115 trap speed build advice

[slaby86]

First off, this forum is incredible. So many hours of my life have been spent here reading and searching and reading more. This is my first post besides my intro.

I have an 87 T I bought back in January. It was the right price at the right time (had to sell my AMG due to divorce and this car was an affordable fun replacement). It ran decent enough but also had a long list of issues and what I believe to be a history or poor maintenance. The VIN and RPO codes also indicate the car originally came with a 307 so the GN motor and drivetrain were swapped in at some point in its life, probably from a rusted out T because it's indistinguishable without checking the numbers.

Blah blah anyway, I have the grand fortune or living a reasonable distance from Richard Clark's Garage and Xavier is currently going over the whole car to ensure it is running in top condition with no mechanical defects, then we are adding a little performance to the mix. I'm on a $10-12,000 budget. I expect at at least $5000 of that to be spent on repairs (they're already replacing the rear end) which include a tranny rebuild. That leaves about $7000 for performance, slightly more if the repairs/restoration goes smoothly. The car currently has:

Stock turbo
Stock IC
50# injectors (unsure of their flow quality as they are the old style green striped)
Adjustable FPR
THDP
Unknown fuel pump
Stock MAF
TT chip
GTA wheels

I believe everything else is stock, but I really have no idea because the car had the remnants of an alky kit and actually had a TT alky chip installed when I bought it, so some parts were obviously removed from the car before I bought it.

My goals are trap speed based rather than ET based, and I haven't had any luck searching for the kind of discussion I'm interested in. The car will be literally 99% street driven. Probably not daily, but I want it to be reliable enough for a daily driver. I doubt it will ever see the track. I have a lot of drag racing experience, I just don't really care about track performance with this car. I want it to be a mean street car. It will wear street tires almost exclusively. MAYBE DRs if it is just too much of a handful. I'd like it to be capable of 115-116mph trap speeds though. I believe that would place it in the 450-500whp range. Someone please correct me if that's off.

So in saying all that, if anyone is still reading, I'd like to hear people's opinions as to what performance mods may get me there within my budget. I'm leaning heavily on Xavier and Richard Clark for their input since they are building the car, I just like soaking up the massive amount of wisdom from the guys on this forum with their own experiences and considering all options.

My thoughts were:
Bigger turbo (I'd love to hear turbo recommendations, I'm thinking bigger than a 49 or 44 to run less boost and more fuel to reach my goal)
Converter based on turbo choice
FMIC or duttneck mod (cost dependant)
LS1 MAF w/ translator
Potentially larger injectors
Alky kit
Ported stock intake

I believe that still leaves me with a few thousand bucks to play with. So what are your thoughts on my mod list, as well as any additional mods necessary? Will those moods alone get me to my goal? Should I use the extra cash to port my stock heads? I'm open to all ideas and suggestions. And like I said I have absolute faith in RC and Xavier to get me where I want to be. I'm just curious to see different approaches to the same goal. I also need to have a small budget cushion for some smaller unstated upgrades like gauges, boost control device, etc.

 

[dank GN]

The first thing on that list should be a scanmaster . You also don’t need a Intake Manifold as the stock ones are good into the 9s aswell as the headers . So I would get a scanmaster or powerlogger first . Then I would swap the valve springs for some 980s or 981s . Then a alky kit and a turbo tweak chip so you can actully turn the Boost up safely . Then turbo and converter . Fuel pump Hotwire and 80lbs injectors . It just can go on and on but the very first thing needs to be a scan tool

 

[forcefed3.8's]

TE44 turbo, PTE stock location intercooler, fresh valve springs, replace fuel pump with a known unit, 25psi boost and race gas or alky. Stock converter will work with a garrett exhaust housing. You can get a good converter from full throttle too. Your goal can be reached with a stock intercooler.

 

[forcefed3.8's]

A bigger turbo over a 44/49 will not make more power on less boost. And a ported intake is not needed until deep in the 10s with ported heads.

 

[Gary Durden]

What about the sport suspension. I doubt they swapped that also. I would think it would drive and handle better. I have been in both with and without the suspension with the turbo motor and you could tell a difference in the way they drove and handled. Good luck with the upgrades.

 

[turbo89]

A bigger turbo over a 44/49 will not make more power on less boost. And a ported intake is not needed until deep in the 10s with ported heads.

X2 .. what he said

 

[slaby86]

Thanks for the replies! On the first comment I have a scanmaster in the car. I forgot to list that. That was my first addition when I bought the car. I am having the rear control arms boxed and I'm considering suspension upgrades but I didn't list that because I wanted to keep the topic focused on the power aspect so the thread doesn't stray too far from my primary question.

My reason for wanting to make a little more power at lower boost levels is strictly for head gasket protection. I'm hesitant to pull the heads unless there is an issue identified or I decide to have them ported because I have no idea if they have ever been removed from this motor and as of now there are no head gasket issues. Since its a street car that will be driven hard, I'd like to keep boost between 20 and 22 psi. I know with alky it can be pushed harder than that but I'd rather not push the limits. Can you be a little more detailed in how a larger turbocharger will not produce more power at less boost? It's my understanding a larger unit will move more air at comparable boost levels to a smaller unit, requiring more fuel to be added to compensate. More air and more fuel should equal more power? If your comment is true why would anyone run a larger turbo than a 49/44 if they're not running over 23 psi? Is this because the stock heads are bottlenecking it?

Remember I don't care about ET. I know the population here bases most performance gates on ET but is not how I'm measuring my performance goals. I don't care about a perfect launch on a prepped track with slicks or radials because I won't be doing that with the car. I guess the reason my goal is trap speed based is because that's an indication of horsepower. I'd like to see ~450 whp. That will give me the street performance in desiring. I'm not seeking bragging rights or to compare my car's performance.

To give a little more insight, this car replaced an E63 AMG Mercedes. That car was a rocket, with just over 500hp and slightly less tq. I ran a 12.68 in the quarter with it pretty consistently on summer performance tires, with about a 112 trap speed. It was a heavy car and it couldn't launch super hard due to street tires, a low stall converter, and no 'launch mode' like the newer models have. I would like the Buick to be quicker, both from a dig and from rolling at highway speeds. The Merc was rarely shown up on the street and I'd like the Buick to be the same or quicker. That is a tall order since the buick lacks some drivetrain advantages (7-speed, torque vectoring, etc).

So in saying all that my performance goals are strictly street oriented. The only reason I even stated the 115 trap speed is to see what other guys are running close to that and compare horsepower at that performance level, and what mods achieved that goal.

 

[slaby86]

I should clarify, because the way I worded some things may have caused confusion. A bigger turbo should make more power than a smaller turbo at the SAME boost levels. So rather than run a 44 at 23-24 psi, I'd prefer to run a larger unit at 20-22 psi and see the same output.

 

[dank GN]

I hope you don’t think you can run anything above 16psi on pump gas only . If you want to run anything above that and not be poping head gaskets you will need alky . I was runing alky and 91 octane with a te60 at 25psi no detonation . That put my mph at 117 in the 1/4 .

 

[slaby86]

Alky is definitely on the mod list for me. Thanks!

 

[SCOOBY DOO]

Retaining headgaskets depends upon ones tuning abilities. What Rob mentioned in reply 3 is spot on as to what you need.

 

[forcefed3.8's]

I should clarify, because the way I worded some things may have caused confusion. A bigger turbo should make more power than a smaller turbo at the SAME boost levels. So rather than run a 44 at 23-24 psi, I'd prefer to run a larger unit at 20-22 psi and see the same output.

A bigger turbo wont make more power with less boost

 

[slaby86]

Can you elaborate? Larger turbos flow more CFM at the same psi. How does this not equate to more performance potential? This was a really good read:
https://www.rx7club.com/3rd-gen-archives-73/why-bigger-turbos-make-more-hp-same-psi-645551/

Psi does not directly correlate to the amount of air moved by the turbo into the motor. That's why larger turbos require larger fuel injectors in some cases even without increasing boost. That being the case if you're burning MORE fuel to maintain acceptable a/f ratios after installing a larger turbo, how does it not generate more power?

 

[dank GN]

It’s all about the combo . You can only shove so much air through a 2”x1” opening . Here are acouple pictures of some heads I’ve ported for acouple customers .

 

[bison]

Thanks for the replies! On the first comment I have a scanmaster in the car. I forgot to list that. That was my first addition when I bought the car. I am having the rear control arms boxed and I'm considering suspension upgrades but I didn't list that because I wanted to keep the topic focused on the power aspect so the thread doesn't stray too far from my primary question.

My reason for wanting to make a little more power at lower boost levels is strictly for head gasket protection. I'm hesitant to pull the heads unless there is an issue identified or I decide to have them ported because I have no idea if they have ever been removed from this motor and as of now there are no head gasket issues. Since its a street car that will be driven hard, I'd like to keep boost between 20 and 22 psi. I know with alky it can be pushed harder than that but I'd rather not push the limits. Can you be a little more detailed in how a larger turbocharger will not produce more power at less boost? It's my understanding a larger unit will move more air at comparable boost levels to a smaller unit, requiring more fuel to be added to compensate. More air and more fuel should equal more power? If your comment is true why would anyone run a larger turbo than a 49/44 if they're not running over 23 psi? Is this because the stock heads are bottlenecking it?

Remember I don't care about ET. I know the population here bases most performance gates on ET but is not how I'm measuring my performance goals. I don't care about a perfect launch on a prepped track with slicks or radials because I won't be doing that with the car. I guess the reason my goal is trap speed based is because that's an indication of horsepower. I'd like to see ~450 whp. That will give me the street performance in desiring. I'm not seeking bragging rights or to compare my car's performance.

To give a little more insight, this car replaced an E63 AMG Mercedes. That car was a rocket, with just over 500hp and slightly less tq. I ran a 12.68 in the quarter with it pretty consistently on summer performance tires, with about a 112 trap speed. It was a heavy car and it couldn't launch super hard due to street tires, a low stall converter, and no 'launch mode' like the newer models have. I would like the Buick to be quicker, both from a dig and from rolling at highway speeds. The Merc was rarely shown up on the street and I'd like the Buick to be the same or quicker. That is a tall order since the buick lacks some drivetrain advantages (7-speed, torque vectoring, etc).

So in saying all that my performance goals are strictly street oriented. The only reason I even stated the 115 trap speed is to see what other guys are running close to that and compare horsepower at that performance level, and what mods achieved that goal.

115mph on 93 only will require a good set of heads and probably an Intercooler update. Turbos support mass flow. They don't make power that's why a larger turbo than the suggested will not necessarily make more power with what you're looking to do. The T04e60 compressor and t31 turbine is good to about 55lbs/min. To trap 115mph at 3700lbs you will need about 45lbs/min of air and it will easily cover that but it's not happening on hot summer days with a stock Intercooler and 93 octane without an anti-detonant. The T04e60 compressor is really happy at that mass flow range especially if you can get the pressure ratio around 2-2.5:1 PR. Still not making excessive heat and spools on a stock converter. The good heads will keep the PR in check for the mass flow needed. It won't ever have that neck snapping low end grunt of an E63 but can be updated to suit your goals and can be a lot of fun on a set of drag radials without too much down side. Also manifold pressure doesn't dictate head gasket longevity. We've ran 30+psi on stock head gaskets with an anti detonant with no problem. With 93 only and stock heads you will be left underpowered and disappointed by the performance of the 30 year old v6


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[slaby86]

Awesome Bison that all makes perfect sense. Sounds like porting my heads is on the to-do list of its within my budget. I will definitely be adding alky as well. Thanks for your input!

 

[murphster]

The only thing that doesn't make sense is why you need to keep boost at 20-22psi. You'd be wasting a lot of money to build a combo around that rather than just building something that keeps boost within a safe range of the turbo that is spec'd correctly for the combo. You can run stock heads and will need higher boost to run 115mph or have good ported heads and run lower boost but you're still making the same power. Bad tune will still take out head gaskets.

I would go for one of Bison's 6262 turbos with a Garrett housing and a mild converter if it were me and keep the stock heads for now. And I would seriously look at something like a PTE stock location intercooler or maybe a used CAS V4 or similar. Better than a dutt neck and you can grow into them. Get the rest of the car running good, make sure valve springs are ok, etc, get the alky kit and some decent street tires and its a killer street car that will meet your goals. Down the road you can do heads and cam along with plenum, tb, intake etc if desired but now you are looking at a whole different level as in 120mph+ range. And it makes sense with your budget range, maybe a little under budget for now but to do everything correctly would take you well over budget. Phase 1 and 2.

 

[bison]

The only thing that doesn't make sense is why you need to keep boost at 20-22psi. You'd be wasting a lot of money to build a combo around that rather than just building something that keeps boost within a safe range of the turbo that is spec'd correctly for the combo. You can run stock heads and will need higher boost to run 115mph or have good ported heads and run lower boost but you're still making the same power. Bad tune will still take out head gaskets.

I would go for one of Bison's 6262 turbos with a Garrett housing and a mild converter if it were me and keep the stock heads for now. And I would seriously look at something like a PTE stock location intercooler or maybe a used CAS V4 or similar. Better than a dutt neck and you can grow into them. Get the rest of the car running good, make sure valve springs are ok, etc, get the alky kit and some decent street tires and its a killer street car that will meet your goals. Down the road you can do heads and cam along with plenum, tb, intake etc if desired but now you are looking at a whole different level as in 120mph+ range. And it makes sense with your budget range, maybe a little under budget for now but to do everything correctly would take you well over budget. Phase 1 and 2.

He's running 93 only. No anti-detonant


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[bison]

Awesome Bison that all makes perfect sense. Sounds like porting my heads is on the to-do list of its within my budget. I will definitely be adding alky as well. Thanks for your input!

Alky changes everything. If you're going to be doing the heads and adding alky you can increase mass flow a bunch with airflow and manifold pressure. The 62 may be the way to go at that point. Most struggle to get enough fuel in the cylinder when the heads have been done. Timing requirements change and fuel requirements increase a lot. You're feeding a lot more airflow and it's at higher rpm. Running an external gate off the header would be wise at that point also


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[slaby86]

The only thing that doesn't make sense is why you need to keep boost at 20-22psi. You'd be wasting a lot of money to build a combo around that rather than just building something that keeps boost within a safe range of the turbo that is spec'd correctly for the combo. You can run stock heads and will need higher boost to run 115mph or have good ported heads and run lower boost but you're still making the same power. Bad tune will still take out head gaskets.

I would go for one of Bison's 6262 turbos with a Garrett housing and a mild converter if it were me and keep the stock heads for now. And I would seriously look at something like a PTE stock location intercooler or maybe a used CAS V4 or similar. Better than a dutt neck and you can grow into them. Get the rest of the car running good, make sure valve springs are ok, etc, get the alky kit and some decent street tires and its a killer street car that will meet your goals. Down the road you can do heads and cam along with plenum, tb, intake etc if desired but now you are looking at a whole different level as in 120mph+ range. And it makes sense with your budget range, maybe a little under budget for now but to do everything correctly would take you well over budget. Phase 1 and 2.

Awesome that all makes sense. Thanks! I will definitely post up the combo I end up with after Richard Clark is finished with it!