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So after my dyno with the mods i listed on the previous page i only got 285 than after some more tuning it actually went down to 279hp due to bad gas. What will i need to do to reach the 300hp mark, the mechanic suggested a intake but didn't think that it would add any hp just sound am i wrong?
 

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So after my dyno with the mods i listed on the previous page i only got 285 than after some more tuning it actually went down to 279hp due to bad gas. What will i need to do to reach the 300hp mark, the mechanic suggested a intake but didn't think that it would add any hp just sound am i wrong?
No, you are exactly right.
 

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Here is my dyno sheet on my old GXP that's running meth. On straight motor with all the bolt ic pipes, intake, solo exhaust with hi flo cat and intercooler it put down 290. With the the meth I gained an extra 30 horsepower once tuned.

 

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Discussion Starter #85
What was your goal again? That graph, your putting down 320 HP and 358 TQ, what more do you want from stockish setup (no big turbo and what not right?). And that's dyno rear wheel numbers, so that's a lot more than my 290/325 engine numbers.
 

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What was your goal again? That graph, your putting down 320 HP and 358 TQ, what more do you want from stockish setup (no big turbo and what not right?). And that's dyno rear wheel numbers, so that's a lot more than my 290/325 engine numbers.
I didn't really have a goal lol and yes that was to the wheels. But if you have all the bolt ons you can try meth or running e85 and that will def break 300hp but you will need a good tuner. Unless you want to go bigger turbo. Yes that was with the stock turbo.
 

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Discussion Starter #87
I didn't really have a goal lol and yes that was to the wheels. But if you have all the bolt ons you can try meth or running e47 and that will def break 300hp but you will need a good tuner. Unless you want to go bigger turbo. Yes that was with the stock turbo.
Well, I think you need to get to the track so you can change your track times listed.

I had plans for our coupe, and then decided no. Stock basically with GMPP. I have the Hahn IC, but that is being kept as a spare. I thought about Cat convertor change and then changed my mind with a few threads relating to problems. So she stays as is. So far the car has given us zero problems, so we like that. This spring it's time for coolant flush, and I'm actually going to let a Cadillac dealer do that (has credentials as a former Pontiac dealer).
 

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That was my old car that I sold to a friend of mine and it's still running good. My car was one of the prototype cars for the hi flo cat and never had a problem with it. On my 08 Gxp I have now I'm going the same direction and have all the parts just waiting on my exhaust to arrive this week. My old yellow car should run in 12's as I didn't run it with the meth.
 

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So after my dyno with the mods i listed on the previous page i only got 285 than after some more tuning it actually went down to 279hp due to bad gas. What will i need to do to reach the 300hp mark, the mechanic suggested a intake but didn't think that it would add any hp just sound am i wrong?
High flow cat if you don't have it.
 

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If you install the intercooler and and but the cat and exhaust then you should be over 300
 

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What was your goal again? That graph, your putting down 320 HP and 358 TQ, what more do you want from stockish setup (no big turbo and what not right?). And that's dyno rear wheel numbers, so that's a lot more than my 290/325 engine numbers.
Yeah, what's the problem - he already got what he said he wanted and more.

Big difference between BHP and WHP. for 300 whp you are looking at fuel changes or a bigger turbo, no?
 

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Yeah, what's the problem - he already got what he said he wanted and more.

Big difference between BHP and WHP. for 300 whp you are looking at fuel changes or a bigger turbo, no?
for sure.

I thought a larger intercooler w/only suggested if a larger larger turbo was being installed? Or if someone thought the OEM intercooler was reliable enough when installing moderate upgrades?

Also, are there any HP benefits adding an aftermarket header to the standard tune, HFC, and performance exhaust formula?
Pontiace Solstice Saturn Sky 07 08 09 10 DDM Header Exhaust 2 4L 4 1 Ceramic | eBay
CT, hasn't this been covered in that the standard tune (are you meaning totally stock 260 HP?), will not allow added benefit from the items you mention? The GMPP tune or more aggressive tunes will allow these add on's to help. The IC benefit has been debated, it certainly helps with any larger turbo, or very aggressive tune/fuel, but will also help with GMPP tune if you are really getting on it repeatedly (heat soak).
 

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for sure.



CT, hasn't this been covered in that the standard tune (are you meaning totally stock 260 HP?), will not allow added benefit from the items you mention? The GMPP tune or more aggressive tunes will allow these add on's to help. The IC benefit has been debated, it certainly helps with any larger turbo, or very aggressive tune/fuel, but will also help with GMPP tune if you are really getting on it repeatedly (heat soak).
No, I just mean the standard formula suggested for increasing the 2.0 from OEM 260HP to over 290ish HP is:
1. Adding a GMPP tune or an aftermarket tune (Westers, HPTuners, Trifecta).
2. High Performance Exhaust (Solo or Magnaflow).
3. High Flow Catalytic Converter.

But rarely do I hear anyone suggest adding a free flow header to the above formula. I know several forum members have installed aftermarket headers, but don't remember reading how much of a HP benefit a header provide? Also because you seem very focused on achieving a specific HP target of 300, and if a header does help increase HP it may be something to consider.

Reason I'm not mentioning Cold Air Intake is because it appears most post say is that the only thing a CAI adds is noise, not HP. Plus the cost of a CAI voids out any supposed HP benefit. Full disclosure, I recently purchased a used GM CAI from a fellow member. But I purchased it for looks, and it may be one of those GM products not available in the future.

Bracing falls into stiffer platform, and performance tires increases traction. But a stiffer platform and better traction don't increase HP, what they do is allow the platform to be pushed further than when it was OEM. Which theoretically means a stiffer suspension and good tires should help someone take advantage of the increased HP for faster 1/4 mile or racetrack times.
 

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You will find several dynos showing that the larger bore exhausts also get you zip with a stock turbo.

The CAI is useful to clean up the engine bay and eliminate that ludircous plastic fitting everyone always seems to break when servicing the air filter, but as you said, no power bonus. I agree that it will not continue to be available indefinitely.

A header is more important on an NA car, if only because it doesn't have a sizeable impediment to flow right in the middle of the system (the turbo), but there may be some small gains to having a better designed exhaust on the LNF as well and there are some threads on that. I don't recall if they had done dynos before and after installing the header. I also doubt that it is cost effective given that the header costs maybe 50% of what a bigger turbo does, which gives far more return.
 

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Back in the day . . .

When GM power train engineers who had direct knowledge or second hand info were posting, they clearly stated that the factory cat back was not inhibiting power and that adding a "free flow" cat back was basically useless. They did agree about the high flow cat being useful.

In my opinion there are two reasons for swapping for an after market IC. First is because the stock units are occasionally failing (cracking) with tunes. Second is if you actually do heat soak your factory IC often enough to justify the added cost.


Or you can of course go with an after market IC for bragging rights alone.
 

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But rarely do I hear anyone suggest adding a free flow header to the above formula. I know several forum members have installed aftermarket headers, but don't remember reading how much of a HP benefit a header provide? Also because you seem very focused on achieving a specific HP target of 300, and if a header does help increase HP it may be something to consider.
Well than either my tune was weak sauce or i should try a different tunning method, but with the mods you just listed and i have discussed i was not able to reach the 300 mark. :yawn:
 

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Well than either my tune was weak sauce or i should try a different tunning method, but with the mods you just listed and i have discussed i was not able to reach the 300 mark. :yawn:
You are talking about this as if all dynos read exactly the same, and that is just not true. In fact there is so much variation between dynos that the ONLY way to properly assess the effect of any mods you do is to do before and after runs on the same dyno.

You are hung up on attaining a particular figure, presumably for bragging rights. I suggest that you quit saying that the mods or the tune are at fault and go get a run on a high reading dyno (that used to be a Dynojet - not sure if there is a current high reading make) and you'll probably get your magic figure.

Also, you didn't give an initial pre-mod dyno reading. You may have extracted every possible BHP from your mods already.

You are looking for 300 whp (as opposed to bhp) which would equate to something like 350 bhp. I think that expectation borders on the unreasonable for a stock turbo unit with pump fuel in any case.
 

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Well than either my tune was weak sauce or i should try a different tunning method, but with the mods you just listed and i have discussed i was not able to reach the 300 mark. :yawn:
My comments are based on the forum formula that is generally suggested when someone asks how to increase the HP of their 2.0.

If I understand what Wspohn is saying, if you want significantly more HP than the next step would be to consider adding a larger aftermarket turbo. Along w/a larger intercooler for the reasons RTE stated.

You have realistic expectations so you should get the HP you want eventually, or even by contacting one of the forum vendors for suggestions or tuning help.
 
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