I had always thought you were pretty much stock motor wise until that other post, now I know otherwise thanks to some history here. I for one appreciate the time you took here to document all this, it's not like you put up a couple paragraphs and called it a day.:thumbs:

How strict are your emissions? I'd love to do the Solo cat, likely call it a day, but our first emissions sessions here in Colorado, it was so satisfying to pass with flying colors, it would just be painful to fight with this down the road.

26psi these days, I would love. As you likely know, the Mercedes 2.0 AMG uses apx. 26.1 psi to produce their motor or flywheel 355 HP. I've only glimpsed a 23psi 1 time with our car with GMPP. Generally I don't see much over 20, occasional 21 or 22 (rare on 22). Automatic. Even then the car is impressive. Anyway, thanks for the sharing.

Edit: PS, make your rims work with any slightly wider rear rubber, like your rims.
 

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Discussion Starter #11
I don't think you would have any problem, but why not contact Jeff and ask if they have data on testing done on cars with their CAT?

I haven't had to test mine yet and now I won't, ever, as they have discontinued the emisssions testing in BC as of next year, so I just missed it.
 

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That turbo mod you are running has me thinking now... :cheers:
 

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Discussion Starter #13
That turbo mod you are running has me thinking now... :cheers:
The big wheel turbo was a great solution to wanting to increase flow without a giant tip off to dealer mechanics that they should void your warranty. It appears dead stock.

Today, with warranty no longer an issue for most, going straight to a larger EFR turbo is perhaps preferable, and that's what I'm thinking about; I just don't want to have to tear down an essentially new engine to rebuild to do it safely. There seem to be a number of people that are getting away with a larger turbo and keep it together by sensible use and conservative tuning. How much of a bump that would give over the big wheel I have now is the question. I suspect enough to be worthwhile!
 

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I just don't want to have to tear down an essentially new engine to rebuild to do it safely...
This is the money quote for me. I am interested in engine longevity since this is my daily driver and I haven't even broke 30K yet. After reading many posts on the forum, I think it adds just enough kick to make it worth while and save on engine stresses. The turbo world is massively new to me and its already hard to keep my foot out of it when driving. ;)
 

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Discussion Starter #16
Subscribed.

Red & Yellow are for Attention Wh*res. :devil:
Yeah, yellow has never turned my crank, although I did own a yellow (and very rare) American car once.




OTOH, I currently own 4 red cars, so I guess I am partial to them (and liked the Merlot colour for the Solstice).

Apparently there is no truth to the theory that red cars get more tickets and non-red cars are in more accidents.
 

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Discussion Starter #18
Which big wheel turbo do you have. That piqued my interest...
I used the Werks unit - K04 with a WR-1 46.5 mm compressor wheel and the housing machined to suit. Works very well with the Trifecta tune they did for it.
 

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Discussion Starter #20
Bill,
I had no idea you had done all those mods. I was aware however, of some of them. Suspension for example. ;)

Have fun with it, and remember - you can always paint it green if you choose to.:devil:
Yeah, that was kind of the idea - what GM doesn't know won't hurt me!

I hate repainting cars and changing colours - twice the work and expense. But I do like green!

How's my old suspension doing? Smoothin' your cruisin', I trust!;)
 
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