Roberts 89GT Engine build.

Post by **heavywoody** » Mon May 14, 2012 9:58 am

With just internal work (ported heads, SI valves, stiffer springs, 3 angle valve job, ported/polished upper and lower intake), a couple bolt ons (which Robert has more on me in that department I feel - he has headers and a cam)...

I put down 184hp and 204tq. This is with heavier wheels and brakes too though.

99GaGT3X00 · Post by **99GaGT3X00** » Mon May 14, 2012 10:04 am

mine pulls up to 6600-6700 pretty good and still feels like it has more to give but i kinda let off around there. not sure how high the 4t45 can spin but the cam's powerband is 7k then it starts dropping off so if the engine could handle it i could theoretically spin higher than 7k.

Post by **3X00-Modified** » Mon May 14, 2012 10:09 am

heavywoody wrote:With just internal work (ported heads, SI valves, stiffer springs, 3 angle valve job, ported/polished upper and lower intake), a couple bolt ons (which Robert has more on me in that department I feel - he has headers and a cam)...

I put down 184hp and 204tq. This is with heavier wheels and brakes too though.

He also has 1 5/8" header primaries which I'm wonder if that can equate to some of the torque loss or lack of if you want to start comparing, Also as far as what he has done, the only thing over your's Geoff is the Cam, He has Bens ported heads and lower and upper, He is also at 9:1 compression vs 9.5 or higher on a 3400/3500.

And one major thing is you can never compare two different dyno's numbers from completely different locations... they aren't all created equal.

We can sit here and guess all day, but I added Spark and added fuel till power dropped and then removed it and the power came back, so if you ask me this is the limitation of this part combination, I don't know what else can be done to squeeze anymore out of it at least with the tune.

Last and first pulls attached in PDF form.

Post by **3X00-Modified** » Mon May 14, 2012 10:25 am

This is a compare of 6 and 7, I removed the air temp spark restrictions on the file to allow it to hit max spark and then added another degree over run 5 and run 6 was the result of that and peak power through the exhaust. I added one more degree with run 7 and caught 0.9 of KR at 5k plus you can see the power drop, so I removed that one degree when we did his last pull.

6-7compare.pdf: (77.25 KiB) Downloaded 333 times

I'm open to input but just remember, Robert doesn't have a way to flash his ECU and well a dyno costs money so just guessing and trying something now may not help much.

The only thing I know of for sure right now is his injectors are maxed out, but I don't think that will gain him any more power since it never went lean, it will just ensure longevity of them if he gets the 28lb ones. But I could be wrong.

LX9Power · Post by **LX9Power** » Mon May 14, 2012 10:47 am

3X00-Modified wrote:
LX9Power wrote:at what RPM? And what cam you have? torque seems a little on the low side...
What are you basing your number off of?

Dave's 3500 was putting down 275whp and 257wtq and that was with is VERY radical cam, so with a 206 duration cam and the lift Robert has I think his tq number is just fine.

The thing that suprised me is even running up to 6400 approximately we never found where the power starts to drop... I'll post a few pulls to show that too.

I was basing it of the one I saw ( granted Z24 5 speed) that got around the same Torque as him without a cam. that why I asked at what RPM ( to see if is car was not a high rpm screamer or something)

we can't compare Superdave here because his build...is well.... too extreme.

Post by **3X00-Modified** » Mon May 14, 2012 11:02 am

I'm starting to see that the cam he has is putting out around the same TQ numbers as a stock cam. Honestly not sure why, as stated above it could be the header primary size, or the injectors, but I doubt injectors for the TQ number since they were well under 80% DC at 4000-4500 RPM

Peak tq is around 4200 and then yeah peak power is at 6200-6300 which wasn't dropping at all... so I do wonder if the injectors are holding it back, but with getting an easy 12.3 a/f ratio at that RPM I have trouble believing that.

LX9Power wrote: we can't compare Superdave here because his build...is well.... too extreme.

His original build in the Z24 wasn't that radical to start, at least when he posted those numbers it wasn't.

LX9Power · Post by **LX9Power** » Mon May 14, 2012 11:08 am

what are the injectors he has?

Post by **3X00-Modified** » Mon May 14, 2012 11:33 am

stock GA 22lb/hr ones, as noted I already know they are maxing out but it never went lean so I don't know how much he would gain if anything from swapping them.. quite possibly just longevity.

He could go to the 28lb trailblazer ones for ease of install since they match his current harness connectors and then bump the fuel pressure like I have if necessary. I'm running 63PSI on the 28lb ones essentially making them 30lb/hr injectors

LX9Power · Post by **LX9Power** » Mon May 14, 2012 12:49 pm

3X00-Modified wrote:stock GA 22lb/hr ones, as noted I already know they are maxing out but it never went lean so I don't know how much he would gain if anything from swapping them.. quite possibly just longevity.

He could go to the 28lb trailblazer ones for ease of install since they match his current harness connectors and then bump the fuel pressure like I have if necessary. I'm running 63PSI on the 28lb ones essentially making them 30lb/hr injectors

63PSi must give you a way better spray...what FPR did you use to bump your fuel pressure? and maybe the 3500 and hybrids like higher fuel pressure? I really starting to think some power could be had there...Im maxing my 19lbs as well and 22lbs isn't that far from me and he got way more upgrades. how many MV did the fuel injector pulse got from 6000 to 6700?

Post by **3X00-Modified** » Mon May 14, 2012 1:03 pm

I have an old Caspers adjustable FPR, the only one out there now that will fit is from TCE, British car conversions website has one.

http://www.britishcarconversions.com/co ... gory_id=28

spacecadetz26 · Post by **spacecadetz26** » Mon May 14, 2012 3:12 pm

you can also use a LT1 adj fuel regulator, i think summit sells original style adjustable replacement.

Post by **3X00-Modified** » Mon May 14, 2012 3:47 pm

Interesting...

http://www.summitracing.com/parts/ACC-74566/

Mine will go over 60 PSI though.

Robert 89gt · Post by **Robert 89gt** » Mon May 14, 2012 6:58 pm

From my understanding of the injectors.Mine stop making power at 203WHP from what ben from wot-tech has been told.I also think jon did the best he could with the tune.The only person i know with the same car and camshaft is alxsmt.He made 218.9WHP but has 10.5:1 CR.But i have ported intakes and heads.Like i said i would like to see more power if thats possible.But if the parts are doing the most that they can well nothing i could really do about it.If you need me to flash the ecm i could try and use jeffs Hp tuners.
I don't see why he wouldn't let me.

LX9Power · Post by **LX9Power** » Mon May 14, 2012 7:45 pm

He did get 222wtq with the same cam.Not bashing what 3400-mod did because he the one I look up to for tuning, but I think your setup can do a little more.

Robert 89gt · Post by **Robert 89gt** » Mon May 14, 2012 7:54 pm

Once i get new injectors we'll see what she'll do then.Thanks again for the input=)

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